MAMMALS OF WASHINGTON

BY

WALTER W. DALQUEST

University of Kansas Publications

Museum of Natural History

Vol. 2, pp. 1-444, 140 figures in text
April 9, 1948

UNIVERSITY OF KANSAS
LAWRENCE

1948

MAMMALS OF WASHINGTON

Mount Rainier from Indian Henry's Hunting Ground, July, 1934. (Fish and Wildlife Service photo by Victor B. [Scheffer]. No. 864.)

MAMMALS OF WASHINGTON

BY

WALTER W. DALQUEST

(Contribution from the Museum of Natural History, University of Kansas)

University of Kansas Publications

Museum of Natural History

Volume 2, pp. 1-444, 140 figures in text
April 9, 1948

UNIVERSITY OF KANSAS

Lawrence

1948

(7)

University of Kansas Publications, Museum of Natural History

Editors: E. Raymond [Hall] and Donald F. Hoffmeister

Volume 2, pp. 1-444. 140 figures in text

April 9, 1948

University of Kansas
Lawrence, Kansas

Printed by
Ferd Voiland Jr., State Printer
Topeka, Kansas
1948

21-1993

CONTENTS

ILLUSTRATIONS

INTRODUCTION

Mammals of Washington are of especial interest to the naturalist because many of them are recent immigrants; much of Washington was buried under thick glacial ice until relatively recently and many of the mammals, therefore, have inhabited the area only since the ice disappeared. The evolution or development of certain subspecies, in Washington, has certainly occurred within the last few thousand years. To be able thus to date such evolutionary changes as have occurred is of course a matter both of importance and interest to zoölogists. The evolutionary changes in several species are relatively great. In color, for example, the bobcat in the humid coastal area of western Washington is notable for its dark coloration, whereas in the more arid area of southeastern Washington it is remarkably pale and of a different subspecies. Within the limits of the state of Washington, elevations ranging from sea level to more than 14,000 feet occur. Since different elevations have their characteristic mammals, more kinds are found in Washington than in other areas of corresponding size that lack such topographic diversity. Expressed in terms of the life-zone concept, Washington includes faunas ranging from the Upper Sonoran Life-zone to those of the Arctic-Alpine Life-zone.

The basis for a study of the mammals of Washington was laid in 1929 by W. P. [Taylor] and W. T. [Shaw] in the "Provisional List of the Land Mammals of the state of Washington." [Bailey]'s "Mammals and Life Zones of Oregon" and "The Recent Mammals of Idaho" by W. B. [Davis] deal with the habits and distribution of mammals in the areas bordering Washington on the south and east, and were very useful in the organization of the present report.

The study was first planned from the taxonomic and ecologic point of view. Such a study, of necessity, involves the classification and distribution of the forms concerned. Classification has required more work than any other part of the study and has been, in a sense, the nucleus of the study. Nevertheless, as the report began to take form it was recognized that the part dealing with classification and other purely technical aspects of the paper probably would be uninteresting to the average reader. Therefore it was felt that a greater impetus to the study of the mammals of Washington would be given by reducing the taxonomic accounts to the minimum and dealing principally with the problems of distribution.

As originally planned, the present report was to be of joint authorship by Dr. Victor B. [Scheffer] of the United States Fish and Wildlife Service, Seattle, and the writer. The press of other work prevented Dr. [Scheffer] from devoting as much time as he had planned to the project. He has, however, contributed his field notes, specimens, and photographs, and in many other ways assisted in the project.

Field work on mammals of Washington was carried out by the writer from 1936 to 1940 but a decision to prepare a complete report was not reached until 1938. Intensive field work was done between 1938 and 1940. In August, 1941, the author took up residence at Berkeley, California. Drafting of the manuscript was begun at that time as a student under Professor E. Raymond [Hall]. War conditions and the press of other work delayed completion. Subsequently, the manuscript was put in final form at the University of Kansas.

Many persons in addition to Dr. [Scheffer] have given assistance in the course of this work. Dr. E. Raymond [Hall], in particular, encouraged the project and gave assistance in various ways including critical attention to the manuscript. I am indebted also to Dr. Trevor Kincaid and Mrs. Martha [Flahaut] of the University of Washington, Dr. Seth B. Benson and Dr. Alden H. [Miller] of the University of California, Dr. H. H. T. [Jackson] of the U. S. Fish and Wildlife Service, Dr. George E. Hudson of the Charles R. Conner Museum, Mr. Burton Lauckhart of the State of Washington Department of Game, and Mr. Ernest [Booth] of Walla Walla College. Mrs. Peggy B. [Dalquest] typed and edited the several preliminary drafts of the manuscript and aided in the laboratory and field work. Thanks are due also to many others, including game protectors, hunters and trappers, who have given assistance. The names of some of them are mentioned in the following pages.

Approximately ten thousand specimens of mammals were used. In decreasing order, according to the number of specimens studied from Washington, the following collections are to be mentioned: materials obtained principally from southern Washington in the years 1939 to 1942 as a result of the interest of Miss Annie M. Alexander and Dr. E. Raymond [Hall]; these materials are in the University of California Museum of Vertebrate Zoölogy. The writer's own collection which at one time numbered 2,500 specimens was the second source. The residue, the part not destroyed by fire at the writer's home in the spring of 1942, in Seattle, now is in the Museum of Vertebrate Zoölogy at the University of California and the Museum of Natural History at the University of Kansas. The other collections are those of the Biological Surveys of the United States Fish and Wildlife Service, the Washington State Museum at Seattle, the Charles R. Conner Museum at Washington State College, and the Museum of Natural History at the University of Kansas. In the latter collection are some materials obtained nearly half a century ago by the late L. L. Dyche, some recently taken specimens added by reason of the provision for work of this kind by the University of Kansas Endowment Association and, as noted above, a part of the author's original collection. Selected specimens from several other collections have been used and these are indicated in the text when particular reference is made to the specimens. Most of the specimens studied were conventional study skins with skulls. In some instances skeletons, skins alone, skulls alone, or entire animals preserved in alcohol have been used.

PHYSIOGRAPHIC PROVINCES OF THE STATE

The state of Washington was divided into seven physiographic provinces by [Culver] (1936). [Culver] points out that the physiography, though complicated in detail, is basically simple.

The state, including Puget Sound and other inland waters, is nearly rectangular in shape and is 69,127 square miles in area. Its western boundary is the Pacific Ocean. Politically, it is bounded on the north by the United States-Canadian Boundary (49° north lat.), on the east by the state of Idaho, and on the south by the state of Oregon.

The Cascade Mountain Range, or Cascade Mountains Province, runs from the northern to the southern boundary and divides the state into two sections, of which the eastern is slightly the larger. The mountain range trends approximately 10° east of north and continues uninterruptedly into British Columbia, but on the south the Columbia River separates the Washington Cascades from the Cascades of Oregon. Near the northern border of the state the range is wide, extending from the Mount Baker Range on the west to Mount Chopaka, 100 miles to the east. In the central part of the state it is more compact, being some 60 miles wide in the vicinity of Mount Rainier. Farther south it expands to approximately 100 miles.

The Cascades of Washington possess five great volcanic cones. These are Mount Baker (10,750 feet elevation) on the north, Glacier Peak (10,436 feet) in the north-central part, Mount Rainier (14,408 feet) in the central area, and Mount Adams (12,326 feet) and Mount St. Helens (9,697 feet) on the south. Excluding these volcanic peaks, the crests of the Cascades have a relatively uniform level descending from an average of 8,000 feet at the north to 5,000 feet at the south. Ranges jutting southeastwardly from the north-central Cascades parallel elongate intermontane valleys. These include the Entiat and Wenatchee mountains. The latter range reaches the Columbia River and forms an important barrier to mammalian movements.

There is an extensive area of anticlinal ridges extending from the southern Cascades to the Columbia River. This area includes the Horse Heaven and other hills. Most of it is drained by the Yakima River and is termed, in this report, the Yakima Valley Area.

Fig. 1. Cascade Mountains at Canadian boundary, looking west along boundary trail. Monument 100 in foreground, headwaters of Ashnola River in broad valley at right. (Forest Service photo, No. 4328.)

The Puget Sound Trough, or Puget Sound Province, is immediately west of and parallel to the Cascade Mountains. It is part of a structural downwarp that extends southward into Oregon. Most of the area is below 1,000 feet elevation, and much of the northern part is below sea level and therefore flooded by the marine waters of Puget Sound. The most prominent feature of this area is Puget Sound. This is a glacially-carved and drowned river valley, studded with islands, peninsulas, fjords and bays that all possess a general north-south orientation resulting from the direction of ice movement. Puget Sound is connected with the Pacific Ocean by the Strait of Juan De Fuca, a wide channel separating the state of Washington and Vancouver Island.

The San Juan Islands represent the glaciated remnants of mountains that, in preglacial time, may have connected the mountains on Vancouver Island with the Cascades of Washington. The San Juan Islands lie at the junction of Puget Sound, the Strait of Georgia, and the Strait of Juan De Fuca. As a result of a boundary dispute and subsequent arbitration, the islands were apportioned, on the basis of the deepest channel separating them, between Canada and the United States. The American portion includes more than 400 islands. These vary in size from mere rocks above high tide to Orcas Island, 60 square miles in area.

The Olympic Peninsula, or Olympic Province, lies between Puget Sound and the Pacific Ocean. The Strait of Juan De Fuca separates this peninsula from Vancouver Island on the north. In the south the valley of the Chehalis River is a convenient boundary for the province. The central portion of the peninsula is occupied by the Olympic Mountain Range. This range is nearly oblong in shape, measuring some 70 miles east to west by 45 miles north to south. The mountains are extremely rough and jagged. They rise from sea level to above 6,000 feet. The highest peak, Mount Olympus, is 8,150 feet in elevation.

South of the Olympic Province and west of the Puget Sound Trough is an area of low, rough hills. [Culver] called it the Willapa Hills Province.

The northern third of the land east of the Cascade Mountains, or northeastern Washington, is termed the Okanogan Highland Province by [Culver]. Its southern boundary is set at the east-west flow of the Spokane and Columbia rivers. The outstanding physiographic feature of this area is its division into north-south trending areas of lowland with intervening highlands and mountain ranges. The rivers are, from east to west, the Clark Fork, Colville, Columbia, Kettle, San Poil and Okanogan. Not all intervening highlands are separately designated as mountains. Among these named are the Pend Oreille, Huckleberry, Kettle River, and Okanogan ranges.

The part of eastern Washington south of the Okanogan Highland Province, save the extreme southeastern corner of the state, constitutes the Columbia Lava Province. This is an extensive, relatively level plateau that lies mainly below 2,000 feet elevation. The plateau consists of gently folded lava flows that reach a depth of 4,000 feet in some places ([Russell], 1893) and slope inward from the east, north, and, in part, the west ([Flint], 1938). These horizontal layers of basalt are extremely resistant to erosion by other than large rivers. Two great gashes cross the Plateau diagonally from the northeast to the southwest; these are Moses Coulee and the Grand Coulee. These old coulees are the former valleys of the Columbia River, and were formed at the time when the course of the river was successively blocked by the advance of Pleistocene ice. The Snake River crosses the southern edge of the Columbia Lava Province and separates the plateau proper from an area of similar land to the southward.

Fig. 2. Columbia River one mile west of Kellers Ferry, Washington, elevation 1,060 feet, April 16, 1940. (Fish and Wildlife Service photo by Victor B. [Scheffer], No. 933.)

The Blue Mountains Province is an area of relatively small extent in the extreme southeastern corner of the state of Washington. There, the province concerned constitutes, as it were, a northward extension of the Blue Mountains of Oregon. The mountains rise to only 5,000 feet elevation in the Washington part of the Blue Mountains Province.

DISTRIBUTIONAL AREAS

The physiographic provinces are areas of land form. The form of the land has a considerable effect on the temperature, humidity, drainage, weathering, soil, and other non-organic features that combine to produce the various life-zones and influence the distribution of mammals. One might therefore expect a close correlation of mammalian distributional areas with physiographic provinces. Although there is a correlation, it is not exact because the distribution of mammals is influenced also by certain other factors. Among these are historical factors and isolation by geographic barriers.

Fig. 3. Mammalian distributional areas of Washington. A. Western Washington. B. Cascade Mountains. C. Northeastern Washington. D. Blue Mountains. E. Southeastern Washington. F. Yakima Valley. G. Columbian Plateau.

The Cascade Mountains Province of [Culver] includes the Yakima Valley Area. This province contains two completely different mammalian distributional areas. The higher mountains possess a boreal, alpine fauna; the Cascade Range itself is called the Cascade Area in this report. The Yakima Valley Area possesses a desert fauna derived from the desert of eastern Oregon.

The land west of the Cascades is separated into three physiographic provinces, the Puget Sound, Willapa Hills, and Olympic Mountains Province. The differences between the mammalian faunas of the Puget Sound and Willapa Hills provinces are slight. The Olympic Mountains possess a few species not found in the lower areas. The similarities of the faunas of the three provinces far outnumber their differences, and it seems best to consider them subdivisions of one distributional area.

Fig. 4. Cascade Mountains in Chelan National Forest, looking southwest at Straight Ridge; Cataract Creek (Methow watershed) at left. (Forest Service photo. No. 4260.)

The Okanogan Highland Province extends, from a physiographic point of view, west of the Okanogan River Valley. This valley, however, is a fairly efficient barrier to mammals. Thus the part of the state east of the Okanogan Valley and north of the east-west flow of the Spokane and Columbia rivers may be called the Northeastern Washington Distributional Area.

The Columbia Lava Province includes the land both north and south of the Snake River. Since the Snake River serves as a barrier to some species, it seems better to term the area north of the Snake River the Columbian Plateau Area and that to the south the Southeastern Washington Distributional Area.

The Blue Mountains Province and the Blue Mountains Distributional Area are the same.

Fig. 5. Yakima Park (or Sunrise Park), elevation 6,000 feet, Mount Rainier, August 29, 1932. (Photo by 116th Photo Section, Washington National Guard, No. 014-36A-116.)

Fig. 6. Columbia River at Hunters Ferry, Stevens County, Washington, April 15, 1940. (Fish and Wildlife Service photo by Victor B. [Scheffer]. No. 932.)

Fig. 7. Blue Mountains, Umatilla National Forest, Washington, looking north-northeast across Al Williams Ridge to Tucannon River; 1933. (Forest Service photo, No. 4437.)

CLIMATE AND VEGETATION

The life-zone theory of plant and animal distribution was proposed by [Merriam] (1892). [Merriam]'s life-zones have been severely criticized by many authors, especially because an error was made in computing some of the data on temperature. However, zonation of vegetation and animals is obvious in Washington, and the life-zone concept has been employed in Washington by numerous botanists and zoölogists. Among them are: [Piper] (1906), [Taylor] and [Shaw] (1927), Jones (1936, 1938) and [St. John] (1937).

The higher parts of the Cascade Mountains are in the Arctic-alpine Life-zone. This is the area of wind-swept ridges, living glaciers, and permanent snow fields.

Trees are absent but a few shrubs are present; these include: Juniperus sibirica, Salix cascadensis, Salix nivalis, Gaultheria humifusa, Empetrum nigrum, and the heathers, Phyllodoce glanduliflora, Cassiope mertensiana and Cassiope stelleriana. Jones (1938) lists a total of 98 species of plants from the Arctic-alpine Life-zone of Mount Rainier. Many of these plants are most abundant in the next life-zone lower, and are of but incidental occurrence in the Arctic-alpine Life-zone. No mammalian species is resident but individuals of several species regularly visit and occasionally breed there.

Below the Arctic-alpine the Hudsonian Life-zone stretches the entire length of the Cascades. Temperatures are low, especially in winter; then the thermometer does not rise above zero for weeks at a time. The average annual temperature at Paradise, 5500 feet, Mt. Rainier, is 38.6° (all temperatures given here are in degrees Fahrenheit). Snowfall is heavy. The average yearly snowfall, for four years, at Mt. Baker Lodge, at 4200 feet elevation, Whatcom County, was 478 inches; at Goat Lake, 2900 feet, Snohomish County, 261 inches; Tye, Stevens Pass, 3010 feet, King County, 398 inches; Paradise, 5500 feet, Mt. Rainier, 587 inches. The deepest snow recorded at Paradise was 27 feet, 2 inches on April 2, 1917. Following the spring thaws the mountain passes are opened to travel, usually in April or May, although nightly temperatures in April and May are still below zero. Spring precipitation is heavy, the monthly average for a twelve-year period at Paradise being 6.78 inches in April and 5.5 inches in May. Summer temperatures are high in the daytime, when the sun beats down through the rarefied atmosphere, but cool at night when accumulated heat is lost through the thin atmospheric blanket. In summer precipitation is light, averaging, at Paradise, 3.46 inches in June, .9 inches in July, and 3.44 inches in August. In the autumn the temperature, both daily and nightly, drops somewhat, and rain and cloudiness are the rule. At Paradise the average precipitation in September is 8.29 inches and in October 10.02 inches. The winter snows usually arrive by the middle of November.

Fig. 8. North side of Mount Rainier, 14,408 feet, with Mount Adams at left and Mount St. Helens at right. June 19, 1932. (Photo by 116th Photo Section, Washington National Guard, No. 011-36A-116.)

Trees that are characteristic of parts of the Hudsonian Life-zone include the alpine fir (Abies lasiocarpa), mountain hemlock (Tsuga mertensiana), Alaska cedar (Chamaecyparis nootkatensis) and white-barked pine (Pinus albicaulis). The following shrubs are listed by Jones (1938) as common in the Hudsonian Life-zone on Mt. Rainier: Salix barclayi, Salix commutata, Juniperus sibirica, Alnus sinuata, Ribes howellii, Lutkea pectinata, Potentilla fruticosa, Sorbus occidentalis, Spiraea densiflora, Pachistima myrsinites, Arctostaphylos nevadensis, Arctostaphylos uva-ursi, Cassiope mertensiana, Cassiope stelleriana, Phyllodoce empetriformis, Rhododendron albiflorum and Gaultheria ovalifolia.

There are extensive coniferous forests in the Canadian Life-zone, still lower on the mountain slopes. This is an area of lesser temperature extremes than is the Hudsonian Life-zone. The average annual temperature at Longmire, 2761 feet, Mt. Rainier, is 43.8°. The average temperature for the winter months, however, is below freezing. In July and August the temperatures are high, especially in the daytime. The eighteen year average for Longmire during these months is 60.6°. Snow is regular but the fall is lighter than in the Hudsonian Life-zone. The annual average, over a period of nineteen years, is 184.4 inches at Longmire. Precipitation is similar to that in the Hudsonian Life-zone, averaging perhaps slightly less.

In the Cascades the typical feature of the Canadian Life-zone is the extensive coniferous forest that extends, almost without a break, the entire length of the Cascades on both sides of the main crest. In addition to Douglas fir, the following trees occur in this forest: western hemlock (Tsuga heterophylla), amabalis fir (Abies amabalis), white pine (Pinus monticola) and noble fir (Abies nobilis). Other plants include Vaccinnium ovalifolium, Vaccinnium membranaceum, Menziesia ferruginea, Alnus sinuata, Acer circinatum, Sorbus cascadensis, Cornus canadensis, Clintonia uniflora, Stenauthium occidentale, Galium oreganum, and Prenanthes lessingii. Saprophytes abundant in, if not confined to, this zone are listed by Jones as: Monotropa uniflora, Monotropa hypopitys, Allotropa virguta, Newberrya congesta, Pterospora andromedea, Corallorrhiza maculata, Corallorrhiza mertensiana and Corallorrhiza striata.

West of the Canadian Life-zone in the western Cascades, the coniferous forests merge with the lowland forests of western Washington. To the east of the Canadian Life-zone in the eastern Cascades, there is a distinct change to a more arid climate and flora. At Leavenworth, 1167 feet, Chelan County, the annual average precipitation is but 19.5 inches and at Cle Elum, 1930 feet, but 23.23 inches. Temperatures are higher, the annual average of the above two localities being 47.2° and 45.4° respectively. The winter months are cold, with the average temperature in January and February below freezing. In summer the averages in July and August at Leavenworth are 68.8° and 68.0°, with the average maximum being 87.5° and 86.1°. Snowfall is heavy, the yearly average at Leavenworth being 98.5 inches and at Cle Elum 86.3 inches. The effect of this more arid climate is seen in the vegetation. The dense Douglas fir forest, is replaced by more open forests of yellow pine (Pinus ponderosus). Groves of oak (Quercus garryana) are found near streams. The open forests give way to the extensive grasslands bordering the desert. The transition of vegetation is similar to that occurring in the Yakima Valley Area.

In the Yakima Valley Area, arid conditions prevail. The average yearly precipitation at Yakima is 6.67 inches. Only in November, December and January may more than one inch of precipitation be expected monthly. Snow may be expected in the winter months and the yearly average snowfall is 22.1 inches. Winter temperatures are low, the average for December and January being but slightly above freezing. Summer temperatures are extreme; the July average is 73.1° and the average maximum for the same month is 89°. The highest temperature recorded is 111°.

The open pine forests of the eastern Cascades give way to grasslands. Grasses of several species are common but the bunchgrass (Agropyron spicatum) is most important. Other plants include the primrose (Oenothera pallida), lupines (Lupinus), and Mertensia. In ravines and near watercourses such shrubs as hawthorn (Crataegus douglasii), service-berry (Amelanchier cusickii, Amelanchier utahensis), aspen (Populus tremuloides), syringa (Philadelphus lewisii), snowberry (Symphoricarpos albus), choke-berry (Prunus melanocarpa) and elderberry (Sambucus caerulae) form thickets. Lower in the valley the vegetation is xerophytic, similar to that of the Columbian Plateau. Sagebrush (Artemisiae tridentata) is dominant. Other shrubs include rabbit brush (Chrysothamnus nauseosus, Chrysothamnus viscidiflorus), hop sage (Grayia spinosa), black sage (Purshia tridentata) and greasewood (Sarcobatus vermiculatus).

Fig. 9. Mount Rainier. Washington: Cowlitz Chimneys from base of Dege Peak, July 19, 1933. (Fish and Wildlife Service photo by Victor B. [Scheffer], No. 859.)

Climatic conditions in the Olympic Mountains are, in general, similar to those of the higher Cascade Mountains. There is a limited area of Arctic-alpine Life-zone on Mount Olympus. The principal life-zone is the Hudsonian. The Canadian merges with the lowland Humid-Transition and is difficult to ascertain as a separate zone. In the Hudsonian Life-zone the average temperatures are low. Winter climate is bitter and the snow lies deep. In the absence of government weather stations in the Olympics, detailed descriptions of climatic conditions can not be given. Vegetation of the Hudsonian Life-zone of the Olympic Mountains is, in general, similar to that of the same life-zone of the Cascades (see Jones, 1936, Botanical Survey of the Olympic Peninsula).

The lowlands of western Washington have a cool, humid climate. The average annual temperature of the area varies little from 50°. In winter the temperature, especially in January and February, commonly drops below the freezing point at night. Summer temperatures are moderate, rarely reaching 90°. Snowfall is light, averaging about 10 inches. The prevailing winds are from the west and are moisture-laden. They rise over the Olympic Mountains and loose heavy rains along the coastal area of the lowlands. The average annual precipitation at La Push, Clallam County, is 97.9 inches; at Clearwater, Jefferson County, 124.98 inches; at Aberdeen, Grays Harbor County, 81.58 inches; at South Bend, Pacific County, 83.35 inches. In contrast, the more inland areas receive less than half as much precipitation. The yearly average at Bellingham is 31.09 inches; at Seattle, 30.07 inches; at Tacoma, 39.53 inches; at Vancouver, Clark County, 37.24 inches.

The outstanding feature of the vegetation of western Washington is the coniferous forest. Previous to the logging activities a dense cover of Douglas fir, western hemlock and red cedar spread almost unbroken over the area. The openings in the forest and the marshy ravines and river valleys supported growths of underbrush and deciduous trees so dense and luxuriant as to compare with a tropical jungle. In the dense rain forests along the coast, mosses and lichens develop an understory vegetation many inches deep and clothe the branches of the forest trees. The mild temperature and excessive rainfall cause some species that usually are of bush or shrub size to reach the proportions of small trees. In some places one can climb twenty feet from the ground in a huckleberry tree, the trunk of which is five inches in diameter. The coniferous forest is made up of several species of trees. Most important among these are the western hemlock (Tsuga heterophylla), Douglas fir (Pseudotsuga taxifolia), and red cedar (Thuja plicata). Locally the western yew (Taxus brevifolia), lodgepole pine (Pinus contorta) and spruce (Picea sitchensis) may be common. Deciduous trees are numerous and include several willows (Salix sp.), aspen (Populus tremuloides), hazel (Corylus californica), alder (Alnus oregona), oak (Quercus garryana), broadleaf maple (Acer macrophyllum), vine maple (Acer circinatum), and flowering dogwood (Cornus nuttallii). Mosses and ferns are abundant. The sword fern (Polystichum munitum) and bracken (Pteridium aquilinum) are especially common. Space prevents listing all but a fraction of the typical shrubs but these include huckleberry (Vaccinium parvifolium, Vaccinium ovatum), Oregon grape (Berberis nervosa), salal (Gaultheria shallon), rose (Rosa gymnocarpa), thimbleberry (Rubus parviflorus), salmonberry (Rubus spectabilis), blackcap raspberry (Rubus leucodermis) and wild blackberry (Rubus macropetalus).

The higher parts of some of the ranges of northeastern Washington are in the Hudsonian Life-zone, but most of the mountains are in the Canadian Life-zone. The valleys are in the Transition Life-zone. Climatic conditions are similar to those of the eastern slopes of the Cascades. Winter temperatures are low, the average for December, January and February being below freezing. Summer temperatures are high, the July average for Colville being 67.2° and the July average maximum being 87.4°. Vegetation consists principally of coniferous forests in the mountains and deciduous woods in the valleys. Among the interesting features of the vegetation are the extensive stands of almost pure larch (Larix occidentalis). In most respects the flora closely resembles that of the Blue Mountains.

The Blue Mountains of southeastern Washington differ from other ranges in Washington in their relative aridity. There are few streams and a single river drains the area. There are no government weather stations in the Blue Mountains. The winter temperatures are low and the snow deep and lasting. Summer temperatures are high and humidity and precipitation low. Coniferous forests of the type of arid regions form the principal tree cover. Typical plant species include the white fir (Abies grandis), alpine fir (Abies lasiocarpa), larch (Larix occidentalis), spruce (Picea columbiana), and such shrubs as fool huckleberry (Menziesia ferruginea), Pachystima myrsinites, dogwood (Cornus canadensis), wild current (Ribes petiolare), mountain mahogany (Cercocarpus ledifolius), spirea (Spiraea sp.), lupines (Lupinus) of several species, maple (Acer douglasii), buckbrush (Ceanothus sanguineus), sticky brush (Ceanothus velutinus), and huckleberry (Vaccinium membranaceum).

Fig. 10. A "pothole" being crowded by drifting sand, ten miles south of Moses Lake, Washington, March 23, 1940. (Fish and Wildlife Service photo by Victor B. [Scheffer], No. 925.)

The Columbian Plateau and southeastern Washington present desert conditions. At Odessa, 1590 feet, Lincoln County, the average annual precipitation is only 9.38 inches, and only in the winter may more than one inch of precipitation per month be expected. The average temperature is 48.5°. In the winter the average is below freezing but in July it is 71.3°. The average maximum for July is 90° and an extreme of 111° is recorded. Walla Walla, 991 feet, has a higher annual precipitation (16.66 inches) but higher temperature (yearly average 53.5°, July average 75.0°, average July maximum 88.6°, extreme 113°). Winter temperatures on the Columbian Plateau are low. The January average at Odessa is 25.3° and at Walla Walla 32.4° The average yearly snowfall at Odessa is 19.4 inches and at Walla Walla 23.5 inches. Vegetation of the Columbian Plateau and southeastern Washington is of the desert type. A few pines and junipers grow in favored places. Along streams the cottonwood (Populus hastata) and willow (Salix) of several species are common. Most typical are grasses and shrubs such as the bunch grass (Agropyron inerme, Agropyron spictatum), foxtail (Alopecurus aequalis), cheat grass (Bromus tectorum), saltbrush (Atriplex truncata), greasewood (Sarcobatus vermiculatus) mustard (Arabis sp., Brassica sp.), sagebrush (Artemisia rigida, Artemisia tridentata), rabbit brush (Chrysothamnus nauseosus, Chrysothamnus viscidiflorus) and cactus (Opuntia polyacantha). The arid climate of the Columbian Plateau affects, to some extent, surrounding areas. Thus the Yakima Valley Area, the Columbia Valley, where it borders the Plateau, and the Okanogan Valley possess vegetation typical of the Columbia Plateau.

LIFE-ZONES AND ECOLOGY

The Transition Life-zone is the principal life-zone in Washington. It is divisible into three subdivisions: Humid, Arid-timbered and Arid-grasslands (Fig. 11) subdivisions. The Humid and Arid-timbered subdivisions of the Transition life-zone are closely related in some respects but different in others. They are separated by the Cascade Mountains. All of the Transition Life-zone west of the Cascades belongs to the Humid subdivision and the timbered Transition Life-zone east of the Cascades belongs to the Arid-timbered subdivision.

Fig. 11. Life-zones of Washington. Arctic-alpine not shaded. A. Hudsonian and Canadian (mapped together). B. Forested Transition (Humid and Arid subdivisions). C. Arid-grasslands of the Transition. D. Upper Sonoran.

The Arid-grasslands are of minor geographic extent. Although this subdivision is relatively distinct as concerns the distribution of plants, insects and birds, it is of little importance as concerns the distribution of mammals. For the most part, the mammals occupying it are more representative of surrounding areas. Large parts of the Arid-grasslands have been taken over for agriculture, especially wheat raising. Perhaps the greatest extent of the Arid-grasslands existing in a natural state is along the eastern Cascade Mountains and along the eastern side of the Columbian Plateau. These are truly transition areas, situated where the arid pine forests are replaced by open, sagebrush desert.

Fig. 12. Arctic-alpine Life-zone, Mount Rainier, Washington: Cowlitz Glacier from elevation of 9,500 feet. (Fish and Wildlife Service photo by Victor B. [Scheffer]. No. 900.)

The Upper Sonoran Life-zone includes the desert areas of Washington (figure 11 D). Its principal extent is the central Columbian Plateau. From the central Columbian Plateau, fingerlike projections of desert extend along the principal valleys.

The Arctic-alpine Life-zone occurs in the high Olympic Mountains and on the higher peaks of the Cascades. This is shown on the life-zone map, Fig. 11, as white, unshaded areas.

The mammalian faunas of the Hudsonian and Canadian life-zones resemble each other closely. The boundary between them is too complex to permit separating them on a small-scale map. Consequently they are mapped together on Fig. 11 as A.

The Humid Subdivision of the Transition Life-zone

This subdivision is remarkably uniform in composition over western Washington. The greatest difference is in precipitation. Rainfall along the coast is heavier than that in the interior. Consequently vegetation is more dense and luxuriant along the coast.

Four habitats may be distinguished in the Humid subdivision and further subdivision is possible. The dominant and most extensive habitat is the forest. Dominant mammalian species include: Peromyscus maniculatus, Sorex trowbridgii, Sorex obscurus, Tamiasciurus douglasii, Clethrionomys californicus, Aplodontia rufa, Glaucomys sabrinus and Odocoileus hemionus. Mammals are scarce and nocturnal forms prevail. As a rule, a line of mouse traps set in a forest habitat will take principally Peromyscus maniculatus with a few Sorex trowbridgii and Sorex obscurus and rarely a Clethrionomys californicus. In some places, especially where the moss is deep, a line of mouse traps will catch only shrews.

Fig. 13. Humid subdivision of the Transition Life-zone, Headley's Marsh, five miles east of Granite Falls, Washington, June 4, 1938. (Fish and Wildlife Service photo by Victor B. [Scheffer], No. 60.)

A second important habitat is the deciduous jungle. This differs from the forest habitat in that the dominant trees are of the deciduous type and in that understory vegetation, such as shrubs and annuals, is dense. The jungle habitat occurs in ravines and in valleys of streams and rivers and, in general, covers the lower, poorly drained portions of the Humid subdivision of the Transition Life-zone. Mammals are abundant and varied in the jungle habitat. The deer mouse (Peromyscus maniculatus) is the most common mammal but a line of mouse traps might also catch: Neurotrichus gibbsii, Scapanus orarius, Sorex vagrans, Microtus oregoni, or Zapus p. trinotatus. The mountain beaver, snowshoe rabbit, and Townsend chipmunk also occur there.

The prairies form a third habitat. These areas of native grasslands are of minor extent but are the principal home of several races of gophers and the Townsend mole (Scapanus townsendii). Deer and elk also browse on the prairies.

Fig. 14. Timbered arid subdivision of the Transition Life-zone, Kettle Falls on the Columbia River (now beneath Coulee Dam backwater), Stevens County, Washington, June 15, 1938. (Fish and Wildlife Service photo by Victor B. [Scheffer], No. 72.)

A fourth habitat is the marsh. In it there is here included the sphagnum bogs and marshy shores of lakes and streams. This habitat is characterized by damp ground, standing water, and dense vegetation. Typical mammalian species include the water shrew (Sorex bendirii), Townsend meadow mouse, muskrat and mink.

Other habitats, such as aerial for the bats and aquatic for the beaver and otter, might be listed.

The Arid Timbered Subdivision of the Transition Life-zone

In Washington the Arid timbered subdivision of the Transition Life-zone is the open, pine forest. Because of the aridity of this habitat, marshes and streamside thickets are uncommon, but where habitats of this kind do occur they have a fauna distinct from that of other habitats.

The pine forest habitat includes many diurnal species, such as the red squirrel, yellow-pine chipmunk, and Columbian ground squirrel. The white-tailed deer occurs here and, for most of the year, the mule deer. Snowshoe rabbits are usually present. Near rocks the bushy-tailed wood rat is common. Mice are scarce, probably because of the open nature of the surface of the ground. A night's trapping usually yields only a few Peromyscus maniculatus.

The mammalian fauna of the marshes and streamside thickets is similar. Shrews including Sorex vagrans and Sorex obscurus are uncommon. Meadow mice, including Microtus pennsylvanicus, Microtus longicaudus, and more rarely Microtus montanus, are taken.

The Arid Grasslands Subdivision of the Transition Life-zone

This subdivision is so much utilized by man where it occupies any considerable areas, and is of such a transitional nature elsewhere, that it is important for only a few native wild mammals. The sagebrush vole (Lagurus curtatus) seems to be confined to the arid grasslands. The white-tailed jack rabbit is now found principally in the arid grasslands, but its confinement there has resulted probably from competition with the black-tailed jack rabbit. The montane meadow mouse (Microtus montanus) is the only common, representative species. Many species from the Upper Sonoran Life-zone extend into the arid grasslands where conditions are suitable. These include Reithrodontomys megalotis, Perognathus parvus, Citellus washingtoni and Marmota flaviventris. A few species more typical of the Arid timbered subdivision of the Transition Life-zone stray onto the arid grasslands. Citellus columbianus and Microtus longicaudus may be included here.

The Upper Sonoran Life-zone

The sagebrush desert in Washington is relatively uniform in nature. Several different habitats may be distinguished, such as sandy areas, open sage, dense sage, stony ground, and talus. Qualitatively, however, the mammalian fauna of these areas is surprisingly similar. Quantitatively, there are great differences. For example, the grasshopper mouse is rare in the open sage areas with hard, claylike soil but common on drifted sand. The harvest mouse is common in dense sage but rare in open sage or in open, sandy areas. Mammals are abundant on the sagebrush desert and typical species include: the black-tailed jack rabbit, Nuttall cottontail, Ord kangaroo rat, Great Basin pocket mouse, Townsend ground squirrel, Washington ground squirrel.

Marshes are not uncommon on the Columbian Plateau and elsewhere in the Upper Sonoran Life-zone in Washington. They do not possess a fauna that is strictly Upper Sonoran but instead contain species more typical of the Arid-timbered subdivision of the Transition Life-zone. Meadow mice found in desert marshes include Microtus montanus and Microtus pennsylvanicus. The only shrew we have found is Sorex vagrans. The harvest mouse (Reithrodontomys megalotis) is often abundant in marshes.

Fig. 15. Upper Sonoran Life-zone, sand and basalt cliffs along the east bank of the Columbia River, at Vantage, Washington, 1930. (Fish and Wildlife Service photo by Victor B. [Scheffer], No. 848.)

The Canadian Life-zone

The Canadian Life-zone is a relatively uniform area in which the forest habitat is most important. Talus and swift, cold streams bring some typical mammalian species into the Canadian Life-zone from the Hudsonian. Mammals are usually common; they are abundant only in the upper portion of the Life-zone. Arboreal species and forms adapted to life beneath the forest cover are dominant. The Douglas squirrel, red squirrel, northern flying squirrel and Townsend chipmunk are typical arboreal species. Traps set beneath the trees might catch Peromyscus maniculatus, Clethrionomys gapperi, Neotoma cinerea, Sorex obscurus, or Sorex trowbridgii.

Fig. 16. Canadian Life-zone forest on Mount Rainier, Washington, elevation 2,800 feet, September 14, 1934. Western hemlock, Douglas fir, western red cedar, and grand fir. (Fish and Wildlife Service photo by Victor B. [Scheffer], No. 325.)

The Hudsonian Life-zone

In Washington the Hudsonian Life-zone is of greater diversity than any other. Frost and steep slopes have formed great masses of talus and, in this talus, certain species of mammals, such as Ochotona princeps, Marmota caligata and Marmota olympus are found. Other species, such as the golden-mantled ground squirrels, mountain chipmunk, bushy-tailed wood rat, red-backed mouse and long-tailed meadow mouse find the talus an ideal home. Glacial action has produced, in the Hudsonian Life-zone, numerous level or concave areas that contain small lakes and slow-moving streams. Dense, herbaceous vegetation is abundant nearby. Small mammals abound and a line of mouse traps will almost certainly catch a few such typical species as: Sorex palustris, Sorex obscurus, Microtus oregoni, Microtus richardsoni, Microtus longicaudus and Zapus princeps as well as the ever present Peromyscus maniculatus. The shrew-mole or heather vole might also be taken, though the latter is more apt to be found in nearby heather meadows.

Table 1. Distribution of mammals in Washington by Life-Zones.
A. Abundant. C. Common. R. Rare.

GEOLOGIC HISTORY OF WASHINGTON

The composition of the mammalian fauna of any area is dependent on several factors. These include the composition of the original fauna, species which have since invaded the area, and quantitative and qualitative changes that have occurred in the area. The latter two factors refer to changes in relative numbers or extermination of species through environmental changes or competition with other forms and evolutionary changes that have occurred in the species making up the mammalian fauna.

Our knowledge and understanding of the distribution and history of the species of mammals occurring in Washington decreases rapidly as we go back in time. The distribution of the modern fauna at the present time is fairly well known. The distribution of species 100 years ago is less well understood. This is especially true of certain game species and carnivores whose distribution has been altered by man. Our knowledge of the distribution of mammals in the Pleistocene and earlier times is based on fossil skeletons. Such knowledge must necessarily be meager, for conditions favorable to fossilization and the preservation of fossils until their subsequent discovery by man, were not of common occurrence.

In the Cascades and in eastern Washington, the Miocene was a time of orogeny and great volcanism. Great flows of lava, 4,000 feet thick in the Snake River area ([Russell], 1893), emerging from fissures in the Snake River area, formed the Columbian Plateau. The Columbian basalt slopes inward centripetally from the eastern, northern, and western margins of the Columbian Plateau with an average descent of 25 feet to the mile ([Flint], 1938). The dip of the lava flows results in the basalt-marginal course of the Spokane and Columbia rivers today, along the northern edge of the Columbian Plateau. The earlier part of the Pliocene was a period of erosion and deformation. In the early Pleistocene the five great volcanic cones of the Cascades, Mount Baker, Glacier Peak, Mount Rainier, Mount Adams and Mount St. Helens were formed. In eastern Washington a gentle folding of the Miocene lava flows occurred. The folding took place slowly and the Columbia River in its course along the eastern edge of the Cascades cut through the folds as they formed, making a series of water gaps. Farther south, the Simcoe-Frenchman Hills anticline seems to have arisen more rapidly and the Columbia River was forced eastward before it became impounded and rose over the barrier and plunged down, tearing out the great Wallula Water Gap ([Flint], 1938). This gap is a mile wide, eight miles long and, in places, a thousand feet deep. The impounding of the Columbia by the Simcoe-Frenchman Hills anticline resulted in a lake several hundred miles in area. Sediments deposited in this lake form the Ringold formation. The Ringold formation possesses a very early Pleistocene mammalian fauna.

The Pleistocene was a time of great change in the mammalian fauna of the world. Unfortunately the beautiful glacial sequence revealed in Europe and the Mississippi Valley cannot be detected in Washington. In western Washington the deposits of the last continental glaciation and fluvial deposits of the last interglacial period almost everywhere obscure evidence of earlier glaciations. Deposits of an earlier glaciation, named Admiralty by [Bretz] (1913), have been detected in places. Deposits of greater age, that may represent a still earlier glaciation, have been noted. In eastern Washington the only definite proof of multiple glaciation is of one glaciation preceding the last. This is the Spokane glaciation of [Bretz] (1923). That multiple glaciation in the sequence reported from the Mississippi Valley affected Washington seems probable. The lack of evidence of a complete sequence is negative evidence. In western Washington the earliest glacial deposits might be beneath the later deposits or they may have been removed or reworked by subsequent glaciations, whereas in eastern Washington they may have been removed by subsequent glaciation and erosion.

The time interval between the two known glaciations appears to have been of greater duration than the Recent. The drift of the earlier period is sometimes found covered by the till of the later glaciation, and preserved by it. The early material is deeply weathered and all save the hardest pebbles and quartzites, for example, are rotten and disintegrate at the touch. In contrast, the later deposits are almost unweathered. Pebbles are hard, and ring when struck. A zone of leaching and oxidation of the finer materials reaches a depth of some 30 inches, below which the till is fresh.

Two names are currently applied to the last continental glaciation of the state of Washington. That west of the Cascade Mountains, studied and described by [Bretz] (1913), was termed "Vashon." The interglacial cycle preceding it was called "Puyallup." The glaciation of eastern Washington has been called "Wisconsin," after the Mississippi Valley terminology, by several writers. Papers by [Flint] (1935, 1937) describe and map it.

The Vashon and Wisconsin glaciations probably occupied the same time interval, although this has not certainly been established. In the present report I have used the term "Vashon-Wisconsin" in speaking of the entire period, or the glaciers both east and west of the Cascades together. Vashon, alone, is restricted to western Washington and Wisconsin to eastern Washington.

Fig. 17. Extent of Vashon-Wisconsin ice over Washington. The Wisconsin and Vashon glaciers have been connected through the Mount Rainier section of the Cascades because it is thought that few or no mammalian species lived in the Cascades north of Mount Rainier while the ice was in place. Data generalized from [Flint] (1937), [Bretz] (1913), [Culver] (1936) and other sources.

The Vashon glaciation seems to have consisted of an ice dome centering in Puget Sound (the Puget Glacier of [Bretz], 1913) and flooding the lowlands from the Olympic Mountains to the Cascade Mountains. The southern edge of the Puget Glacier was slightly south of the present terminus of Puget Sound. Fingerlike projections of ice were forced up valleys of the western Cascades and the northern and eastern Olympics. Some of these upward moving fingers of ice met and coalesced with valley glaciers descending from the mountains. At the southern edge of the glacier, the Black Hills and Porcupine Hills remained above the ice although partially surrounded by it.

The Wisconsin glacier, according to [Flint] (1935), was a great piedmont glacier, fed by valley glaciers from the Cascades and Coast Ranges to the west and the Rockies to the east. It extended from the Idaho boundary to the Cascade Mountains. From the Canadian Boundary it sloped down to an approximate elevation of some 6500 feet at Republic and to 2500 feet on the northern edge of the Columbian Plateau which was the southern edge of the glacier. The Kettle River Mountains, in almost the center of the glacier, remained a peninsula or driftless area that divided the glacier into two lobes. The Pend Oreille, Huckleberry and other mountain ranges, formed nunataks, or islands above the ice, at the southern part of the glacier.

The behavior of valley glaciers in the northern Cascade Mountains during Vashon-Wisconsin time, seems to have been variable. Some depression of the snow line, at least in the north, seems probable.

The Vashon Glacier impinged on the eastern, northern and to some extent the western, slopes of the Olympic Mountains. Late Pleistocene valley glaciers in the Olympics, however, seem to have been inconsequential.

The time of the retreat of the Vashon-Wisconsin glaciers is a subject of special interest to the mammalogist in that it represents time for invasion and dispersal of species and in that it represents generations of individuals upon which natural selection might act. It is generally agreed that a period of approximately ten thousand years has elapsed since the retreat of the Vashon-Wisconsin glaciers from Washington.

Information on the climate of the state of Washington previous to the period of the last continental glaciation is understandably meager. [Bretz] (1913) considers the Puyallup period a time of excessive precipitation and erosion. Bits of lignite from Puyallup sediments seem to be of Douglas fir. Presumably the climate was slightly warmer and more humid than it is today. Vegetation possibly consisted of coniferous forests.

With the advance of the Vashon ice, mammals north of the ice border were all or mostly eliminated. Climatic conditions south of the border of the ice probably were strongly affected by it. Remains of mammoths have been found in Vashon till. The presence of many non-boreal species of mammals in southwestern Washington indicates their persistence there and that conditions therefore were not intolerable for them. Probably the climate of southwestern Washington was cool and dry. Fir, spruce, and Douglas fir may have been the dominant trees. Hansen (1941 A: 209) found evidence from studies of pollen that coniferous forests were growing in west-central Oregon in late glacial time. These pollen studies of postglacial peat bogs by Henry P. Hansen give evidence of postglacial climatic changes. Hansen points out (1941 B, 1941 C) that climatic changes west of the Cascades were probably slight because of the influence of the Pacific Ocean. Pollen profiles indicate an early, cool, dry climate followed by a warmer one and increasing humidity. The present climate may be considered cool and humid. Most of western Washington lies in the Humid subdivision of the Transition Life-zone.

Fig. 18. McDowell Lake, Little Pend Oreille Wildlife Refuge, Stevens County, Washington, September 29, 1939. (Fish and Wildlife Service photo by Victor B. [Scheffer], No. 730.)

The pre-Wisconsin climate of eastern Washington is unknown. From the loessial nature of the Palouse Soil ([Bryan], 1927), a preglacial deposit, the area would seem to have been arid, probably a grassland or a sagebrush desert. If the fossil fauna discovered at Washtuckna Lake, Adams County, is of this period, the forest conditions of the Blue Mountains were slightly more extensive than at present. The glacial climate of the Columbian Plateau in Wisconsin time was probably cool and arid. Pollen studies by Hansen (1939, 1940) indicate increasing dryness and warmth since the retreat of the Wisconsin ice. Present-day climate on the Columbian Plateau is warm and dry. The plateau is principally a sagebrush desert. The glaciated area to the north is cooler and more humid, supporting extensive forests of yellow pine and other conifers.

THE FAUNAS

We have mentioned elsewhere that three different mammalian faunas occur in Washington. These may be described as follows.

1. The Great Basin Fauna. This fauna is best typified by such genera as Perognathus and Dipodomys. Species that, at least in Washington, are confined to this fauna are:

The break between the Great Basin Fauna and the other two faunas is extremely sharp, probably as a consequence of a sharp break in the flora.

2. The Pacific Coastal Fauna. The mammals of the humid coastal district range from the Fraser River, British Columbia, southward to the vicinity of Monterey Bay, California. In Washington typical genera are Aplodontia, Neurotrichus and Scapanus. The following species are typical of the Pacific Coastal Fauna in Washington:

Some species which range outside this faunal area have strongly marked races confined to it. Glaucomys sabrinus oregonensis and Lepus americanus washingtonii are examples. The Pacific Coastal Fauna is a forest fauna. Like the Great Basin Fauna, it reaches its northern limit of distribution in Washington and is better represented farther south. Unlike the Great Basin Fauna, the break between the Pacific Coastal and the surrounding fauna is not sharp, because forests continue into the more boreal faunal areas to the north and east. There, some mingling of coastal and Rocky Mountain faunas occurs.

3. Rocky Mountain Fauna. If this fauna be thought of as including mammals of the Rocky Mountains of the United States, and also those of the subarctic faunal area to the east of these mountains in Canada, the species in Washington are as follows:

Of the three, the Great Basin Fauna is the most distinct. Only about twenty species which occur within the Great Basin Faunal Area, occur also outside of it in one or both of the two other faunal areas. Most of these twenty are subspecifically different in the Great Basin Faunal Area as contrasted with one or both of the other areas. Each of the other two areas has no less than 32 species that are not restricted to it.

SPECULATION AS TO EMIGRATIONAL
HISTORY OF THE MAMMALS

The present fauna of the state of Washington was derived in part from Asia and in part from native forms. Great changes occurred in early Pleistocene through emigration. By the late Pleistocene most of the mammals now occurring in the state of Washington were as they are today. The greatest changes that seem to have occurred in the late Pleistocene are the extinctions of numerous groups, locally or totally. Among the carnivores, [Matthew] (1902: 321) reports remains of the great lion, Felis atrox, associated with such familiar species as the badger, cougar, lynx and mountain goat. The great lion was very similar to the modern African lion but was fully a fourth larger. Associated with the great lion in the California tar pits are the carnivorous short-faced bears (Tremarctotherium), as large as the Alaskan brown bears; dire wolves (Aenocyon), larger than timber wolves; and saber-tooth tigers (Smilodon). These forms were probably also present in Washington in the late Pleistocene. [Matthew] (loc. cit.) reports remains of the giant beaver, Castoroides, from the Silver Lake deposit of Oregon. This great beaver, as large as a black bear, was doubtless a resident of Washington also. Peccaries, camels, bison, horses and giant ground sloths have been recorded from Pleistocene deposits of Washington and nearby areas. Of the elephant tribe, the mastodon and several species of mammoths were present.

These extinct forms have doubtless exerted some influence on the past distribution of mammals in Washington and possibly have had an effect on the distribution of members of the living fauna. One species of the mammoth, at least, existed in Washington in postglacial time. Remains of this form, Elephas columbi, have been found in Vashon till.

The three faunas of Washington can be placed in two categories. One is Sonoran, essentially a desert type, and occupies the Columbian Plateau. The other two are forest faunas, predominantly boreal in complexion, and are closely related. The Rocky Mountain Fauna is found in the Blue Mountains and in northeastern Washington. The Pacific Coastal Fauna is found in western Washington.

The ice sheets of Vashon-Wisconsin time descended southward to southern Puget Sound and to the northern edge of the Columbian Plateau. If the area of the ice sheet be superimposed on a map of distributional areas of Washington, it is seen that the area occupied by the Rocky Mountain Fauna in northeastern Washington is eliminated. Thus, at the maximum descent of Wisconsin ice, the Rocky Mountain type of mammalian fauna was found only in extreme southeastern Washington. No point of contact between the forest fauna of the Rocky Mountains and the fauna of the Pacific coast exists, anywhere, because desert areas, or at least barren plains, lie between them from the border of the glaciers south to Mexico. For the entire period, perhaps thousands of years long, while the glaciers were in place, the two forest faunas were separated. Repeated separation of the faunas by successive glaciations is thought to be responsible for many of the differences now existing between them.

Following the retreat of the ice, the Pacific Coastal Fauna extended its range northward to the Fraser River and, in part, into the Cascade Mountains. The Rocky Mountain Fauna invaded northeastern Washington and boreal Canada, including the Pacific Coast north of the Fraser River. Certain parts of the Rocky Mountain Fauna also invaded the Cascade Mountains.

Inasmuch as the Cascades were invaded by species from both faunas, a detailed analysis of the mammals existing there now seems justified. Several significant features of the composition of the mammal fauna of the Cascades are apparent. First, several species typical of the Pacific Coastal Fauna are present, such as Neurotrichus gibbsii, Sorex trowbridgii, Sorex bendirii, Tamias townsendii, Microtus oregoni and Aplodontia rufa. Each of these species has no close relatives in the Rocky Mountain Fauna and, save perhaps Sorex trowbridgii, occupies a unique ecological niche and has no counterpart in the Rocky Mountain Fauna.

A second group includes species with close relatives in both the Rocky Mountain and Pacific Coastal faunas. This group is remarkable in that it is composed of either very closely related species or very strongly differentiated subspecies in each fauna. For example, the golden-mantled ground squirrel (Citellus saturatus) of the Cascade Mountains is specifically distinct from Citellus lateralis. Supposedly the Cascade form was isolated in the southern Cascades during Vashon-Wisconsin time. The Douglas squirrel (Tamiasciurus douglasii) of the Cascades, which has a red belly, is the same as the squirrel of the lowlands of western Washington but is specifically distinct from the red squirrel (Tamiasciurus hudsonicus) of the Rocky Mountain Fauna, which has a white belly. In the extreme northeastern Cascades the two species come together. They do not interbreed but seem to compete, for they do not occur together. The flying squirrel (Glaucomys sabrinus fuliginosus) of the Cascades is only slightly differentiated from other races of the Rocky Mountain Fauna but is much different, as are all Rocky Mountain races, from the western Washington subspecies (Glaucomys s. oregonensis). The red-backed mouse of the Cascades is Clethrionomys gapperi, a species distinct from Clethrionomys californicus of western Washington. The jumping mouse of the Cascades is Zapus princeps trinotatus, the same race that occurs in western Washington. It is quite distinct from, and has previously been considered a species separate from, the races of the Rocky Mountain Fauna. The snowshoe rabbit of the Cascades is closely related to other races of the Rocky Mountain Fauna but is distinct from L. a. washingtonii of western Washington. The pika (Ochotona princeps) of the Cascades was apparently isolated in the southern part of the range during the glaciation. After the retreat of the glaciers it extended its range northward. Competition between two subspecies has resulted in parallel distributions due to relative body size. The two races freely intergrade and the differences between them are not so great as in the other forms mentioned.

The third group of mammalian species of the Cascades is composed of species typical of the Rocky Mountain Fauna such as: Marmota caligata, Synaptomys borealis, and Orcamnos americanus. Each has no ecological counterpart in the Pacific Coastal Fauna. Each is absent from the Cascades of Oregon.

We interpret the mixture of faunas in the Cascades as follows: The Vashon-Wisconsin ice sheet was in place for a long period of time, longer, probably, than the Recent. During this time, forest mammals of the Pacific Coast were isolated from forest mammals farther east by glaciers to the north and desert to the east. Changes took place in both of the separated forest faunas. Certain species, perhaps, such as the mammoth, became extinct. Other forms were exterminated then or at an earlier time in one fauna or the other. If Aplodontia, Neurotrichus or Scapanus occurred in the Rocky Mountain faunal area, it lived in an inland area of rigorous climate, and disappeared there because it was unable to adapt itself to the cold. In the mild climate caused by proximity of the ocean, mild even in Vashon-Wisconsin time to judge from evidence yielded by study of fossil pollens, primitive forms such as moles, the Bendire shrew, and mountain beaver persisted along the coast, where there were no boreal conditions. Some alpine forms, such as Marmota olympus, Ochotona princeps brunnescens and Citellus saturatus persisted in the Olympic or Cascade mountains as relic species. On the whole, however, the glacial divergence resulted in a boreal forest fauna and a temperate forest fauna.

In addition to change in component species, there were evolutionary changes in the species themselves. In some these were considerable, as shown by the differences between related forms of the two faunas. In most species, however, evolutionary changes have resulted in only subspecific differences.

Following the retreat of the glaciers and the establishment of vegetation on the deglaciated areas, movements of the faunas occurred. The Rocky Mountain Fauna spread northward and westward, to northeastern Washington and, in Canada to the Pacific, occupying most of the land exposed by the glaciers. The Pacific Coastal Fauna spread northward only as far as the relatively slight barrier of the Fraser River. The Cascade Mountains became a "no-man's land." The pika and golden-mantled ground squirrel of the southern Cascades spread northward. Boreal Rocky Mountain forms with no ecologic competitors from the Pacific Coastal Fauna occupied the Cascades. Also, coastal species with no Rocky Mountain competitors occupied the Cascades. Nevertheless, some competition between members of the two faunas ultimately occurred, and in instances where closely related forms occurred in the two faunas, one or the other prevailed in the Cascade Range. For example, the Douglas squirrel and big jumping mouse are now established in that range, but the relative of each occurring in the Rocky Mountains is present in the extreme northeastern Cascades. It is possible that in these two cases, the related form occurring in the Rocky Mountains has just entered the area and that competition has just begun. With regard to the flying squirrel, red-backed mouse and snowshoe rabbit, the more boreal Rocky Mountain representatives have definitely displaced the coastal forms.

Certain mass movements of mammals are popularly believed to have occurred with the advance of the ice sheets of the Pleistocene. The boreal birds and plants on higher peaks of the Cascades and the Sierra Nevada of California are thought to represent relics of faunas that moved northward. Such mass movements probably did occur and there is some evidence of their occurrence in Washington. Probably the pre-Wisconsin flora of coastal British Columbia consisted of coniferous forest similar to that of western Washington today. If this were the case, the mammalian species in British Columbia corresponded closely to those of western Washington. An influx of such a fauna into coastal Washington would scarcely be evident today if, indeed, it was noticeable even then. In eastern Washington, forest species forced southward would come upon the barren, inhospitable plains and deserts of the Columbian Plateau.

The greater part of the southward moving forms found refuge in the Cascade Mountains where, for most of Wisconsin time, they were isolated in the southern Cascades. Examples are Sorex palustris, Martes caurina, Martes pennanti, Gulo luscus, Vulpes fulva, Lynx canadensis, Tamias amoenus, Thomomys talpoides (douglasii group), Phenacomys intermedius, Microtus richardsoni and Ochotona princeps. In each of these species little or no subspecific variation has occurred between the populations in the Cascades of Washington and the Cascades of Oregon.

While the ice sheet existed in Washington there may have been relatively little movement of the mammalian fauna. There is definite evidence of a brief contact between the Rocky Mountain Fauna of the Blue Mountains and the fauna of the southern Cascades. For example, the pocket gopher of southeastern Washington (Thomomys talpoides aequalidens) is most closely related to the gopher of the Simcoe Anticline, and the long-tailed meadow mouse (Microtus longicaudus halli) of the Blue Mountains closely resembles the meadow mouse of the Yakima Valley.

Mammals of the Blue Mountains and those of the southern Cascades may have come into contact on the Simcoe-Horseheaven Hills Anticline, which now stretches 150 miles from the Cascades to the Wallula Water Gap. Excepting the easternmost 40 miles, it is timbered. East of the Columbia, a continuation of the anticline and other hills reaches to the Blue Mountains. Supposedly, in Wisconsin Time, this anticline possessed a more humid climate and the habitat was essentially the same as that of an alpine meadow today. The forms on the two ends of the anticline that are closely related inhabit humid, meadow habitat. In an earlier paper, [Dalquest] and [Scheffer] (1944: 316) named this connection the Simcoe Bridge. Its existence was so strongly indicated by the distribution of pocket gophers in Washington that we supposed that the study of many other species would show that they crossed this bridge. However, study of additional species shows that for them the Simcoe Bridge was of only slight importance; there appears to have been but little mingling of the fauna of the Blue Mountains and the Cascades by way of the bridge. The Columbia River probably acted as an effective barrier to many forms that might otherwise have utilized it. The forms that did cross on this bridge are species known to be active in winter and to emigrate over considerable areas through tunnels under the snow ([Davis], 1939: 257). The pocket gopher and long-tailed meadow mouse may have crossed the Columbia, under a cover of snow, when the river was frozen over. The Columbia has frozen over at the Wallula Water Gap in historic times.

Fig. 19. Pend Oreille River (or Clark Fork of the Columbia) from a point near Newport, Washington, looking south, June 13, 1938. (Fish and Wildlife Service photo by Victor B. [Scheffer], No. 67.)

Great movements of mammal species came after the retreat of the Vashon-Wisconsin ice. The greatest of these was the spread of the Rocky Mountain Fauna northward and eastward to the Pacific. In this process, northeastern Washington was inhabited by animals that probably came from Idaho and Montana. Some of the species from farther north, as for example the caribou, may first have been forced into Idaho and Montana by the glaciers. The invasion of northeastern Washington probably was not a mass movement of an entire fauna, because invasion seems to be still going on. As yet the woodchuck and striped ground squirrel of the Pend Oreille Mountains have not crossed the Columbia River, a relatively minor barrier in northeastern Washington. The mountains west of the Columbia are occupied instead by the yellow-bellied marmot, a member of the Great Basin Fauna, and there is no ecologic counterpart in these mountains of the golden-mantled ground squirrel.

Also the invasion of the Cascade Mountains by a number of Rocky Mountain species may have been an intermittant or gradual movement. The red squirrel and Rocky Mountain subspecies of jumping mouse now are present in the extreme northeastern Cascades, where they possibly arrived relatively recently. The squirrel is competing with the coastal species already present and may eventually supplant it. The same may be true of the two forms of jumping mouse.

The invasion by the Rocky Mountain Fauna was rapid as compared with that of the Pacific Coastal Fauna. Evidence of this was presented in an earlier paper ([Dalquest] and [Scheffer], 1944: 310), where it was shown that the gophers of the douglasii group, isolated during the Vashon time in the southern Cascades, made only a few feeble postglacial movements and then only when conditions were ideal. In this same time the fuscus group of gophers moved from Idaho and virtually surrounded the range of the douglasii group. This tendency to immobility seems to have been characteristic of every member of the Pacific Coastal Fauna. If the retreat of the Vashon and Wisconsin glaciers occurred at the same time, both faunas had an equal opportunity to invade the deglaciated area. Yet, the Pacific Coastal Fauna actually moved northward along the coast only to the Fraser River area, and slightly farther in the Cascades.

Possibly the two glaciers retreated at different times. The Wisconsin Glacier was a piedmont glacier, fed by valley glaciers to the west and east, and may have disappeared when the feeder glaciers dried up. The Vashon Glacier was instead an ice cap, supposedly self-supporting much in the same manner as is the Greenland Ice Cap, and may have persisted longer than the Wisconsin glacier. If it did persist longer it formed a barrier to the northward emigration of coastal species of mammals.

Possibly, also, the whole of the Pacific Coastal Fauna possessed an inherent sluggishness resulting from their long residence in the uniform climate and habitat of the Pacific Coast. Certainly the species show today great habitat specialization as compared with species of the Rocky Mountain Fauna. Also, there are fewer individual mammals per unit of area in western Washington than in northeastern Washington. The persistence of the Vashon Glacier, an inherent lack of incentive to emigrate, or retention of a favorable environment, may account for the relatively small area invaded by the Pacific Coastal Fauna.

The Olympic Mountains, on the Olympic Peninsula, rise above the timber-line and are surrounded by forested lowlands which in a sense isolates this mountain range. Early workers, notably [Elliot], obtained specimens of mammals from the Olympics and described numerous races, principally, it appears, on the supposition that because the range was somewhat isolated it should possess a unique fauna. Subsequent revisions of groups of mammals have indicated that most of the names proposed, on the basis of specimens from the Olympics, were either invalid or pertained to mammals found also in the Cascades.

The mammals of the Olympic Peninsula appear to be divisible into three groups. A majority of them fall within the first group, namely coastal races possessing wide ranges in the lowlands of western Washington. The second group consists of species of the Rocky Mountain Fauna but with close relatives in the Cascades. The third group includes but two forms, both unique and found only on the Olympic Peninsula.

The first group includes nonalpine forms of the lowlands surrounding the Olympic Mountains. For the most part these are identical with races of the Puget Sound area. A few are slightly differentiated from the mammals of the Puget Sound area but are the same as mammals from southwestern Washington. As will be shown later, some differentiation in the Pacific Coastal Fauna has occurred. This is thought to be evolution in situ, rather than the result of mass movements. Many nonalpine Coastal mammals occur in alpine habitat in the Olympics.

The second group consists of species of the Rocky Mountain Fauna. Their relationship to the mammals of the Cascades is indicated in the two parallel columns below.

Only two of these are racially distinct from their relatives in the Cascades. Of these the chipmunk is a plastic species and breaks down into many races in Washington. The chipmunks of the Olympics and of Mt. Rainier are so similar that [Howell] (1929: 77) considered them as identical and mapped Mount Rainier as an isolated part of the range of the Olympic form (see account of T. a. caurinus). The relationship of the red-backed mice, also, is close, but has been obscured by the usual assumption of relationship between californicus (occidentalis) and gapperi. The principal difference between the alpine forms is the pallor of nivarius. This pallor of mammals in general from the Olympic Mountains is noteworthy, but in the red-backed mouse is exceptionally noticeable. This pallor is discussed beyond in the paragraphs dealing with differentiation. Mention should be made here of Myotis keenii. This is a species which seems to have extended its range to Washington from the north. The power of flight, of course, removes it from consideration in attempting to reconstruct routes followed by terrestrial mammals.

The route of the pocket gopher (Thomomys) in emigrating from the Cascades to the Olympics ([Dalquest] and [Scheffer], 1944: 310), was over the outwash train of the Mount Rainier Glaciers, especially the Nisqualli Glacier, to the extensive outwash aprons of the Vashon Glacier around southern Puget Sound, and thence into the Olympic Mountains. Under the conditions in early postglacial time this invasion route, hereinafter termed the Puget Bridge, around the Pleistocene Lake Russell (present Puget Sound), is thought to have been mainly an alpine meadow. Indeed, the isolated prairies remaining today are the unforested remnants of the outwash aprons (see [Dalquest] and [Scheffer], 1942: 69) and possess several species of alpine plants, notably the shooting star, camas, and bear grass.

If the Vashon Glacier remained in place considerably longer than the Wisconsin Glacier, these Rocky Mountain species may have invaded the Cascades from northeastern Washington and travelled around the southern edge of the Puget Glacier or of Lake Russell. The close relationship of the races involved, however, suggests that the emigration took place much more recently. The barriers to such movement even today are slight, consisting principally of narrow areas of forest. For the water shrew, an almost continuous water habitat still exists, by way of the Nisqualli River, streams in the Puget Sound area, and the Satsop River in the Olympics. Tree-living forms such as the fisher and marten might easily travel the intervening distance today, and, by going along the forests north of the Chehalis River, reach the Olympics without crossing more than small streams and virtually without descending to the ground. Chipmunks and mice probably utilized the prairie or meadow area of the Puget Bridge, as did the gophers.

Considering the long existence of the Puget Bridge, it is surprising that such forms as the pika, water rat and golden-mantled ground squirrel did not cross to the Olympics. These forms are, however, species of the higher or eastern slopes of the Cascades.

The third group of Olympic mammals includes the white-bellied water shrew and the Olympic marmot, both indigenous forms.

The Bendire water shrew, Sorex bendirii albiventer, is not restricted to alpine habitat but occurs throughout the Olympic Peninsula. Its nearest relative is S. b. bendirii of the rest of western Washington. S. b. albiventer differs from bendirii only in possessing a partially white ventral surface. We can only conclude that the white belly of albiventer is a mutation that the local environment has favored and that the characters have, therefore, spread through the population on the Olympic Peninsula. Occasional specimens are taken with dark bellies characteristic of bendirii ([Jackson], 1928: 199).

The Olympic marmot, Marmota olympus, specifically distinct, and apparently the only preglacial relic species of alpine mammal in the Olympics, is most nearly related to Marmota vancouverensis of the unglaciated mountains of Vancouver Island, British Columbia. Both olympus and vancouverensis are close relatives of Marmota caligata which ranges southward into the Cascades of Washington.

The Columbia River in its course westward through the Cascade Mountains, might be expected to act as a highway for the movement of mammals, but the extent to which it has done so seems to be slight, at least in postglacial time. The pocket gopher of southwestern Washington reached the area about Vancouver from the southern Cascades by way of meadows on the gravel terraces of Wisconsin glacial drift. No other mammal seems to have extended this far. Several Great Basin species, such as the cottontail, extend westward in the valley of the Columbia to the vicinity of Bingen.

The mammals of western Oregon and southwestern Washington are closely similar as are the plants and climate, despite the fact that the broad Columbia River courses through the area and did so all through Recent and Pleistocene times. Many species would be expected to have crossed this barrier by swimming and rafting, and that they did so is indicated by the large number of mammals which are identical or very closely related on the two sides of the river.

Mammals which seem not to differ on the two sides of the river include:

The following mammals are subspecifically distinct in western Washington and western Oregon:

The following species are found in western Oregon but do not occur in western Washington:

Several of these mammals which occur south of the river but not north of it are common on the south bank, a few miles from favorable but uninhabited territory on the north.

Seemingly the pre-Vashon faunas of western Oregon and Washington were similar. Some species became extinct in Washington in the course of Vashon isolation. Others persisted. The very close relationship of the mammals of the first group indicates some crossing of the river. The best known of such crossings was that of the Beechey ground squirrel which, previous to 1915, was unknown in Washington. In 1915, when there was no man-made bridge at White Salmon, it crossed the river and since has spread over an area of at least 50 square miles. The distribution of the mountain beavers is unusual in that the form in the lowlands of Washington is indistinguishable from the subspecies in the Cascades of Oregon.

The mammals that are racially distinct on the two sides of the Columbia River merit careful scrutiny. The Peromyscus of the two sides more closely resemble one another than those of southern Oregon resemble those of northern Oregon or than those of southern Washington resemble those of northern Washington. For Peromyscus maniculatus, the Columbia River is simply a convenient boundary for the separation of two slightly different races. The Oregon race of the bushy-tailed wood rat is a coastal type but the Washington form is the same as that of eastern Washington. Seemingly the more eastern race spread to an unoccupied habitat in western Washington. Other races that differ on the two sides of the Columbia probably developed while separated by the river.

Fig. 20. Rocky bluff along north bank of the Columbia River near Lyle. Washington. March 20. 1939. Habitat of Beechey ground squirrel and yellow-bellied marmot. (Fish and Wildlife Service photo by Victor B. [Scheffer]. No. 640.)

The San Juan Islands now possess a limited mammalian fauna. Unfortunately the activities of man have somewhat changed the native populations, especially by the introduction of the domestic rabbit which is now a serious pest in the islands. The Douglas squirrel, present on Blakeley Island, is said to have been introduced and one resident claims to have first brought it to the island. Two different persons claim credit for introducing the Townsend chipmunk on Orcas Island but do not account for its presence on Lopez Island. The three mammals most abundant and widely distributed in the islands are Sorex vagrans, Peromyscus maniculatus and Microtus townsendii. These species, at least, probably reached the islands at an early time. The two last named are now subspecifically distinct from their mainland relatives. Other mammals which probably were established before the arrival of the white man include the mink, otter, beaver, muskrat, raccoon and black-tailed deer.

The Great Basin Fauna of eastern Washington exists as three units, one on the Columbian Plateau, another in southeastern Washington and the third in the Yakima Valley area. The desert species of the Yakima Valley are more closely related to the species of eastern Oregon than they are to those of the Columbian Plateau. In a number of respects the Columbian Plateau gives indications of age. The ground squirrel, Citellus washingtoni, is related to, but specifically distinct from Citellus townsendii of the Yakima Valley and eastern Oregon. Perognathus parvus lordi is a well-marked race, as is Microtus pennsylvanicus kincaidi and Thomomys talpoides devexus. We suppose that these species were present on the Columbian Plateau at least through the Recent and probably through all of Wisconsin Time. The loess deposits of eastern Washington seem to have been laid down in Wisconsin and Recent times. These indicate an arid climate which, although probably cool, was probably not so cold as to exterminate these species. On the other hand, some species that are now abundant on the Columbian Plateau seem to have arrived there relatively recently. The black-tailed jack rabbit, for example, was unknown in eastern Washington before 1870 when it appeared in Walla Walla County. In 1905 it crossed the Snake River on ice and invaded the Columbian Plateau where it rapidly spread over the whole area. In January, 1920, it crossed the Columbia in two places and spread over the Yakima Valley.

The known facts of this movement were sufficiently impressive to cause the author to study rather closely the distribution of mammals in this area. The collection of bones from a cave along the Columbia River near Vantage, Grant County, on the Columbian Plateau, is especially helpful in this respect. This cave was first visited in 1938. It had been the habitat of owls, bats, and primitive man. The floor of the cave was buried under from one to three feet of bat guano, much of which had been hauled away for fertilizer. Here and there we found traces of fire and occasional piles of mussel shells. Some arrowheads and one beautiful obsidian spear head were found, all buried in guano and about midway between the floor and the top of the deposit. Remains of mammals were abundant through the bat guano, and apparently had been brought to the cave both by man and owls. The jaw of a mountain sheep was found. This species was known to be present when the first settlers reached the area ([Cowan], 1940: 558). The remains of smaller mammals included gopher, pocket mouse, muskrat, meadow mouse, deer mouse, coyote and white-tailed jack rabbit. No remains of cottontail, black-tailed jack rabbit or harvest mouse were found. The absence of the cottontail was especially surprising, in that fully thirty skulls of white-tailed jack rabbits were noted. The grasshopper mouse (Onychomys) was also absent, but this species is not common. The two rabbits and the harvest mouse, however, are abundant in the area today. The cottontail and harvest mouse have only recently been recorded from the Okanogan Valley of British Columbia ([Cowan] and Hatter, 1940: 9). The black-tailed jack rabbit has never been taken there.

Apparently then, some species have only recently entered the Upper Sonoran Life-zone of eastern Washington. They have, of course, reached the state from Oregon. The first step in the invasion probably was the occupation of southeastern Washington. No barrier prevents mammals from reaching southeastern Washington from eastern Oregon but the Columbia to the north and west prevents them from occupying the Yakima Valley, and the Snake River prevents them from reaching the Columbian Plateau. The kangaroo rat, Great Basin striped skunk and Great Basin spotted skunk now are at this stage of invasion. The second stage was the crossing of the Columbia River to the Yakima Valley. This has been accomplished by the black-tailed jack rabbit and, earlier, by the pocket mouse, Perognathus parvus parvus, and ground squirrel, Citellus townsendii. The third stage was the crossing of the Snake River and occupation of the Columbian Plateau. The final stage is the crossing of the northern Columbia River and occupation of the Okanogan Valley.

SPECULATION AS TO THE LATER DISTRIBUTIONAL
HISTORY OF THE MAMMALS

Whereas it is probable that a few of the species now occurring in Washington evolved there, most are immigrants from other areas. The success of a given species in any area is dependent on numerous factors which may be classified under food, shelter from the elements, protection from enemies and safe breeding places. The factors may be of an inorganic nature, such as climate, soil and exposure or they may be organic, such as vegetation, competition for food and response to enemies. Abundance results in population pressure and a tendency for the range of a species to expand.

Mammalian populations are dynamic and change in accordance with alterations in environment. Because the later geologic history of the state of Washington was violent, with resultant changes in climate and geography, the mammalian populations and the distribution of the species have changed much. With changes in environment, rare species may become common; common and widespread species may become rare or extinct; species foreign to the area may enter, become established and affect the distribution of other forms.

Subspecies are groups of individuals with similar genetic components or are groups of microgeographic races. In instances where the phenotypic expression of these similar genetic factors, or the "characters," are, as a unit, uniformly different from those of animals of the same species in another geographic area, it is convenient to give recognition to the two kinds by separate subspecific name. Intergradation between two geographically adjacent subspecies occurs, directly or where impassable barriers separate them, indirectly by way of one or more other subspecies. Subspecies of mammals are geographic races, which means that to warrant recognition by subspecific name, there must be a logical geographic range in addition to morphological characters.

Timofeef-Ressovsky (1932, 1940) advances the theory of harmoniously stabilized gene-complexes to account for the persistence of subspecies. The persistence of subspecies as genetic units has been best explained, I feel, by [Sumner] (1932: 84-86) who theorizes as follows:

1. The number of young produced by a subspecies is greater than the carrying capacity of the land they occupy, at least at certain times or in some years.

2. Population pressure results, with a tendency of individuals to emigrate outwards, to the border of the range of the subspecies, where the population pressure is less.

3. The outward moving tendency keeps the center of the range of the subspecies genetically "pure."

4. The peripheral wave continues, as long as favorable habitat is encountered, until an oppositely directed wave of another race is encountered.

5. Areas of intergradation represent local mingling of genetic factors and do not affect the "pure" individuals of the central part of the range of the subspecies.

Certain aspects of this hypothesis are strongly supported by the distribution of mammals in Washington. Witness the rapid invasion of Citellus beecheyi and Lepus californicus in Washington, and the eastern cottontail in western Washington and the domestic rabbit in the San Juan Islands. The volume of the "wave of population pressure" where no opposing force is met, is scarcely believable. In seven years the eastern cottontails released in southwestern Washington multiplied from a maximum of 12 individuals to a minimum of 40,000.

Competition between subspecies where their ranges come into contact seems to be exceptional. Peromyscus maniculatus oreas and P. m. austerus seem to afford an example of this. However, in a few cases subspecies seem to be determined in part by adaptation to restricted environments; each race lives only where local conditions favor its respective adaptations.

In the pocket gophers, where restricted habitat and fossorial habits cause numerous microgeographic races, these microgeographic races may be potential subspecies. This is especially true in the Puget Sound area, where six races occur in a small area. These races meet all the requirements of subspecies and are recognized as such. It should be pointed out, however, that these races and probably many other races produced by isolation, may represent degenerative mutations of the type mentioned by [Wright] (in [Huxley], 1940). The principal differences of such races seem to have resulted from the loss of factors of original multiple factor series, with resultant homogeneity of the race. Inherent variability is another thing that has to be taken into account when considering the differentiation of the mammals of Washington into subspecies. The pocket gopher is an extremely plastic species, especially in Washington, whereas the Douglas squirrel is less so. The flying squirrels, the yellow-pine chipmunk and the snowshoe rabbit are the other plastic species. These species are not so likely to break up into numerous subspecies over all of their ranges as they are in Washington where in a small area the topography is highly varied. The range of the one subspecies, Tamias amoenus amoenus, to the southeast of Washington is larger than the combined ranges of all six races occurring in Washington but, so far as I can see, the topography and environment are no more varied in Washington than in the mentioned area to the southeast of it. The range of one subspecies, Lepus americanus americanus, in Canada is several times larger than the entire state of Washington, in which four races are found.

The shrews are poor subjects for a study of differentiation, principally because their small size makes it difficult to see morphological variations that may be present. The difficulty is increased because cranial sutures become ossified at an early age. Although it is difficult to evaluate the differentiation in them, there is some. The bats, especially the Myotis, are less restricted by geographic barriers than are terrestial mammals. Nevertheless, obvious differentiation exists. The larger predatory mammals and the artiodactyls are able to move over large areas, at least in the breeding season, but in these animals also, some differentiation has occurred.

The greatest changes, other than the extinctions, to occur in the mammalian fauna of Washington since the late Pleistocene, are changes in distribution. The interglacial cycle preceding the Vashon-Wisconsin glaciation was of far greater duration than the Recent. Presumably the mammalian fauna had, from a distributional standpoint, reached a relatively stable condition. The descent of the Vashon-Wisconsin ice destroyed the stability and set parts of the fauna in motion. Probably no stability was reached before the ice began to recede, and when it did so the previous movements of the various species were, at least in part, reversed. Stability has not yet been reached by the mammalian fauna of Washington. Great changes have occurred in historic times and other changes probably are under way at present.

In the following pages an attempt has been made to interpret the probable late Pleistocene and Recent distributional history of the species of mammals occurring in Washington. The interpretations are made in the light of what is known of the physical history of the state and are to be accepted as such rather than as evidence for the conclusions made concerning the physical history of the state of Washington and adjacent areas.

Scapanus townsendii.—Probably this animal was confined to the Humid Transition Life-zone of the Pacific Coast since the Pliocene.

Scapanus orarius.—This species probably had a history similar to that of townsendii up to the late Pleistocene. It seems slightly more adaptable than townsendii, and to be able to extend higher into the mountains. The distribution of the subspecies orarius is almost exactly that of S. townsendii. In Oregon, orarius extended eastward over the Cascades where the subspecies schefferi developed. Perhaps this subspecies developed since the Pleistocene and since that time extended along the Columbia River Valley to southeastern Washington. The race yakimensis, in the Yakima Valley area, is closely related to schefferi, and seemingly could have been developed from a stock of schefferi that migrated westward across the Simcoe Bridge.

Neurotrichus gibbsii.—The history of Neurotrichus in North America was probably similar to that of the two species of Scapanus. It tolerates environmental differences to about the same degree that Scapanus orarius does but occurs much farther south (Monterey County, California) than S. orarius. This may be because Neurotrichus has no counterpart to compete with it in the south, whereas Scapanus orarius must compete in northern California with the morphologically similar Scapanus latimanus. S. orarius stops short at this place and S. latimanus occupies all the territory to the south.

The shrew-mole of the lowland of Washington (N. g. minor) probably became distinct from the mountain subspecies (gibbsii) in Vashon-Wisconsin time.

Sorex cinereus.—It is reasonable to suppose that the cinereous shrew had a continuous range across the forested area of British Columbia in pre-Wisconsin time. Without having been isolated, the dark coastal race (streatori) may have developed from the wider-ranging inland cinereus, as a response to the denser, humid, coastal forest-habitat, after having been forced southward to Washington by the Vashon Glaciation. Since that time it is presumed to have reoccupied the coast of British Columbia and southern Alaska. This coastal race might have developed in Vashon time, while isolated in southwestern Washington. The Cascades are populated by a race of the Rocky Mountain Fauna, S. c. cinereus, which probably entered the Cascades from northeastern Washington or British Columbia in Recent Time. The absence of the species in western Oregon, its rarity in western Washington, and its abundance farther north suggest a northern origin and northward rather than southward postglacial movement. Had the full species cinereus been a preglacial resident of western Washington we would expect streatori or a race related to it to occur in the Cascades.

Sorex merriami.—The periphery of the range of this member of the Great Basin Fauna may have been in southeastern Washington since pre-Wisconsin time.

Sorex trowbridgii.—This shrew is a typical Pacific coastal species with an extensive range along the Pacific Coast south of Washington. The Washington population may have been isolated in southwestern Washington during Vashon time or may have crossed the Columbia into Washington from western Oregon early in the Recent. Since the retreat of the ice it has extended northward to southern British Columbia and eastward to the eastern side of the Cascades. Save for crossing the Cascades its postglacial movements have been slight, as is typical of Pacific Coastal species. The race destructioni probably has been isolated on Destruction Island for several thousand years.

Sorex vagrans.—This species probably has had a continuous range over the western United States since the late Pleistocene. The dark coastal race (vagrans) probably was differentiated from the paler races of the Great Basin in response to the more humid climate along the coast.

Sorex obscurus.—The history of this shrew of alpine predilection probably corresponded closely to that of Sorex cinereus. The derivation of the dark, long-tailed, coastal race (S. o. setosus) from the smaller, paler, inland race (obscurus) probably occurred before Vashon-Wisconsin Time. Sorex o. setosus is one of a complex of races distributed along the Pacific Coast from Alaska to California.

Sorex palustris.—This species has a wide range in North America and extends southward in the Cascade-Sierra Nevada Chain to southern California. Its extensive range at present in this mountain chain suggests that it was resident in the Cascades previous to Wisconsin time. Mountain water shrews probably reached the Olympic Mountains from the Cascades by way of the Puget Bridge in early Recent Time.

Sorex bendirii.—This Pacific Coastal species probably had a history very similar to that of Neurotrichus and Scapanus orarius.

The difference between the Bendire water shrews of western Washington and western Oregon indicates that the Washington population was separated from the shrews of western Oregon during Vashon Time. The white-bellied race of the Olympic Peninsula is probably of local origin.

Microsorex hoyi.—The Washington record of this shrew at Loon Lake, Stevens County, is in an area where mammals typical of the Rocky Mountain Fauna occur.

Myotis lucifugus.—The dark race of this species (alascensis) may have persisted through the glacial period in southwestern Washington. The race carissima, of the Great Basin Fauna, may have entered the state since the glacial period, from the south, of course. Habitat selection determines their range at present.

Myotis yumanensis.—The dark, coastal race (saturatus) seems to be an established member of the Pacific Coastal Fauna. Unlike lucifugus, the coastal race is not found east of the Cascades. The race sociabilis, of the Great Basin, has doubtless entered the desert of eastern Washington from eastern Oregon.

Myotis keenii.—The southernmost record station for this north coastal species is on the Olympic Peninsula of Washington. It probably developed in the humid, northern part of the Pacific Coastal area previous to the last Pleistocene glaciation and extended its range to the south in Vashon-Wisconsin Time. The range of tolerance in M. k. keenii seems to be more restricted than that of M. lucifugus alascensis.

Myotis evotis.—In Washington, the distribution of this bat is similar to that of Myotis lucifugus. The dark, forest race probably originated in the north-coastal region. The paler race, that developed in the southwest, entered eastern Washington from Oregon.

Myotis thysanodes.—In Washington this species has been recorded only in the southeastern part where the Great Basin Fauna occurs. It probably originated in the southwestern United States, and a point in British Columbia a little way north of Washington marks the northern edge of its natural range.

Myotis volans and Myotis californicus.—Remarks made about Myotis lucifugus apply also to these two species.

Myotis subulatus.—The northwestern periphery of the range of this species seems to be in eastern Washington.

Lasionycteris noctivagans.—Undifferentiated subspecifically from coast to coast, no basis is provided for judging the route by which this species entered the state.

Pipistrellus hesperus.—The northwestern periphery of the range of this bat, also, lies in eastern Washington.

Eptesicus fuscus.—Big brown bats from both eastern and western Washington seem to have been derived from the Pacific Coastal race of the species. Presumably it extended its range westward across the Cascades in early post-Pleistocene Time.

Lasiurus cinereus.—No speculation as to the distributional history of the hoary bat seems justified at present.

Corynorhinus rafinesquii.—The dark, coastal race of this bat probably persisted in southwestern Washington and western Oregon through Vashon Time and moved northward in the Recent. The paler intermedius probably invaded eastern Washington from eastern Oregon in the Recent.

Antrozous pallidus.—This species strays into eastern Washington from Oregon as part of the Great Basin Fauna.

Ursus americanus.—The dark, western race of the black bear (altifrontalis) and the paler, inland race (cinnamomum) were probably separated by a glacial divergence. The inland race has entered northeastern Washington in the Recent with other members of the Rocky Mountain Fauna.

Ursus chelan, etc.—The apparent past distribution of chelan indicates it to have invaded Washington from British Columbia since the Pleistocene.

The apparent absence of grizzly bears from the southern Cascades and western Washington may indicate their absence from these areas immediately before pre-Vashon time, or their extermination in or shortly after that period.

Procyon lotor.—The raccoon of western Washington seems to be the Pacific Coastal race which occurs also in western Oregon and northwestern California. This indicates that the coastal race (psora) was confined to the coastal area south of Washington during Vashon Time and has only recently reinvaded western Washington. It is possible, though less likely, that raccoons existed in southwestern Washington during Vashon Time but did not develop racial characters, or that the Columbia was crossed so frequently that genetic differences were dispersed throughout the entire population.

Reasons why the second hypothesis is inadequate are: (1) Raccoons range but little north of the state of Washington, both east and west of the Cascades. (2) Raccoons of western Washington and the area about San Francisco Bay, California, are as much alike as are raccoons from southwestern Washington and northwestern Oregon. It is thought that raccoons, if resident in western Washington since interglacial time, would have developed strong racial characters, and the fact that they have not indicates that they have entered the state at a relatively recent date.

The raccoon of eastern Washington (excelsus) is a member of the Great Basin Fauna and has probably included southeastern Washington in its natural range for a long period of time. The raccoon has not extended its normal range into northeastern Washington, although it is seemingly ideal raccoon habitat; only an occasional vagrant occurs there. A stock of raccoons from which emigrants might come has existed in southeastern Washington and the Yakima Valley for some time. The Columbia River might serve as a highway by which emigrants could reach northeastern Washington.

Martes caurina.—The earlier distributional history of the western marten has been postulated by [Davis] (1939: 131-132), who stated: "When the ancestral stock split into the two groups, the one that gave rise to americana may have pushed eastward across Canada to the Atlantic Coast; the other, giving rise to caurina, may have migrated southward along the Sierra Nevada-Cascade and Rocky mountains. Perhaps the great ice sheet was instrumental in pushing americana eastward and separating it geographically from caurina." The present occurrence of americana in Alaska and British Columbia is thought to have been by invasion from the east in postglacial time.

[Davis]' theory seems basically correct but subject to correction in detail. The presence of caurina in the southern Rocky Mountains suggests that it is not a Pacific Coastal species in the common sense. Had americana occupied northern British Columbia in pre-Wisconsin Time, it and not caurina would be expected to occur in the southern Rocky Mountains today, for the form found in British Columbia almost certainly would have been forced into the Rockies. The range now occupied by caurina in the Rocky Mountains is so extensive as to suggest that martens could not have migrated into all of it from the Pacific Coast since Vashon Time, even had the region been unoccupied by any species of marten. The presence of americana in Alaska and British Columbia suggests that it arrived in those areas before caurina and that had the Rocky Mountains been unoccupied by martens in pre-Wisconsin time, americana and not caurina would have reached the Rockies first. It appears that caurina occupied much of western North America in pre-Wisconsin Time and was forced southward into the southern Rocky Mountains and along the Pacific Coast by Vashon-Wisconsin ice.

The separation of americana and caurina may be supposed to have occurred before the pre-Vashon-Wisconsin interglacial interval, perhaps by a glacier similar to but antedating the Vashon-Wisconsin glaciation.

The martens of western Washington (Martes caurina caurina) are a coastal race. Those of northeastern Washington belong to a race of the Rocky Mountain Fauna, and are referred to M. c. origenes. [Davis] (1939: 132) refers the martens of Idaho to Martes caurina caurina. I have compared specimens from Idaho with animals trapped for fur from the Pacific Coast proper and feel that the animals from northeastern Washington and those from Idaho are more like origenes than caurina, although perhaps not typical. The animals from the Pacific Coast proper are caurina and have darker heads and brown instead of yellow patches on the throat.

Martes pennanti.—Fishers are found throughout the Cascade Mountains and probably were widely distributed over western North America in pre-Wisconsin Time.

Mustela erminea.—The distribution of ermines along the coast of northern California and in the Cascade-Sierra Nevada of Oregon and California indicates, as does their differentiation there, that they ranged southward to these areas before and during Vashon-Wisconsin Time.

In immediate pre-Vashon-Wisconsin Time, the dark race streatori probably occurred in western Washington. The race murica probably occurred in the Blue Mountains then, as it does today, but probably occurred also in the Cascades of Washington. The descent of the Vashon glaciers probably displaced streatori from the northern part of its range, at least temporarily. In the Cascades, murica was likewise forced southward. Ermines related to the northern richardsonii were forced into northern Washington and Idaho by the Wisconsin ice. They probably were unable to live on the barren, unglaciated plains of eastern Washington but persisted in Idaho.

The ranges of the three forms at the maximum extent of the Vashon-Wisconsin may be reconstructed as follows: streatori in southwestern Washington; murica in the southern Cascades and the Blue Mountains; invicta stock in northern Idaho. While so isolated, the ermines of the southern Cascades probably mingled, to a certain extent, with streatori and developed the characters that now separate gulosa from both murica and streatori. The intermediate nature of gulosa has been mentioned by [Hall] (1945: 85).

The retreat of the ice allowed streatori to move north and invicta to move north and east into Washington and the northeastern Cascades. To a lesser extent, gulosa may have moved north. The poorly-marked race olympica probably evolved from streatori in the Recent. It is difficult to account for the dark race fallenda.

It must have evolved from streatori in the Recent but the origin of such a strongly marked race in such a short time is surprising. It might be mentioned that a similarly differentiated race of chipmunk, Eutamias amoenus felix, occupies much the same range.

Mustela frenata.—The long-tailed weasels of the Pacific Coast behave as a plastic group and clearly show the effect of the Vashon-Wisconsin Divergence. The range of the coastal race, altifrontalis, indicates that it was isolated in southwestern Washington during Vashon Time. In that period, or shortly after, it extended its range southward but only along the extreme, coastal area of Oregon (see [Hall], 1936: 101). Following the retreat of the ice it extended its range northward to the deglaciated area of western Washington.

Also following the retreat of the ice, a Great Basin subspecies (nevadensis) extended its range northward. This race seems to have been more adaptable and successful than other kinds of Great Basin mammals, for it extended its range farther northward, eastward and westward than most.

A third race, washingtoni, was isolated in the southern Cascade Mountains during Vashon Time and became differentiated from both altifrontalis and nevadensis. It is now found in the Cascades from central Oregon north to Mount Rainier. It is difficult to see why it did not extend its range to include the northern Cascades when the glacial ice left, but it did not. Instead altifrontalis entered the northern Cascades from the west and nevadensis did the same from the east. Weasels obtained in habitats north of Mt. Rainier are intergrades between altifrontalis and nevadensis.

One is reminded here of the douglasii group of Thomomys talpoides in which subspecies did not move north of Mt. Rainier in postglacial time. The area north of Mt. Rainier was populated instead by gophers of the fuscus group, subspecies of which invaded the area from the east. Perhaps Mt. Rainier itself served as a barrier to alpine mammals in the immediate post-Pleistocene. Perhaps Mustela f. washingtoni will eventually extend its range northward, displacing the altifrontalis-nevadensis intergrades from the habitats to which washingtoni may be better adapted.

The Blue Mountains of southeastern Washington are occupied by a weasel (effera) that has a more extensive range in eastern Oregon. The range of this race has probably not changed materially for a long period of time.

One would expect the weasels from extreme northeastern Washington to be referable to the race oribasa, of the Rocky Mountain Fauna. Instead they are intermediate between that race and the Great Basin race, nevadensis. Apparently nevadensis was so dynamic and adaptable that it actually entered the geographic ranges of surrounding races for some distance. In view of [Sumner]'s theory for the retention of subspecies, one might say that the population pressure of nevadensis on the periphery of its range is stronger than the opposing pressure of some surrounding races.

Mustela vison.—Pending a review of the minks of North America, little can be said concerning their historical distribution in the state of Washington. From the general range of the species in western North America, one would expect some effect of the Vashon-Wisconsin Divergence to be apparent. There is some evidence for this. Minks from Idaho and adjacent parts of British Columbia are distinctly less reddish than minks from the area about Puget Sound, as noted by [Davis] (1939: 138).

Gulo luscus.—The range of the subspecies luteus, peculiar to the Cascades and Sierra Nevada suggest that the wolverine may have been forced southward in the Cascades and there isolated during Vashon Time. The differences separating the southern race from the northern may have been developed while the two populations were isolated. The range of the wolverine was probably more extensive in glacial and immediate postglacial time than at present.

Lutra canadensis.—The otter of western Washington seems to be a member of the Pacific Coastal Fauna. Little can be said regarding the distributional history of the species in the state, for specimens from eastern Washington are not numerous enough to permit of a person certainly establishing their systematic position.

Spilogale gracilis.—The western race of the civet cat (latifrons) seems to be a coastal race, isolated in southwestern Washington and western Oregon during Vashon time. The eastern race, saxatilis, is a race of the Great Basin Fauna, that has entered the state from Oregon and that will probably extend its range to the north.

Mephitis mephitis.—Of the four subspecies of skunks occurring in Washington, two seem to have been resident in the state during Vashon Time. The western race, spissigrada, was probably isolated in southwestern Washington and extended its range northward, in the deglaciated area of western Washington, after the retreat of the ice. Another race (notata) was probably isolated in the southeastern Cascades and adjacent Oregon. M. m. hudsonica of the Rocky Mountain Fauna entered the northeastern part of Washington after the ice retreated from there. A race of the Great Basin Fauna, major, entered southeastern Washington from Oregon and may eventually extend its range farther north.

It is interesting to note that both of the western races, spissigrada and notata, both of which probably developed in Washington during Vashon Time, occupy limited ranges in adjacent Oregon ([Bailey], 1936: 308).

Taxidea taxus.—This species has probably long been resident on the Columbian Plateau and in southeastern Washington. For the early distributional history of the species see [Hall] (1944: 17). Pleistocene remains, referable to this race, have been found in Franklin County.

Vulpes fulva.—The red fox of the Cascades was probably isolated there during Vashon Time by glacial ice. Its range extends southward in the Cascades to Oregon. The fox of eastern Washington is probably a member of the Rocky Mountain Fauna that lived in the Blue Mountains of southeastern Washington in Wisconsin Time and that emigrated to northeastern Washington in Recent Time.

Canis latrans.—The distributional history of the coyote in Washington is not clear.

Canis lupus.—The dark wolf (fuscus) of western Washington is probably a coastal race. The race that may have occurred in northeastern Washington probably was an invader from the Rocky Mountain Fauna, and the race that possibly occurred in southeastern Washington would be assumed to have long been a resident of the area.

Felis concolor.—The cougar of western Washington is a coastal race, probably developed while isolated in southwestern Washington and western Oregon. The cougar of northeastern Washington probably entered the state with other Rocky Mountain species, early in the Recent. The cougar of the Blue Mountains of southeastern Washington has probably long been resident there.

Lynx rufus.—The bobcat of western Washington seems to be a coastal race that was isolated in either southwestern Washington or western Oregon by Vashon ice. It has since extended its range into southern British Columbia. The bobcat of eastern Washington seems to be a member of the Great Basin Fauna that has spread to some forested areas on the periphery of the more arid life-zones.

Lynx canadensis.—The lynx is an element of a northern fauna that was probably forced southward into the Cascades and Rocky Mountains. Its range was probably more extensive, as is indicated by the scattered records of its occurrence in Oregon ([Bailey], 1936:271).

Marmota monax.—The woodchuck invaded northeastern Washington in the early Recent with the Rocky Mountain Fauna.

Marmota flaviventris.—The yellow-bellied marmot is a typical member of the faunas of the Great Basin and the southern Rocky Mountains. It has doubtless entered southeastern Washington from eastern Oregon at an early time. In northeastern Washington, west of the Columbia River, it occupies alpine habitat, but it does not occur farther east, where Marmota monax is found, or in the Cascades where Marmota caligata lives.

The yellow-bellied marmots are great wanderers, and commonly are found in scattered outcrops far out on the Columbian Plateau. There is even one record for western Washington, near Bellingham, Whatcom County. This individual must have crossed some low pass in the Cascades from the area about Lake Chelan. There are records of eastern Washington birds occurring in this same area, so it seems likely that the marmot was a natural stray and not an animal that escaped from captivity.

Marmota caligata.—The absence of the hoary marmot from the Cascades of Oregon, and the presence there of Marmota flaviventris, indicates that the species did not occur in the southern Cascades of Washington during Vashon Time. Presumably the hoary marmot is a member of the fauna of the northern Rocky Mountains and entered the Cascades of Washington in the Recent, after which it spread widely and rapidly owing to lack of competition with any established species of marmot.

Marmota olympus.—This species has probably lived in the Olympic Mountains since pre-Vashon Time.

Citellus washingtoni.—This ground squirrel has probably lived on the Columbian Plateau since before Wisconsin Time.

Citellus townsendii.—The Townsend ground squirrel probably entered the Yakima Valley area from Oregon. The differences between it and its relatives in Oregon indicate a considerable period of isolation but one far shorter than the period during which washingtoni is presumed to have been isolated from townsendii.

Citellus columbianus.—The Columbian ground squirrel might have been forced southward in the Rocky Mountain area by the Wisconsin glaciation, might have lived in southeastern Washington since then, and might have invaded northeastern Washington in the Recent with other species of the Rocky Mountain Fauna.

Citellus beecheyi.—This ground squirrel is known to have entered Washington about 1915 from Oregon.

Citellus saturatus.—The mantled ground squirrel of the Cascades probably evolved, from the lateralis stock, as a separate species while isolated in the southern Cascades during Vashon Time. It is a poorly differentiated species and may actually be instead a strongly marked subspecies.

Citellus lateralis.—The golden-mantled ground squirrels of northeastern and southeastern Washington are closely similar. It is deduced that connectens of southeastern Washington developed the differences that characterize it while isolated, from the main stock, in the Blue Mountains area of Washington and Oregon.

The race found in extreme northeastern Washington (tescorum) probably reached that area in relatively recent times. Its range in Washington is more restricted than that of several other members of the Rocky Mountain Fauna; areas of suitable habitat west of the Columbia River are not inhabited by these ground squirrels. Its range in Washington is almost exactly that of (Marmota monax).

Tamias minimus.—The least chipmunk of the Yakima Valley is the same race (scrutator) as that occupying the Great Basin area of Oregon and Nevada. It must have crossed the Columbia in relatively recent times. Had it been resident in the isolated Yakima Valley area for any considerable period of time, the development of distinctive racial characters there would be expected. Perhaps, then, it has not been resident there as long as has the Townsend ground squirrel which, though closely related to the ground squirrel of eastern Oregon, is racially distinct.

The least chipmunk of the Columbian Plateau is thought to be racially distinct from its relatives in the Yakima Valley and eastern Oregon. Probably it reached the Plateau very early in the Recent. It has probably not been separated from the parent stock as long as has the ground squirrel (Citellus washingtoni) of the plateau. The ground squirrel is specifically rather than racially distinct.

Tamias amoenus.—The distributional picture of the yellow pine chipmunks in Washington is complex. (Fig. 81.) Certain habits of these mammals doubtless have modified what was probably the original postglacial distribution of the species. Chipmunks are diurnal and natural selective factors for color possibly operate more strongly on animals active by day than on nocturnal animals. Yellow pine chipmunks are neither forest nor desert inhabitants. Indeed, dense forests or open deserts serve as barriers to their distribution. They prefer brush lands, open woods, and other habitats where there is food and cover but abundant sunlight. In such habitats they are almost independent of altitude, temperature and humidity. They live in the Olympic Mountains where rainfall is heavy and humidity high. They live and breed at considerable altitudes in the Cascades, even in the crater of Mount Rainier, where snow, ice and freezing conditions exist the year around. On the other extreme, they occupy the low, open pine forests and brush lands at the lower edge of the Arid Transition Life-zone where temperatures, in summer, are high and rainfall scarce.

We find in the present distribution of the species in the Cascade-Sierra Nevada chain and the Rocky Mountains, indication that the species had a wide geographic range over western North America previous to the Vashon-Wisconsin glacial interval. Probably the range of the species extended in an arc, from the Rocky Mountains across northern Washington to the Cascades, around the basaltic plateau desert in eastern Washington and Oregon. Presumably the descent of the Vashon-Wisconsin glaciers broke this arc into two parallel geographic ranges, the Rocky Mountains and the Cascade-Sierra Nevada chain, with a desert area between.

Almost every species of forest-dwelling animal had its range separated into two parts by the southward movement of the glaciers. Most of these forest-dwelling species were composed of relatively homogeneous stocks, although the yellow pine chipmunk probably was not. The extensive range of tolerance of the yellow pine chipmunk to altitude and climate and its unique habitat requirements cause it to meet radically different natural selective factors. The predators of the chipmunks near Wenatchee, Chelan County, would include: rattlesnake, gopher snake, badger, striped skunk, prairie falcon, red-tailed hawk and other predominantly desert-dwelling species. The chipmunks at Stevens Pass, in the mountains to the west, would have to contend with: marten, black bear, goshawk, bald eagle and other alpine predators. At the present time, the chipmunk of the eastern Cascades is racially distinct from that of the higher Cascades. Geologic and botanical evidence indicates that the Columbian Plateau was a desert in pre-Wisconsin Time. We suppose that a transition from alpine conditions in the Cascades to desert conditions on the Columbian Plateau existed even in pre-Wisconsin Times. We suppose also that the chipmunk existed in this transition area and in the Cascades before Wisconsin Time and in the southern and southeastern Cascades during Wisconsin Time. We further suppose that the differences separating the transition area race (Tamias amoenus affinis) from the mountain race (T. a. ludibundus) came about through natural selection and not as a result of geographic isolation. The principal difference between the two is the paler color of the race in the transition area.

The descent of the Vashon-Wisconsin glaciers, then, found two races of the yellow pine chipmunk in the Cascades. Chipmunks living north of the Columbian Plateau, in northern Washington and British Columbia, were probably forced southward onto the inhospitable plains of the plateau and exterminated. Farther east, north of northeastern Washington, chipmunks from the north were probably forced southward to compete with resident chipmunks.

The range of Tamias amoenus luteiventris in Washington, Idaho and Montana is most unusual (See [Howell], 1929; [Davis], 1939). From a compact range in Montana, two long fingers reach northward and westward. The western finger crosses Idaho to end in the Blue Mountains of Oregon and Washington. The northern finger crosses northern Idaho, northeastern Washington and extends on into southern British Columbia. Between these two fingers of the range of luteiventris another race (canicaudus) is found. This race occupies a more lowland area than does luteiventris. The range of luteiventris in the northern Rocky Mountains is extensive. Presumably this race occupied an area farther north in pre-Wisconsin Time and was forced southward to its present range by the Wisconsin glaciers. The original population occupying extreme eastern Washington and adjacent Idaho was Tamias amoenus canicaudus. The pre-Wisconsin range of this race might have been more extensive. At any rate, luteiventris which was driven southward displaced canicaudus, or some other race of chipmunk, from much of the Rocky Mountains south of the glacier. The northern chipmunks were adapted to more boreal conditions and perhaps otherwise better suited to environmental conditions of the northern Rocky Mountains. A small population of the older established race (canicaudus) persisted in lowland areas of eastern Washington and adjacent Idaho.

Regarding the range of canicaudus, surrounded by the range of luteiventris on three sides and faced by desert on the west, [Davis] (1939: 220) writes, "It may be that, of these two races, luteiventris has a greater range of tolerance to environmental conditions and, thus, is able to succeed in areas to which canicaudus is not adapted. This inference is supported by the fact that luteiventris occupies a large range which is diversified geographically and climatically, whereas canicaudus seems to be limited to a much smaller, more nearly uniform area." Seemingly canicaudus now exists only in an area ideally suited to it, and one where it can successfully compete with the generally more adaptable and successful luteiventris. The maximum extent of the glacial ice, then, found luteiventris the dominant chipmunk in the northern Rocky Mountains, with an isolated population of canicaudus in eastern Washington and adjacent Idaho.

The topography of the ground moraine exposed by the retreat of the Vashon-Wisconsin glaciers was a barrier to many species of mammals. The rough, rocky surface with thin soil probably first supported mosses and grasses, then brush, and later trees. The earlier stages of plant succession on the deglaciated ground probably presented ideal habitat for yellow pine chipmunks. Certainly the races immediately adjacent to the glaciers extended their ranges farther north than many species. In eastern Washington, T. a. luteiventris spread to the northeastern corner of the state and on into British Columbia. In the northern Cascades, T. a. affinis spread northward and eastward, across the Okanogan River, into northeastern Washington as far as the range of luteiventris. The chipmunk of the higher Cascades (ludibundus) likewise extended its range northward into British Columbia. In the northwestern Cascades of northern Washington and southern British Columbia, a richly-colored race, T. a. felix, now occupies a limited geographic range. This race doubtless originated from ludibundus stock but the method of its development is unknown. Perhaps in early postglacial time, selective factors developed in chipmunks of the western slopes of the Cascade Mountains the rich, dark color of felix. The ancestral ludibundus may have given rise to a pale race, affinis, in the arid eastern Cascades and a dark race, felix, on the humid western slope of the Cascades. This seems improbable for there is no trend to darker color on the western border of the range of ludibundus south of the range of felix, and instead, affinis may have given rise to ludibundus. A more appealing hypothesis is that a local mutation in some ludibundus stock so changed the range of tolerance of a portion of the population that it was allowed to enter the more dense habitat along the coast north of the Fraser River and, there, isolated by habitat selection, it developed the characters of felix. Population pressure later forced it eastward until the eastern border of its range again met the range of the ancestral race, ludibundus.

The chipmunks of the Olympic Mountains probably reached their present range from the Cascades. Their probable path of emigration was westward from Mt. Rainier, along the glacial outwash train of Nisqualli Glacier, to the moraine and outwash apron of the Vashon Glacier and thence to the Olympics. So similar are the chipmunks of Mt. Rainier and the Olympic Mountains that [Howell] (1929) included Mt. Rainier in the range of caurinus.

Briefly summarized, the probable pre-Vashon-Wisconsin distribution of chipmunks of the species Tamias amoenus in Washington was: ludibundus in the higher Cascades; affinis in the eastern Cascades; canicaudus in eastern Washington and adjacent Idaho; and luteiventris in the area north of the range of canicaudus. The descent of the Vashon-Wisconsin ice restricted but did not materially alter the ranges of ludibundus or affinis. On the east, luteiventris was forced southward to compete with canicaudus and displaced it over a large region, especially in mountainous areas. Following the retreat of the ice, luteiventris, affinis, and ludibundus extended their ranges northward over the deglaciated territory. A stock of ludibundus that moved westward from Mt. Rainier became isolated and gave rise to caurinus. In some less obvious development, ludibundus stock gave rise to felix north of the Fraser River in the Cascades.

Tamias ruficaudus.—Until a better understanding of the range of this chipmunk and its relation to other Tamias is gained, uncertainty will remain concerning its distribution in the past.

Tamias townsendii.—This is a typical coastal species that ranges southward, along the coast, to California. The lowland race of western Oregon and Washington (townsendii) probably occurred no farther north than southwestern Washington when the Vashon Glacier was in place. Chipmunks of this species in the Cascades and in the southern Olympic Mountains probably developed independently the slightly paler color that separates cooperi from townsendii. The tendency for species of the Pacific Coastal Fauna of the Cascades and the Olympic Mountains to be paler than their lowland relatives is widespread.

After the retreat of the ice, both races probably moved northward. Perhaps because of its alpine adaptations, cooperi has moved farther than townsendii. Also, townsendii, in the lowlands, ranges to the Fraser River, a barrier not encountered by cooperi.

Sciurus griseus.—This species of the Pacific Coastal Fauna probably entered Washington from Oregon since the retreat of the Vashon Glacier. It has probably entered the state in relatively recent times.

Tamiasciurus hudsonicus.—The two species of red squirrels, T. hudsonicus and T. douglasii, are specifically distinct and probably became differentiated in the Pleistocene when southward moving glaciers cut in two the range of the ancestral stock. The morphological differences are too great, comparatively, to have occurred during the Vashon-Wisconsin Divergence. T. hudsonicus probably occupied a range in pre-Wisconsin Time that included the Rocky Mountains and areas to the north. Glacial ice probably restricted the range of hudsonicus in Wisconsin Time but after the retreat of the ice hudsonicus moved northward to reoccupy its former range. It also moved westward across northern Washington to the Cascades, where it met the range of douglasii. Farther north, it moved westward to the Pacific, thus occupying an area that, in pre-Vashon time, probably was occupied by douglasii.

Tamiasciurus douglasii.—The Douglas squirrel probably occupied the coastal region of Oregon, Washington and British Columbia in pre-Vashon Time. The descent of the ice restricted its range to southwestern Washington and areas to the south. After the retreat of the ice it moved northward somewhat but, like other coastal species, the movement was slow. Meanwhile hudsonicus from the Rocky Mountain Fauna, had spread to the coast of British Columbia.

Glaucomys sabrinus.—This flying squirrel is a plastic species. It inhabits all of the forested parts of Washington. The distributional picture presented by the 5 races (Fig. 92) which occur in Washington is complicated. The ranges of 3 of these lie principally outside the state of Washington.

The race oregonensis occupies Washington and Oregon west of the Cascades; fuliginosus occupies the Cascades of Washington, Oregon and southern British Columbia; columbiensis occupies the interior valleys of British Columbia and adjoining Washington; latipes occupies the northern Rocky Mountains of British Columbia, northern Idaho and extreme northeastern Washington; and bangsi occupies the Blue Mountains of Washington and Oregon and a wide range in Idaho and eastward.

The differences separating the race oregonensis from other subspecies found in Washington are relatively great. This lowland race is smaller and richer in color. The other races exhibit slight but relatively constant differences. The relatively great difference between oregonensis and the other races indicates that oregonensis was isolated from the remainder of the species for a considerable time. Presumably oregonensis was a strongly differentiated coastal race in pre-Vashon Time and occupied most of western Washington and Oregon. The descent of the Vashon ice restricted the range of oregonensis to southwestern Washington and western Oregon. The descent of the ice forced a northern race, fuliginosus, southward into the range of oregonensis. The northern race, adapted to boreal conditions, was able to compete successfully with the established oregonensis only in mountainous areas. In the Cascade Mountains, fuliginosus extended its range southward to southern Oregon.

The descent of the Wisconsin ice in eastern Washington forced the flying squirrels of adjacent British Columbia southward into the Rocky Mountains. These squirrels were probably closely related to fuliginosus, or to bangsi, which latter race already may have been established farther south in the Rocky Mountains. The Blue Mountains of southeastern Washington were probably inhabited by bangsi in Wisconsin times, or even earlier. The retreat of the Vashon-Wisconsin glaciers allowed the flying squirrels to extend their ranges northward. In western Washington oregonensis moved to southern British Columbia. In the Cascade Mountains the more boreal fuliginosus moved much farther northward and, north of the Okanogan Valley, spread eastward to the arid, interior valleys of British Columbia. Subsequent differentiation in the population of the arid, interior valleys developed the slightly differentiated race columbiensis. Farther east, flying squirrels from the northern Rocky Mountains moved northward. Northeastern Washington and adjacent British Columbia were occupied by latipes, derived from bangsi.

Thomomys talpoides.—Views as to the probable historical distribution of this plastic group have been presented in an earlier report ([Dalquest] and [Scheffer], 1944: 308-333). This may be briefly summarized as follows.

Previous to Vashon-Wisconsin Times, pocket gophers occupied at least the Cascade Mountains and the Columbian Plateau of Washington. The race occupying the Columbian Plateau, devexus, was probably racially distinct in pre-Wisconsin time. The descent of the Vashon-Wisconsin glaciers isolated gophers in the southern Cascades. Three racial stocks developed there: shawi in the Mount Rainier area; limosus in the Columbia River Valley south of the Cascades; and immunis in the mountainous area between the other two races. At the maximum extent of the Wisconsin ice, gophers from the Columbia River Valley (limosus) were able to cross the Simcoe Bridge and reach the Blue Mountains. With the retreat of the Wisconsin ice, the Simcoe Bridge was closed. Gophers isolated in the Blue Mountains developed the racial characters of acqualidens and those between the Blue Mountains and the Columbia River intergraded with the desert race, devexus. These intergrades, which have, also, some characters of their own, bear the name columbianus. Gophers in the southern Cascades (limosus) moved westward on prairie-like river terraces to Clark County where, isolated, they became racially distinct (douglasii).

Gophers from the Mount Rainier area (shawi) moved westward on glacial outwash trains to the extensive outwash aprons of the Vashon glaciers in the area about Puget Sound. Here they multiplied and spread to the Olympic Mountains. Growth of forest on the original outwash apron broke the area into numerous isolated prairies. Gophers in the Olympic Mountains (melanops) were isolated from those in the area about Puget Sound. Six distinct races originated on the isolated prairie (glacialis, tacomensis, pugetensis, yelmensis, tumuli, couchi).

Following the retreat of the glacial ice from eastern Washington, pocket gophers from the Blue Mountains of Oregon (wallowa) moved northward into Washington and gophers from the Rocky Mountain Fauna of Idaho moved onto the deglaciated part of northeastern Washington. From northeastern Washington they spread westward to the Cascades and thence southward to meet the native gophers of the Cascades in the Yakima Valley Area. No racial differentiation in these gophers occurred; all are referable to fuscus. Where fuscus and the native gophers came together in the Yakima Valley, a new race, yakimensis, developed.

Perognathus parvus.—Three races of the pocket mouse occur in Washington. Two of these (lordi and columbianus) occur on the Columbian Plateau. Like many desert species that occur on the Columbian Plateau, the pocket mice are rather different than their relatives in eastern Oregon. Presumably they have been isolated on the plateau since before Vashon-Wisconsin Times.

The range of the pocket mouse of southeastern Washington, Perognathus parvus parvus, is continuous with the range of the race in Oregon. This same race occurs in the Yakima Valley, whence it probably arrived from Oregon in relatively recent time.

The distribution of pocket mice on the Columbian Plateau, in eastern Oregon and in the Yakima Valley resembles that of the least chipmunk in those areas. It is also similar to, but of more recent origin than, that of the ground squirrels, Citellus washingtoni, and townsendii.

Dipodomys ordii.—This kangaroo rat enters the desert area of southeastern Washington from Oregon. It may be expected eventually to cross the Columbia River to the Yakima Valley and the Snake River to the Columbian Plateau.

Castor canadensis.—Two races of beavers occur in Washington. One, found in southwestern Washington and northwestern Oregon, is dark with a short, wide skull. The other, ranging over most of the state, is paler with a longer, narrower skull.

The form now found in southwestern Washington and adjacent Oregon (idoneus) was probably isolated there by the Vashon glaciation and developed its characters while isolated. The other race, leucodonta, was probably widely spread in Wisconsin Time. Beavers are present in Moses Lake, in almost the center of the Columbian Plateau. Beavers might well have lived in the streams of melt water that emerged from the Wisconsin Glacier. The beavers of western Washington, save those in the extreme southwest, are like the beavers of eastern Washington. It seems likely that the race leucodonta originated north of the state of Washington and was forced southward by the Vashon-Wisconsin glaciers. This northern race, adapted to boreal conditions, competed with the resident coastal race, idoneus, and occupied much of its range. The distribution of the races of muskrat in Washington closely resembles that of the beavers.

Onychomys leucogaster.—The desert-dwelling grasshopper mouse has doubtless entered eastern Washington and the Yakima Valley from eastern Oregon at a relatively recent time.

Reithrodontomys megalotis.—The harvest mouse, like the grasshopper mouse, seems to have entered Washington from Oregon at a relatively recent date. Within the last ten years it has extended its range into the Okanogan Valley in British Columbia.

Peromyscus maniculatus.—Six subspecies of Peromyscus maniculatus occur in the state of Washington. The geographic range of one of these (rubidus) lies mainly in the states of California and Oregon and includes, so far as is known, a single small island in the Columbia River that is politically within the state of Washington. Another (hollisteri) is restricted to certain islands in northern Puget Sound and obviously has become subspecifically differentiated in postglacial time. The remaining four subspecies, namely oreas, austerus, artemisiae and gambelii, have extensive geographic ranges. These subspecies are not confined to their geographic ranges by geographic barriers. Deer mice occur in the deep forests and the open desert, on high mountains and in low valleys, and are almost everywhere the commonest species of mammal present.

The study of several populations of deer mice from any general area usually shows small but constant differences between them. [Dice] (1939: 21) studied stocks of deer mice from nine localities in southeastern Washington and found significant differences between several of them. A statistical study of mice from the San Juan islands shows that the population of almost every island is different in one or more respects from the mice of any other island. Geographically separated populations of "wild caught" mice of the subspecies austerus, of the mainland, were statistically compared and significant differences were found between these populations, too. Small, differentiated populations are to be found in many parts of the state, and each subspecies appears to be an assemblage of such tiny genetic units.

These genetic units probably are the microgeographic races of Debzhansky (1937). They have been intensively studied by [Sumner] (1917 A, B) and [Dice]. An especially important paper by the latter author (1940) summarizes much of the available information on speciation in Peromyscus and clearly discusses the microgeographic races of Peromyscus.

The numerous microgeographic races of Peromyscus maniculatus in Washington present diverse combinations of characters which could result from the random fixation and elimination of genes ([Wright]. 1932: 360-362). Such a hypothesis, however, requires at least partial isolation of the populations involved. The mechanism of such isolation, in such populations of deer mice as we have studied, is not readily apparent. Some microgeographic races are not separated by noticeable geographic or ecologic barriers and the distance between their ranges is not too great to be traversed by a deer mouse. The tendency to remain on a home range may have the same effect as isolation would be supposed to have.

The work of [Murie] and [Murie] (1931: 200-209, 1932: 79) is enlightening in this respect. These authors found that mice residing in a locality tended to remain in that locality; individuals trapped and marked were retaken in the same locality a year later. Individuals released some distance from the point of capture remained where released or returned to the point of capture. Transported individuals did not spread at random. The home instinct was developed in young as well as in old mice. Two mice in the gray pelage, four to eight weeks old, returned to their home ranges from distances one and two miles away. The authors fix the home range of an individual Peromyscus m. artemisiae in Teton County, Wyoming, at approximately one hundred yards in diameter.

This home-range instinct is essentially a lack of incentive for individual mice to emigrate to new localities where mice of the same species are already established. This may partly account for the microgeographic races of deer mice in Washington.

[Dice] (1939: 21) pointed out that, except in color, the differences in nine stocks of mice from southeastern Washington could not be correlated with environmental factors. We have found this to be true of microgeographic races throughout the state of Washington.

Of the four subspecies of deer mice that occupy extensive geographic ranges in Washington, one, oreas, is a long-tailed form that seems not to intergrade with austerus, a neighbor in western Washington that has a tail of moderate length. These two and gambelii, a short-tailed form with which oreas intergrades, are easily distinguished. In eastern Washington two short-tailed subspecies, gambelii and artemisiae, are currently recognized. The taxonomic relationships of these two subspecies are complex. The subspecies gambelii has an extensive geographic range in Oregon and California. These mice, with short tails, occur in the Wallula Water Gap of southeastern Washington and on the Columbian Plateau. To the west the desert conditions of the Columbian Plateau fade into the Transition Life-zone forests of the eastern Cascade Mountains. The pale, short-tailed desert mice (gambelii) gradually change to the dark, long-tailed subspecies, oreas, that occupies the Cascade Mountains.

North of the Columbian Plateau, in northeastern Washington, the deer mice are darker and relatively longer-tailed than on the Columbian Plateau. Some populations are distinctly reddish, almost as reddish as oreas. Although assigned to artemisiae, they are almost identical with populations of deer mice from the eastern Cascade Mountains, known to be intergrades between oreas and gambelii. This fact, and the presence of surprisingly oreas-like characters in some microgeographic races in extreme northeastern Washington, may indicate that the race called artemisiae is a group of intergrades between gambelii and an oreas-like mouse that has become extinct.

Intergradation between gambelii and artemisiae is normal and takes place gradually where the ranges of the two subspecies meet. The same is true of intergradation between oreas and gambelii in the eastern Cascade Mountains. West of the Cascade Mountains the range of oreas meets the range of austerus. These two subspecies appear not to interbreed in nature, since no intergrades were taken at any of the numerous localities in western Washington where the mice were trapped. Pure populations of the two subspecies exist within a few miles of each other. In the valley of the Skykomish River, in the western Cascades Mountains, from the town of Skykomish, King County, to the lowlands to the west, only austerus was found. In the coniferous forests of the mountains above Skykomish, only oreas was taken. Several pairs, each an oreas and an austerus of the other sex, were kept from four to six months, and one pair was kept for a year, but they did not reproduce. The oreas were from the upper Skykomish Valley and the austerus were from Seattle, King County. Along the border of the ranges of the two subspecies in the Skykomish River Valley, a definite habitat preference was noted. The coniferous forests were occupied by oreas and brush or deciduous forests by austerus. Within the range of austerus and within the range of oreas only one subspecies is found whether the habitat be coniferous forest or thickets of alder and willow, but where the ranges of the two subspecies meet austerus occurs only in the thickets of aspen and willow and oreas occurs only in the coniferous forest.

The morphological characters that separate oreas from austerus, namely, larger size, richer color, and longer tail, are all features that might be associated with a more arboreal existence in dark, coniferous forests. Our observations show that oreas is, to a large extent, arboreal. Traps nailed to tree trunks six to eight feet from the ground and set for flying squirrels often caught oreas in the Skykomish River Valley. On one occasion I walked up a leaning tree trunk to set a trap, fifty feet from the ground on the trunk of another tree that was upright. An oreas was found in this trap the next morning. [Svihla] (1933: 13) relates how a specimen of oreas that escaped from a live trap took refuge in a tree when pursued. We have set numerous traps for flying squirrels in the area about Puget Sound. As far as memory and field notes serve, we have never taken austerus in these traps. Our observations on the habits of austerus are much more abundant than those on oreas, but for austerus no evidence of arboreal activities has been obtained.

There are, then, two subspecies that do not interbreed, each capable of existing in any ecologic niche that will support deer mice. Where the ranges of the two subspecies come together, they compete. The large size, richer color, longer tail, and perhaps arboreal habits of oreas give it an advantage in coniferous forests. The small size and dark color of austerus give it an advantage in other habitats, especially, perhaps, in winter, when the deciduous trees have shed their leaves.

The differences separating austerus from oreas would be expected to have developed under complete isolation. That oreas developed from austerus or austerus from oreas seems impossible. A glance at the distribution map (Fig. 107) shows that the range of austerus clearly separates the range of oreas into two segments. The range of austerus tapers out to the north, east and west. On the south austerus intergrades with rubidus from Oregon, a subspecies from which it is but slightly differentiated.

The geographic behavior of the four subspecies of deer mice that occupy extensive areas in Washington may be summarized as follows: P. m. gambelii occupies southeastern Washington and intergrades normally with oreas in the eastern Cascade Mountains and with artemisiae at the northern edge of the Columbian Plateau; artemisiae, occupying northeastern Washington, closely resembles populations of mice that are known to be intergrades between oreas and gambelii and itself intergrades with both oreas and gambelii; oreas occupies most of western Washington, intergrades with its neighbors artemisiae and gambelii to the east, but does not intergrade with austerus, its morphologically more similar neighbor in the west; austerus occupies a range in western Washington that is almost surrounded by the range of oreas, a subspecies with which it apparently does not interbreed.

The relations of these four subspecies appear to be the result of certain great changes in the range of deer mice in the Pacific Northwest that occurred during and since the last Pleistocene glaciation. We reconstruct these changes as follows. In the Puyallup interglacial cycle, just previous to the last (Vashon-Wisconsin) continental glaciation, clines, or gradual transitions existed in the ranges of the deer mice along the Pacific Coast. The small, dark, short-tailed mice of the coastal redwood forests of California and Oregon became gradually larger, redder and longer-tailed to the north, climaxing in a large, red, long-tailed form in the spruce forests of southern Alaska and northern British Columbia. A similar cline existed inland. Small, pale, short-tailed mice of the Great Basin became increasingly larger, darker, and longer-tailed to the north, reaching a maximum in the spruce forests of northern British Columbia.

The development and advance of the Vashon-Wisconsin ice sheet exterminated mice over much of British Columbia and the northern United States. Long-tailed northern mice were forced southward and contacted the southern, short-tailed forms. The preglacial clines were thus destroyed.

What might be the southern part of the western cline may be noted in the deer mice of western Oregon today. From the southern coast of Oregon the mice (P. m. rubidus) do become larger, redder and longer-tailed to the north. The climax of this cline is now reached in austerus, of the Puget Sound area of Washington. The cline is not continued farther northward because the range of oreas is encountered.

The advance of the Vashon-Wisconsin ice from the north probably forced species of mammals southward, ahead of it, including the long-tailed northern deer mice which generation by generation encountered progressively shorter-tailed forms of resident mice. Perhaps the unfamiliar, and certainly the extremely frigid, conditions in the fore of the glacier exterminated the short-tailed individuals but favored the long-tailed mice, since the latter originally were adapted to a boreal environment. The climax of the ice advance found the glaciers just within the political limits of the United States and found the long-tailed mice spread before the ice front.

In western Washington the Vashon glacier advanced as far south as the southern edge of the Puget Sound area. Long-tailed northern mice advancing before it reached the Columbia River. This glacially swollen stream served as a natural barrier and prevented their southward extension. At this time the northern mice had traversed more than half the length of the original western cline. The northern mice, originating in a boreal habitat a thousand miles away, were unable to interbreed with the southern mice and such individuals as might have crossed the Columbia River never became established in Oregon. During the existence of the glacier in western Washington, the long-tailed northern emigrants competed with the resident deer mice of western Washington to the total elimination of the resident mice. The retreat of the Vashon Glacier from Washington found the northern mice in complete control of that part of the state from the Pacific Ocean to the Cascade Mountains.

In eastern Washington the Wisconsin Glacier advanced south to the northern edge of the Columbian Plateau. Northern mice advancing before it probably did not survive on the treeless plateau but existed in forested areas of northern Idaho and driftless areas of northern Washington. No natural barriers separated the northern mice from the pale, short-tailed forms. The nonuniform topography perhaps allowed more mingling of the two types where climatic conditions permitted. Intergradation in some places as well as competition and elimination of one form or another in other places occurred. Following the withdrawal of the Vashon ice and the establishment of soil and forests on the deglaciated land, the long-tailed mice of western Washington (P. m. oreas) apparently spread northward, unhindered by competition, until they reached southern Alaska. The deep coniferous forests of western Washington presented conditions acceptable to oreas and it persisted there despite postglacial changes in climate.

Postglacial changes in climate did, however, permit the dark, short-tailed mice (rubidus) to cross the Columbia River and to become established in suitable habitats, namely the deciduous jungles of the river valleys. From these points the mice spread northward through the lowlands of western Washington, infiltrating the range of oreas, competing with it, and driving it from the lowlands. This movement is in progress today. By logging and clearing of lands for agriculture man has considerably speeded the invasion of the southern mice. Slight differentiation of the short-tailed mice north of the Columbia River (austerus) separates them from their parent race, rubidus.

In the dense forests along the Pacific Coast of Washington, austerus did not become established. This area includes most of the land west of Puget Sound. There is a narrow band of austerus that extends along the eastern and part of the northern edge of the Olympic Peninsula, where they have probably invaded in relatively recent time.

On the Oregon side of the Columbia River the range of rubidus is continuous from the Pacific to the Cascades. On the Washington side of the river, oreas extends from the Pacific to eastern Wahkiakum County, where the range of austerus starts. At the border of the ranges of the two subspecies, ecological conditions determine the ranges; oreas occurs in the Douglas fir and hemlock forests and austerus occurs in the jungles of alder and salmonberry in the stream valleys. The range of austerus extends from eastern Wahkiakum County east along the Columbia, to western Klickitat County. In a north-south strip across the Columbia, through the ranges of rubidus in Oregon and austerus in Washington, normal intergradation is apparent. By gradual degrees rubidus changes to austerus. In a north-south strip farther west, through the ranges of rubidus and oreas, the same transition of the Oregon rubidus is seen, namely an approach toward austerus. The cline is, of course, abruptly terminated by the range of the dissimilar oreas.

On Puget Island, a small island lying in the Columbia River in western Wahkiakum County and politically within the state of Washington (see [Scheffer], 1942) a population of deer mice occurs that resembles rubidus more closely than austerus. This island lies in the river between the ranges of rubidus and oreas. The lack of intergradation between these two subspecies has probably kept the Puget Island population pure rubidus. Puget Island is a junglelike lowland locally known as "tideland."

The San Juan Islands of northern Puget Sound were thoroughly glaciated in Wisconsin Time and probably were under thousands of feet of ice when the Vashon Glacier was at its maximum extent. The subspecies of deer mouse occurring there now is hollisteri, a race similar to oreas in color, body size and cranial characters and probably derived from oreas. P. m. hollisteri differs from both oreas and austerus in its much shorter tail. Shortness of tail is apparently a product of insularity in northwest coastal mice. The transition from long-tailed mainland mice to short-tailed island mice is shown by [Hall] (1938A: 461). When oreas first occupied the area about Puget Sound (this area is occupied by austerus today) some individuals probably reached the San Juan Islands soon thereafter. Contact between oreas and hollisteri is now prevented by the presence of austerus between their ranges. Of course, a water barrier separates austerus from hollisteri but austerus does occur in pure form on some islands in Puget Sound (not on any of the San Juan Islands), for instance, on Whidby Island. One wonders why austerus has not established itself on some of the San Juan Islands but considering the degree of difference between hollisteri and austerus, I doubt that the two would interbreed if they did occur together.

On Vancouver Island, British Columbia, a short-tailed, austerus-type of mouse occurs in the lowlands and a long-tailed, oreas-type of mouse in the mountains. Vancouver Island is a large island (16,400 square miles). Apparently a stock of austerus from the mainland reached Vancouver Island and were able to find suitable habitat and compete with and drive out the established oreas in the manner that they probably did in the western Washington lowlands. The large Vancouver Island offers far more variety of habitat and opportunity for establishment of emigrating mice than do the smaller San Juan Islands, the largest of which is Orcas (57 square miles).

Following the withdrawal of the Wisconsin ice from eastern Washington, numerous minor movements and adjustments of deer mice seem to have taken place. Long-tailed, oreas-type of mice were exterminated on the Columbian Plateau if, indeed, they ever became established there. Long-tailed mice did apparently become established in driftless areas and forested areas to the south of the drift border. With the establishment of soil and forests on the deglaciated land, the short-tailed gambelii and the long-tailed mice became thoroughly intermixed. In some areas, especially near the type locality of artemisiae, the gambelii characters of the mixture predominate at the present time. Deer mice from the Okanogan Valley differ from gambelii only in slightly larger size and darker color. In other areas, notably near Metaline, Pend Oreille County, the oreas characters of the mixture dominate at the present time. Mice from here are large and red and differ from typical oreas in having relatively short tails. Other less marked segregations of characters are numerous, in Idaho and British Columbia as well as in Washington. [Cowan] (1937) has described Peromyscus m. alpinus, isolated in a mountainous area of British Columbia. This seems to be a form derived from oreas-type stock.

With the reëstablishment of soil and forests on the deglaciated land of British Columbia north of Washington, a northward extension of the gambelii-oreas mixture occurred. Another invasion was taking place at this time, however. Peromyscus m. arcticus spread onto the deglaciated land from the north or east, ahead of artemisiae (the gambelii-oreas mixture). This new invader intergraded with artemisiae as well as with oreas. Further collecting and studies are required in this area before the relationships of the three subspecies can be completely understood.

If geographic ranges are assigned to the named subspecies of deer mice that occur in Washington, it must, in part, be done arbitrarily. The deer mice of the San Juan Islands are all referred to the subspecies hollisteri. Only Puget Island, Wahkiakum County, is considered to be inhabitated by rubidus. The boundary between the ranges of austerus and oreas is sharply defined and further collecting by resident naturalists should result in detailed mapping of the boundary.

The ranges and distribution of the deer mice of eastern Washington are less clearly defined than those of western Washington. Peromyscus m. gambelii exists in its purest state on the Columbian Plateau. Here the Columbia River makes a convenient boundary to the west. Pure Peromyscus m. oreas exist in the Cascade Mountains. In the area between the Columbian Plateau and the Cascades the deer mice are variously intermediate between gambelii and oreas and, over most of the area, are nearest to gambelii. This might be considered a natural area of intergradation such as commonly occurs between the ranges of subspecies. These intergrades, however, are similar to Peromyscus m. artemisiae and the area occupied by these intermediates is connected on the north with the range of artemisiae. Thus [Osgood] (1909: 61) regards specimens from Easton and Wawawai, in the area of intergradation, as artemisiae or intergrades between gambelii and artemisiae. [Taylor] and [Shaw] (1929: 22) include the entire area of intergradation in the range of artemisiae. This treatment, although convenient to the student of geographic variation, is apt to conceal the evolutionary and historical influences. These influences may be appreciated better if the intergrades from each locality are referred to the subspecies they most closely resemble.

The specimens upon which the name artemisiae was based came from a narrow tongue of zonally lower country that extends northward from the range of the lighter-colored gambelii. As might be expected, topotypes are lighter in color than specimens from the north, west and east. Nevertheless, the type locality is within a geographic area that is occupied principally by a darker race, artemisiae, to the north of gambelii. The topotypes of artemisiae may be considered to be intermediate between gambelii and the darker, northern race. Thus the name artemisiae becomes available for the mice of the general area in question. The mice of the area immediately to the east of the type locality, in Washington and presumably in British Columbia and Idaho also, are essentially a mixture of the subspecies gambelii and a now mostly extinct and unnamed race that probably resembled oreas. Local variations of populations from within this area are extreme but some segregation of color and length of tail has taken place. Mice from mountainous areas resemble oreas while mice from the lowlands resemble gambelii, or, more exactly, mice from coniferous forests resemble oreas while mice from other areas resemble gambelii.

South of the area of racial mixture in northeastern Washington, in the Blue Mountains of southeastern Washington, the deer mice are like gambelii except in slightly darker color. Mice from the Blue Mountains are darker and browner than gambelii, not more reddish. There is no indication of adulteration with oreas stock. Since the Blue Mountains are a forested area and are far south of the drift border, we suppose that deer mice existed there through the last glacial period and that their dark color is an adaptation to forest habitat.

Mice similar to those of the Blue Mountains have an extensive range in Idaho ([Davis] 1939: 290). These mice have relatively uniform racial characters and constitute a "good" subspecies.

At present the deer mice of northern Washington, southeastern British Columbia, northern Idaho, northeastern Oregon, western Montana and northwestern Wyoming are called artemisiae. The mice of this extensive area are, however, of two genetic types: that type with mixed racial characters that lives in northeastern Washington and probably also farther east along the Wisconsin drift border, and that type that occurs farther south in Idaho and seems to constitute a stable subspecies.

The separation of these two types may be desirable. Detailed study of the deer mice from the area now assigned to the range of artemisiae may show that the name subarcticus (Peromyscus texanus subarcticus [Allen], 1899) is applicable to the southern form. The type with mixed racial characters must be called artemisiae. If the two types are eventually separated, the mice from the Blue Mountains of Washington will be referable to the southern form.

Neotoma cinerea.—The wood rat found over most of Washington. Neotoma c. occidentalis, probably entered the state from eastern Oregon early in the Recent and spread over most of the state. The wood rat of the Blue Mountains (alticola) probably developed from occidentalis.

A coastal race of the wood rat (fusca) occurs in western Oregon. This race, if it occurred in western Washington in pre-Vashon Time, was eliminated in Vashon Time or subsequently. In Oregon it lives in deep forests ([Bailey], 1936: 174). In Washington occidentalis occupies but a small part of the ecologic niche occupied by fusca in Oregon. Elimination of fusca from Washington through competition with occidentalis seems highly improbable. Should fusca ever cross the Columbia River and become established it would probably spread to a considerable part of western Washington.

Synaptomys borealis.—The lemming mouse seems now to be retreating northward and was an arctic species forced southward by the Vashon-Wisconsin glaciers. Unlike other alpine species, it seems to be unable to exist for long in isolated mountain areas.

Phenacomys intermedius.—The heather vole, like the lemming mouse, probably was forced southward by the Vashon-Wisconsin glaciers. In the Cascade and Rocky mountains it found suitable habitat and spread southward to almost the lower end of the Sierra Nevada in California. The Cascade race moved eastward on the Puget Bridge to the Olympic Mountains after the retreat of the Vashon ice, and northward in the Cascades. Northeastern Washington was reinvaded by the subspecies of the Rocky Mountain Fauna.

Clethrionomys gapperi and CALIFORNICUS.—The two species of red-backed mouse found in Washington were probably distinct in pre-Vashon Times. At the maximum extent of the Vashon ice, californicus was probably found in western Oregon and gapperi in the Blue Mountains, where idahoensis was developed, and in the southern Cascades (cascadensis). During or shortly after Vashon Time, gapperi crossed the Puget Bridge to become established in the Olympic Mountains. After the retreat of the ice, gapperi moved northward and eastward from the Cascades and californicus crossed to western Washington from Oregon and displaced gapperi from the lowlands.

[Hinton] (1926: 215) separated the American Clethrionomys into three groups, suggesting that Old World counterparts of each group exist. [Davis] (1939: 308) gives an excellent analysis of the emigrational history of the American species, and points out the close relationship of the Siberian and Arctic-American forms. He suggests that the rutilus group invaded Arctic-America from Siberia at the close of the last glaciation.

Two other groups are recognized by [Davis], who assumes that both arose from a common ancestral stock and divided into two stems, one of which (gapperi group) followed the main Rocky Mountain course southward and worked eastward across Canada while the other (californicus group) followed down the Pacific Coast. [Davis] states, "This southward extension of range in America probably took place in the Pleistocene, but almost certainly the present southern range of the genus in the West was not reached until late in, or after, that period."

Our studies of the Clethrionomys of Washington indicate the essential correctness of [Davis]' conclusions. The separation of the two groups, however, probably was caused by southward moving glaciers and the separation of the mice into two stocks closely paralleled the divergence of other groups, such as that of the snowshoe rabbits. The two groups of red-backed mice are more sharply separated than was thought by [Davis]. The intermediate color of the back of C. g. idahoensis, mentioned by [Davis], seems to be merely coincidental. The essential difference in the two groups is the sharply marked red band of the gapperi group as opposed to the general red area on the dorsal surface of the californicus group. Clethrionomys gapperi nivarius has been considered a derivative of occidentalis because the range of the latter surrounds the Olympic Mountains, where nivarius is found. Considering the immediate post-Pleistocene movements of mammals from the Cascades to the Olympic Mountains, so clearly illustrated in Thomomys, Tamias amoenus, and Phenacomys, a means is indicated by which Clethrionomys of the gapperi group might have reached the Olympics. The apparent lack of intergradation between occidentalis and nivarius gives proof of their relatively distant relationship. C. nivarius seems not to have been derived from occidentalis, and apparently does not belong to the californicus group. It belongs instead to the gapperi group, and I consider it to be a subspecies of gapperi. In no sense is it intermediate between the two groups. The other form considered by [Davis] to be intermediate between the two groups is caurinus. This mouse has not yet been taken in Washington, although it may eventually be found on Point Roberts, on the Fraser River delta. Its distribution is paralleled by that of many other mammals that are definitely not of the Pacific Coastal Fauna.

The californicus group, I feel, contains only the races of Clethrionomys californicus, while the gapperi group contains C. gapperi and its races, including caurinus, and possible other species.

Possibly intergradation occurs between C. californicus occidentalis and C. gapperi. Nevertheless, I fail to find evidence of such intergradation. I have taken C. gapperi nivarius and C. californicus occidentalis within ten miles of each other, but each retained its distinctive characters with no evidence of intergradation. In the case of C. gapperi saturatus and C. californicus occidentalis the proof is less conclusive. In spite of numerous attempts to trap Clethrionomys in the area geographically intermediate between their ranges, I have taken none. Though common along the coast, occidentalis becomes progressively scarcer to the east, being rare in the vicinity of Seattle and apparently absent from the western base of the Cascades. So far as is known, the ranges of caurinus and occidentalis are separated by the Fraser River.

Microtus pennsylvanicus and MONTANUS.—The Pennsylvania meadow mouse is closely related to Microtus montanus. Certain races of montanus, notably those from southern Oregon, California, and northern Nevada, closely resemble pennsylvanicus externally and cranially. From the central part of its range northward, montanus becomes progressively less like pennsylvanicus. The races nanus and canicaudus are quite different from pennsylvanicus both externally and cranially, and in addition the anterior loop of the second molar is less constricted; often it is not constricted at all. Microtus pennsylvanicus and Microtus montanus occur together over parts of the northern Rocky Mountains. Where the two species came together, pennsylvanicus occurs with races of montanus that are most unlike it.

Microtus pennsylvanicus kincaidi closely resembles races of Microtus montanus that occur in southern Oregon, California, and Nevada. It is larger, darker, and longer-furred than Microtus pennsylvanicus funebris from Washington. Seemingly pennsylvanicus and montanus diverged previous to Vashon-Wisconsin Time. The stock that gave rise to montanus spread over the Great Basin while pennsylvanicus ranged farther east. Some of the montanus stock worked northward in the Rocky Mountains. Microtus pennsylvanicus had meanwhile moved westward to the Rocky Mountains. The two stocks met and behaved as full species.

Microtus pennsylvanicus probably occupied northeastern Washington in the interglacial cycle preceding the Recent. The advance of the Wisconsin ice eliminated most of these mice. The glacier dammed the Columbia River and caused it to turn southward from its basalt-marginal course and take a path over the Columbian Plateau. Along this glacial river a population of Microtus persisted to become kincaidi.

While the Wisconsin ice was at its maximum extent, Microtus montanus from the Blue Mountains crossed the Simcoe Bridge to the Yakima Valley and the eastern Cascade Mountains. The closing of the Simcoe Bridge isolated these mice, which subsequently became slightly differentiated, as canescens. Another stock moved westward along the Columbia River to western Oregon. This stock is now called Microtus canicaudus but is probably racially rather than specifically distinct from Microtus montanus nanus.

With the retreat of the Wisconsin ice, montanus extended its range northward from the Yakima Valley along the eastern Cascade Mountains to extreme southern British Columbia. Microtus pennsylvanicus funebris entered northeastern Washington with other elements of the Rocky Mountain Fauna.

At present, pennsylvanicus occurs in northeastern Washington while montanus is found in southeastern Washington and the eastern Cascade Mountains. The Okanogan River Valley separates their ranges. Eventually montanus may extend its range to northeastern Washington and pennsylvanicus to the Cascades, the two forms occurring together as they do in Montana, Idaho and Colorado. The isolation of kincaidi on the Columbian Plateau seems complete and the probability of its range reaching that of its related species seems slight.

Microtus longicaudus.—The later distributional history of the long-tailed meadow mouse is not yet clear.

Microtus townsendii.—This Pacific Coastal species probably lived west of the Sierra Nevada-Cascade Mountains since the early Pleistocene. It has extended its range northward since the retreat of the Vashon ice and has reached some of the islands in Puget Sound and the Strait of Georgia. This species seems to be related to Microtus richardsoni but the two species probably separated at an early time.

Microtus richardsoni.—The water rat of the Cascade Mountains seems to be have been forced southward into Washington and Oregon by the descent of the Vashon-Wisconsin glaciers where it became isolated from the water rat of the northern Rocky Mountains. After the retreat of the ice, both forms have moved northward. [Bailey] (1900) records macropus from Bonner County, Idaho, not far from northeastern Washington but in Washington up to this time, macropus has been recorded only from the Blue Mountains of the southeastern part of the state.

Microtus oregoni.—The later historical distribution of the creeping mouse was probably the same as that of townsendii.

Lagurus curtatus.—The distribution of this species of the Great Basin Fauna has probably changed little if any since the late Pleistocene.

Ondatra zibethicus.—The distribution of the two races of muskrat that occur in Washington is almost exactly that of the beavers. Probably one form was isolated in southwestern Washington and northwestern Oregon during Vashon Time and another, more adaptable, race occurred in eastern Washington. After the retreat of the ice the adaptable race spread widely but the muskrats of the lower Columbia River changed their range little or not at all.

Aplodontia rufa.—The race of Aplodontia found in the Cascades of Washington was probably confined to the southern Cascades in Vashon Time and has since spread northward to reoccupy the range as far north as southern British Columbia.

The presence of a mountain beaver in western Washington that is indistinguishable from the race rufa, found in the Cascades of Oregon, is most surprising. In Oregon, pacifica occurs in the western lowlands and rufa in the mountains to the east. In Washington rufa occurs in the western lowlands and rainieri in the mountains to the east.

The offset in range of rufa seems best explained by assuming that all of western Washington was once occupied by mountain beavers (rufa) that spread from the Cascades of Oregon to the Cascades of Washington and thence to the western Washington lowlands. This must have occurred early in the interglacial cycle preceding the Vashon Glaciation. While confined to the southern Cascades, rainieri developed the larger size that now separates it from the ancestral rufa that occurs to the west and south of it.

Zapus princeps.—The coastal race of the jumping mouse was probably distinct from the more inland population before Vashon-Wisconsin Times. The differences between them were probably accentuated while the Vashon-Wisconsin glaciers separated their ranges. The western race (trinotatus) was isolated in the southern Cascades and southwestern Washington. After the retreat of the glaciers, trinotatus moved northward through western Washington and the Cascades into British Columbia. The race kootenayensis of the adjacent Rocky Mountains moved eastward through northeastern Washington to the Cascades. The race oregonus, found in the Blue Mountains, has probably been resident there since it evolved from the populations to the east.

Erethizon dorsatum.—I have inadequate basis for speculation concerning the historical distribution of the porcupine.

Ochotona princeps.—The descent of the Wisconsin ice separated the western pikas into two populations. One was confined to the Cascade-Sierra Nevada system and another to the Rocky Mountains. Two races are now found in the Cascades of Washington. One, brunnescens, inhabits the higher Cascades and another, fenisex, the eastern edge of the Cascades. The range of brunnescens extends southward into Oregon while the range of fenisex extends farther north in British Columbia than does that of brunnescens. The principal difference between the two races is the smaller size and paler color of fenisex. In Washington, fenisex occupies a slightly more arid habitat than brunnescens. Further, fenisex lives in talus principally of basaltic rock while brunnescens lives in talus of granitic rock. The basaltic talus is more finely fractured, offering smaller crevices in which pikas can conceal themselves. The granitic rock, on the other hand, forms talus composed of fragments of large size. Freshly fractured granite is pale, whitish gray. After weathering, however, it becomes blackish as the more soluble, pale feldspars are removed, leaving the black hornblend and biotite exposed. Freshly fractured Columbian basalt is blackish but, after weathering, becomes rusty, reddish brown.

In Washington the two races maintain their distinctiveness because selective factors in the basalt talus of the eastern Cascades favor the smaller size and paler color of fenisex while in the higher Cascades, selective factors in the granitic batholith favor larger size and darker color.

The present range of brunnescens in Oregon indicates that this race was the pre-Wisconsin resident of the Cascades of at least southern Washington. Probably fenisex evolved in the arid interior of British Columbia. In color fenisex is intermediate between the dark brunnescens and the pale cuppes of the western spurs of the Rocky Mountains. Probably fenisex was forced southward into the eastern Cascades by the Wisconsin ice and inhabited the area east of the range of brunnescens. This eastern area was not occupied by brunnescens because the basaltic talus was of small size. After the retreat of the ice, fenisex (adapted to more arid habitat than brunnescens), spread northward to the relatively dry valleys of the interior of British Columbia.

The distinctness of brunnescens and fenisex is maintained by selective factors of the habitats they occupy but the zone of intergradation between the two is broad. A tendency towards paleness is noticeable in specimens from as far west as the eastern side of Mount Rainier.

The pikas in the Rocky Mountain area have given rise to a number of races. The pale, small race of northern Idaho, cuppes, entered northeastern Washington with other members of the Great Basin Fauna after the retreat of the ice.

Lepus townsendii.—The white-tailed jack rabbit has probably lived on the Columbian Plateau ever since or even before the time when the Wisconsin ice bordered the plateau on the north.

Lepus americanus.—Snowshoe rabbits were probably spread over forested parts of Washington in pre-Wisconsin time. A coastal race, washingtonii, was probably distinct from the remainder of the species at an early time. It, and its kindred races klamathensis and tahoensis, are very different from races derived later from the Rocky Mountain Fauna. From this it is deduced that washingtonii was a member of the Pacific Coastal Fauna before the advance of the last continental glaciers.

The snowshoe rabbits now found in the Cascade Mountains of Washington are racially distinct from populations occurring to the north and east, but are more closely related to the northern and eastern rabbits than they are to washingtonii. This race, cascadensis, probably lived in the area north of the state of Washington in pre-Wisconsin interglacial time. The snowshoe rabbit of northeastern Washington was probably a race having an extensive range in the Rocky Mountains from which pineus in the Blue Mountains developed. The descent of the Vashon-Wisconsin glaciers found washingtonii restricted to western Oregon. It might have persisted also in southwestern Washington but, had this been the case, we would expect a broader zone of intergradation between washingtonii and cascadensis than actually exists.

The glaciers forced cascadensis southward into the Cascades of southern Washington. The difference between washingtonii and cascadensis and the narrow zone of intergradation between them, indicate that the two races were not in contact in pre-Vashon Time. The presence in the Cascades of Oregon of a race related to washingtonii rather than cascadensis also supports this view. The snowshoe rabbits of northeastern Washington were probably eliminated from areas where the ice was in place. The effect of the glaciers in nearby areas was probably less on snowshoe rabbits than upon other species.

Following the retreat of the glaciers, washingtonii reinvaded western Washington and spread northward through the lowlands to the Fraser River. In the Cascades, cascadensis moved even farther north. L. a. pineus of the Rocky Mountain Fauna invaded northeastern Washington from adjacent areas to the south. Another race, columbiensis, spread from the interior valleys of British Columbia to the western part of northeastern Washington in probably relatively recent times. The post-Wisconsin history of the distribution of this race is uncertain.

Lepus californicus.—The black-tailed jack rabbit occurs throughout the sagebrush areas of eastern Washington, except in the Okanogan Valley. It invaded Washington from the south recently ([Couch], 1927: 313). The first blacktails were thought to have entered Walla Walla County about 1870. Here they were checked by the Snake River. About 1905 they crossed the Snake River, on ice, and by 1920 had spread over much of the Columbian Plateau. In January, 1920, they crossed the Columbia River in two places, on ice jams, and by 1927 had spread north and west over the sagebrush areas between the Columbia River and the Cascade Mountains. When [Couch], in 1927, published his account, he predicted that the blacktail would eventually spread to the Okanogan Valley. This has not yet occurred although it is still to be expected.

It should be noted that the migrational history of the black-tailed jack rabbit is known only because the animal is large, spectacular, and diurnal, and therefore noticed by resident ranchers, and because the facts came to the notice of a competent biologist. Migration of a less conspicuous mammal, for example, a mouse, would rarely be detected.

Sylvilagus nuttallii.—The cottontail might have been resident on the Columbian Plateau during Wisconsin Time but probably it invaded, or perhaps reinvaded, the Plateau from eastern Oregon in the Recent.

Sylvilagus idahoensis.—Too little is known about this rabbit in Washington to hazard a guess as to its recent distributional history.

Cervus canadensis.—The elk emigrated from Siberia to North America in the late Pleistocene but previous, certainly, to Vashon-Wisconsin time. Probably the coastal race was distinct from the interior population in the preceding interglacial cycle. The descent of the last continental glaciers, in Washington, separated the elk of the Pacific Coastal Fauna from the Rocky Mountain Fauna. After the retreat of the ice the coastal race moved northward to southern British Columbia and the Rocky Mountain race moved northward and westward through British Columbia. Northeastern Washington was reoccupied by the Rocky Mountain elk.

Remains of elk have been found associated with human artifacts on the northern part of the Columbian Plateau. The plateau is poorly suited to elk but a few may have persisted there until late historic time. The remains may have been brought by Indians from northeastern Washington. The remains included teeth and portions of the skull and it seems unlikely that these would have been carried any great distance.

Odocoileus hemionus.—The American deer probably evolved in North America. In this respect they are unlike the elk, moose and caribou, all of which emigrated from Asia to America in the Pleistocene. Odocoileus hemionus and virginianus probably diverged from a common stock in the Pliocene.

The black-tailed deer was probably a member of the Pacific Coastal Fauna at an early time and distinct from the mule deer before the last interglacial cycle. Probably the mule deer lived in the eastern Cascades and on part of the Columbian Plateau in Wisconsin Time. They occur on the plateau in limited numbers at present and their remains have been found associated with human artifacts in the Grand Coulee area.

Odocoileus virginianus.—The white-tailed deer ranges from the Atlantic to the Pacific and from Canada to Mexico. The species was probably abundant in the Pacific Northwest in the Pleistocene, perhaps in Vashon-Wisconsin time, but has since largely given way to the black-tailed and mule deer. The race O. v. leucurus now occupies an extremely small range. The accounts of early naturalists indicate that it was more abundant and had a wider range 100 years ago. Probably leucurus was once an important member of the Pacific Coastal Fauna.

The inland race, ochrourus, is a typical member of the Rocky Mountain Fauna. It and leucurus were probably derived from a common ancestor in the late Pleistocene.

Alce americanus.—The moose occurs in Washington as a casual wanderer from the Rocky Mountain Fauna to the east.

Rangifer montanus.—The caribou occurs in northeastern Washington as a winter migrant from the north. It was probably of more regular and extensive occurrence in the past.

Antilocapra americana.—The antelope probably was a casual wanderer to southeastern Washington and perhaps to the Columbian Plateau from eastern Oregon before white man reached Washington.

Bison bison.—The buffalo, like the antelope, probably occurred in southeastern Washington and on the Columbian Plateau only as a casual wanderer from Oregon in postglacial time.

Ovis canadensis.—Mountain sheep reached North America from Asia in the Pleistocene. By Vashon-Wisconsin Time they had spread southward, perhaps to Mexico. The descent of the Vashon-Wisconsin ice in Washington presumably separated the canadensis and californiana type of sheep, the former being confined to the Rocky Mountain Fauna and the latter to the Cascade-Sierra Nevada chain and adjacent parts of the Great Basin.

Mountain sheep probably persisted in the southern Cascades of Washington and on the Columbian Plateau during Vashon-Wisconsin times. After the retreat of the ice, these sheep (californiana) moved northward slightly, both in the Cascades and on the Columbian Plateau. Remains of sheep are to be found with human artifacts in the Grand Coulee area today. When white man first reached the state, sheep existed throughout the Cascades and on part of the Columbian Plateau. Only a pitiful remnant remains in the extreme northern Cascades.

Mountain sheep of the Rocky Mountain race probably existed in small numbers in the Blue Mountains of southeastern Washington until historic times. Sheep from the Blue Mountains or adjacent Idaho invaded northeastern Washington shortly after that region was freed from Wisconsin ice. These sheep were exterminated shortly after the coming of the white man.

Oreamnos americanus.—Fossil remains of the mountain goat have been discovered at Washtuckna Lake, associated with those of the lion, horse, and camel. Probably the mountain goat had an extensive range in Washington at the time of a glacial advance previous to the Wisconsin glaciation. In Wisconsin Time the mountain goat was confined to the southern Cascades. Strangely enough, it seems not to have crossed the Columbia River to become established in the Cascades of Oregon. After the retreat of the ice it moved northward through the Cascades.

A mountain goat recently taken in northeastern Washington seemingly wandered to the area from Idaho.

EXPLANATION OF TREATMENT

The order of arrangement of the following accounts is that of [Miller] (1924) with some modifications. For example, the Chiroptera are arranged according to [Tate] (1942), the Sciuridae according to [Bryant] (1945) and the Cetacea according to [Scheffer] (1942). A few other minor changes are included.

Although the principal purpose of this report is to describe and interpret the distribution of the various species and races of mammals that occur in Washington, a brief description and account of the habits of the animals is included. Each species account begins with a description, based principally on external characters. This is followed by pertinent information regarding the range of the species, its relationships within the genus and a brief account of its habits. The habits are dealt with in most detail for the species that are of greatest economic importance.

The accounts of subspecies are largely technical. The account of the type specimen is rather complete. Subspecific diagnoses are brief, stating often only the principal racial characters. Standard external measurements are usually given for each subspecies. All measurements, unless otherwise stated, are in millimeters and weights are in grams. Specimens are adult, unless otherwise stated.

No formal list of specimens examined is included. Localities from which specimens have been examined are usually shown on the distribution maps by solid circles. Open circles indicate localities from which specimens, not examined by me, have been recorded by other persons. Most of these records are published but a few are based on authentic trappers' reports, photographs, or other evidence. Unusual occurrences of animals outside their natural ranges are not shown on the maps. Not every record from well within the range of a subspecies has been plotted, but care has been taken to plot all records of occurrences from peripheral areas.

When more than one race of a species occurs in Washington, specimens from localities where the geographic range of one subspecies meets or approaches that of another are listed as "marginal occurrences" in the paragraph on the distribution of the race to which they are best referred. Marginal occurrences are listed from north to south and from west to east. The authority for the record, if published, is given. When the record is based on specimens examined by the author, the collection containing the specimen is indicated as follows:

(E.S.B.) Ernest S. [Booth] collection. College Place, Washington.

(J.M.E.) J. M. [Edson] collection, Bellingham, Washington.

(K.U.) University of Kansas, Museum of Natural History, Lawrence, Kansas.

(M.V.Z.) Museum of Vertebrate Zoölogy, University of California, Berkeley, California.

(U.S.N.M.) United States National Museum, Washington, D. C. Specimens from the Biological Surveys Collection are included here.

(V.B.S.) Victor B. [Scheffer] collection. United States National Museum, Washington, D. C.

(W.S.C.) Washington State College, Charles R. Conner Museum, Pullman, Washington.

(W.S.M.) Washington State Museum, University of Washington, Seattle, Washington.

(W.W.D.) Walter W. [Dalquest] collection, Seattle, Washington.

In all, 230 kinds (species and subspecies) of mammals are listed for the state of Washington. Of these, 9 kinds (opossum, eastern gray squirrel, fox squirrel, 3 kinds of Old World rats, house mouse, nutria, and eastern cottontail) have been introduced into Washington from elsewhere. The dog of the Indians might be listed as a tenth introduced species. The grizzly bear, the sea otter, the wolf, the moose, one race of mountain sheep, one race of mountain goat, and, if they ever occurred in the state, the pronghorn antelope and bison, are nearly or completely extinct in Washington. Mammals other than cetaceans possibly occurring in Washington, but of which satisfactory record is lacking, are mentioned in a hypothetical list at the end of the accounts of species. Of the 220 kinds of native mammals, known to occur in the state, 23 are marine (4 pinnipeds, 19 cetaceans). The 197 living, native, land mammals include 6 orders, 20 families, 58 genera and 101 full species.

CHECK LIST OF MAMMALS

CLASS MAMMALIA—mammals

ACCOUNTS OF SPECIES AND SUBSPECIES

Didelphis virginiana virginiana Kerr
Opossum

Didelphis virginiana Kerr. Anim. Kingd., p. 193, 1792.

Type locality.—Virginia

Description.—Slightly smaller than a house cat; body in older animals heavy and fat; tail long, naked, scaled and prehensile. Ears large, naked and black with white tips; muzzle elongate and pointed; color of fur variable; overhair usually white and underfur white tipped with black; guard hairs long and coarse but underfur soft and dense; forefoot with opposable thumb; females with abdominal pouch.

Remarks.—The opossum has been introduced from the eastern United States into California and Oregon and has become well established in those states. Recent records from Clear Lake, Skagit County, and South Bend, Pacific County, indicate that the opossum is now resident in Washington and it may be expected to increase and spread ([Scheffer], 1943). The animals may also enter the area about Walla Walla from Oregon. The source of the opossums which have appeared in Washington is not yet known.

Of this animal, Dr. Carl [Hartman] (1923: 347) has written:

"In the popular mind, the generation of no animal is so shrouded in mystery as that of the opossum. Throughout the country, among both whites and negroes, deeply rooted tradition has it that the opossum copulates through the nose and that the female blows the fruit of conception into the pouch. Other myths relating to details of the reproductive process in this species are current among the people.

"The growth of such legends need not surprise one, however, for the early birth of the embryos and the use of the pouch as an incubator certainly challenge the imagination. These phenomena attract the attention because they are unique, differing from the familiar method of rearing the young obtaining among the higher mammals, including man. Familiarity breeds contempt; the ordinary ceases to be marvelous. Thus on account of its rareness and its 'different' character the opossum, our only marsupial, figures in the folklore to a prominent degree."

Neurotrichus gibbsii

[Gibbs] shrew-mole

Description.—The shrew-mole is tiny, possessing a head and body 2-1/2 to 3 inches long and a tail about 1-1/2 inches in length. The body is relatively stout but is less cylindrical than that of Scapanus. The eyes are nearly buried in the fur. The nose is long and pointed. The legs are short and the forefeet wide and powerful. The tail is thick, constricted at the base and clothed with short, stiff bristles. The fur is short and posteriorly directed. In color the shrew-mole is dark slate, almost black.

Fig. 21. [Gibbs] shrew-mole (Neurotrichus gibbsii minor), female in captivity; Seattle, Washington, September 12, 1939. (Fish and Wildlife Service photo by Victor B. [Scheffer], No. 719.)

Remarks.—Shrew-moles inhabit moist habitats from sea level to 8,000 feet. They are burrowing mammals and prefer to live in soft earth, free of sod. In the lowlands of western Washington, shrew-moles are most abundant in damp, shady ravines where the vegetation includes deciduous trees and dense underbrush with but little grass. In the mountains, shrew-moles are usually found near streams or rock slides, where the larger annuals grow densely on soil that is deep, soft, and free of turf. Vertically they range from the Humid Transition Life-zone through the Canadian, and well into the Hudsonian Life-zone.

Fig. 22. Distribution of the [Gibbs] shrew-mole in Washington. A. Neurotrichus gibbsii gibbsii. B. Neurotrichus gibbsii minor.

Shrew-moles are both diurnal and nocturnal. They rest or sleep periodically, the length of their rest or sleep being longer when much food is eaten, and the intervals between their periods of rest or sleep is longer when less food is eaten. Owls and snakes appear to be their principal enemies. Predatory mammals eat some shrew-moles, and probably kill many that they do not eat. Shrew-moles are completely blind, and their long, prehensile nose guides all their activity. Their ordinary movements on the surface of the ground are slow and cautious. When frightened they break into a scuttling rush which ends beneath a leaf or bit of bark where the animal becomes motionless. Shrew-moles, on the surface of the ground, make considerable noise. They construct molelike burrows, but these are not as extensive or complicated as those of moles. The shrew-mole hunts for food in shallow trenches that it makes just under the layer of dead leaves and vegetable debris that covers the ground in their habitat. The food of the shrew-moles includes earthworms, isopods, insect larvae, soft-bodied insects, and other animal matter. Some vegetable matter is eaten.

Breeding takes place at all seasons of the year, save perhaps in December and January. Embryos vary from one to four. The nest of a shrew-mole at Seattle, King County, consisted of a handful of damp leaves in a cavity of a rotten, punky, alder stump. The nest contained four half-grown young.

Neurotrichus gibbsii gibbsii ([Baird])

Urotrichus gibbsii [Baird], Mamm. N. Amer., p. 76, 1857.

Neurotrichus [sic] gibbsii Günther, Proc. Zool. Soc. London, pl. 42, 1880.

Neurotrichus Gibbsii True, Proc. U. S. Nat. Mus., 7 (1884):607, 1885.

Neurotrichus gibbsii [Bryant], Zoe. 1:359, February, 1891.

Neurotrichus gibbsii gibbsii [Miller], U. S. Nat. Mus. Bull., 79:11, December 31, 1912.

Type.—Obtained at Naches Pass, 4,500 ft., Pierce County, Washington, by G. [Gibbs] on July 15, 1854 (see [Dalquest] and [Burgner], 1941); type in United States National Museum.

Racial characters.—Size relatively large; tail relatively long; foreclaws straight on ventral surface.

Measurements.—Two females from Tye, 4,000 ft., Stevens Pass, King County, average: total length, 121.5; length of tail, 45; length of hind foot, 18.

Distribution.—The Cascade Mountains, from British Columbia south, and Destruction Island, Jefferson County. Records of occurrence are Baker Lake (J. M. E.), Tye (M. V. Z.), and Mount Rainier (Mount Rainier Ntl. Park Mus.)

Remarks.—Shrew-moles are present on Destruction Island, a small island in the Pacific off the coast of Jefferson County. These moles are large, and are like gibbsii. It is thought, however, that this resemblance is due to convergent evolution rather than a once-continuous range with gibbsii. It is significant that a shrew (Sorex trowbridgii destructioni), the only other native land mammal on the island, differs from its mainland counterpart in much the same way as does Neurotrichus g. gibbsii from Neurotrichus g. minor.

Neurotrichus gibbsii minor [Dalquest] and [Burgner]

Neurotrichus gibbsii minor [Dalquest] and [Burgner], Murrelet, 22:12, April 30, 1941.

Type.—Obtained on the University of Washington Campus, Seattle, King County, Washington, by W. W. [Dalquest] on May 19, 1940; type in the Museum of Vertebrate Zoölogy.

Racial characters.—Size small; tail short; foreclaws light and weak as compared to those of gibbsii, with ventral surfaces curved.

Measurements.—Eighty-five specimens (males and females) from Seattle, King County, average: total length, 107.0; length of tail, 35.3; length of hind foot, 15.0.

Distribution.—The lowlands of western Washington. Marginal records are: Mt. Vernon ([Jackson], 1915: 97), Cottage Lake (W.W.D.) and Yacolt (M. V.Z.).

Genus Scapanus Pomel
Moles

Fig. 23. Coast mole (Scapanus orarius orarius) left and Townsend mole (Scapanus townsendii) right; Puyallup. Washington, May, 1914. (Fish and Wildlife Service photo by T. H. [Scheffer], No. B-18637.)

Moles are of stocky build and have cylindrical, rounded bodies. The eyes are tiny, nearly concealed in the fur. They have no external ears. The legs are short; the forefeet wide, spadelike, and armed with powerful claws. The fur is erect, not posteriorly directed. The color of the fur is deep bluish or brownish slate. The short, nearly naked tail is pale pink or whitish. Moles of this genus are found only along the Pacific Coast of North America from southern Canada south into Baja California.

Scapanus townsendii (Bachman)
Townsend mole

Scalops townsendii Bachman. Jour. Acad. Nat. Sci. Philadelphia, 8 (pt. 1):58, 1839.

Scapanus tow[n]sendii Pomel. Arch. Sci. Phys. Nat., Geneva, 9 (ser. 4):247, 1848.

Scapanus Townsendii True. Proc. U. S. Nat. Mus., 7 (1881):607, 1885.

Type.—Probably obtained at Fort Vancouver. Clark County. Washington, by J. K. [Townsend]. A cotype was obtained on May 9. 1835; type in Academy of Natural Sciences of Philadelphia.

Measurements.—Three males and 6 females from southwestern Washington average, respectively: total length 221, 214; length of tail 51, 46; hind foot 28.3, 26; weight 147, 117 grams.

Distribution.—The lowlands of western Washington. Marginal occurrences are: Sauk ([Jackson]. 1915: 61); Skykomish ([Jackson], 1915: 61) and Yacolt (M.V.Z.).

Remarks.—Scapanus townsendii occurs only in a narrow belt extending from southwestern British Columbia to northwestern California. It seems to prefer a generally damper habitat than the smaller-sized coast mole, although both species are sometimes found in the same locality. The larger mole is abundant in the meadows on the flood plains of rivers at low elevations, and on the glacial outwash prairies. It is often numerous in the fir forests, although its workings and mounds are less conspicuous there. The bodies of nine drowned individuals were found in a well by an old cabin in dense fir forest near Duvall, King County. Townsend moles occasionally occur in the Canadian Life-zone, as at Staircase on the north side of Lake Cushman in Mason County where workings were observed, but most records are from the Humid division of the Transition Life-zone.

The Townsend mole is mainly nocturnal. If ridges of its runways are crushed down, they usually remain so throughout the day and are rebuilt the following night. Only about ten per cent of the ridges that were crushed were rebuilt in the daytime, and most of these were repaired in the early morning. The species is almost completely subterranean. Some individuals are crushed on highways by cars, showing that these moles occasionally travel on the surface of the ground.

Townsend moles throw up numerous mounds, each usually containing about a cubic foot of earth. The mounds commonly are built just about as far apart as a man can step. The general direction as well as the twists and turns of a mole's burrow can usually be determined from the mounds. Townsend moles also construct ridges on the surface of the ground by pushing up sod in building a tunnel just below the grass roots. Smaller ridges are less commonly made by coast moles. More extensive tunnels, constructed deeper in the earth, serve as living quarters.

Fig. 24. Distribution of the Townsend mole, Scapanus townsendii, in Washington.

According to [Wight] (1928: 24), [Scheffer] (1922: 11) and [Moore] (1933: 39), the food of this large mole includes earthworms and ground-inhabiting insects, insect larvae, spiders, centipedes, flesh, and small amounts of soft vegetation. [Scheffer] (1922: 10) found that the large mole breeds in February and produces from two to four young at a litter, with an average of three.

Scapanus orarius
Coast mole

Description.—The coast mole is almost identical with the larger mole in form of body but is smaller. Head and body are about 5-1/4 and tail about 1-1/2 inches in length.

The coast mole occupies all of the territory inhabited by the Townsend mole and ranges slightly farther northward, southward and eastward. However it does not range east of the boundaries of the three Pacific Coast states or British Columbia.

The mounds and workings of the coast mole are smaller than those of the Townsend mole and consequently are less noticed. It seems less prone to make numerous mounds, a pace apart, than the larger mole, and burrows tend to extend deeper in the ground. Upthrust ridges are less commonly built by orarius than by townsendii.

Fig. 25. Coast mole (Scapanus orarius orarius). Freshly killed; Seattle, Washington, June 9, 1938. (Fish and Wildlife Service photo by Victor B. [Scheffer], No. 64.)

[Jackson] (1915: 62) mentions the possibility of ecologic differences between orarius and townsendii. There are some differences in habitat and habits. The coast mole seems to live deeper in the ground, prefers better drained soil, and is less colonial than the Townsend mole. These are average differences, however, and the two species commonly occur together. Another difference is that the larger mole rarely enters the dense deciduous woods, such as the brush-grown alder and dogwood jungles along the stream valleys. I have taken the coast mole in such localities, and often have found their workings there. The surface of a nearby meadow may be dotted with mounds of both species, but the larger mole seems not to enter ground that is thickly grown with brush. The coast mole ascends to greater altitudes in the Cascade Mountains than does the Townsend mole.

Like the larger mole the coast mole feeds principally on earthworms and insects ([Moore], 1933: 38). On September 29, 1939, in a ravine at Seattle, in two baited traps set six inches apart, a creeping mouse (Microtus oregoni) and a coast mole were found. The mouse had come to the bait and been caught. The mole had seemingly emerged from the ground through a tunnel a foot away and had been attracted to the body of the mouse. It had eaten an area a half inch in diameter and three-quarters of an inch deep into the body of the mouse just behind the shoulder, when in shifting its position it had become caught in the unsprung trap behind it. When found the mole lay dead with its nose inside the body of the mouse and its back broken. This is the only case known to me of a coast mole appearing voluntarily on the surface of the ground. Never have I found coast moles crushed on the highway; several Townsend moles so killed have been found.

Fig. 26. Distribution of the coast mole in Washington. A. Scapanus orarius orarius. B. Scapanus orarius yakimensis. C. Scapanus orarius schefferi.

The coast mole seems to breed very early in the spring. Males with swollen testes are found late in January. The young usually number four and are born in late March or early April. The breeding season seems to be the same as that of townsendii but the number of young to a litter may average slightly greater.

Scapanus orarius orarius True

Scapanus orarius True. Proc. U. S. Nat. Mus., 19:52, December 21, 1896.

Scapanus orarius orarius [Jackson], N. Amer. Fauna, 38:61, September 30, 1915.

Type.—Obtained at Shoalwater (= Willapa) Bay, Pacific County, Washington, by J. G. Cooper on August 30, 1855; type in United States National Museum.

Racial Characters.—Color dark bluish; frontal region of skull not inflated.

Measurements.—Eight males and two females from Seattle, King County, average, respectively: total length 159, 155; length of tail 33, 31; hind foot 20.7, 20.5; weight 58.5, 55.8.

Distribution.—Western Washington. Marginal occurrences are: Skykomish (B.S.C.), Merritt (B.S.C.), Wenatchee (B.S.C.), Lester ([Jackson], 1915: 64) and Yacolt (M.V.Z.).

Scapanus orarius yakimensis [Dalquest] and [Scheffer]

Scapanus orarius yakimensis [Dalquest] and [Scheffer], Murrelet, 25:27, September 19, 1944.

Type.—Obtained 3/4 mile north of Union Gap, Yakima County, Washington, by J. A. [Gray], Jr., on July 3, 1941; type in Museum of Vertebrate Zoölogy.

Racial Characters.—Color pale, grayish; skull narrow with inflated frontal region.

Measurements.—Six specimens (males and females) from Selah, Yakima County, average: total length 164; length of tail 37; length of hind foot 21.5. The type specimen weighed 58 grams.

Distribution.—The Yakima Valley area; recorded from the type locality northwestward to Easton (B.S.C.).

Scapanus orarius schefferi [Jackson]

Scapanus orarius schefferi [Jackson], N. Amer. Fauna, 38:63, September 30, 1915.

Type.—Obtained at Walla Walla, Walla Walla County, Washington, by T. H. [Scheffer] on August 8, 1914; type in United States National Museum.

Racial Characters.—Large size; pale color; large, wide skull with inflated frontal area.

Measurements.—Six topotypes average: total length 159; length of tail 35; hind foot 21.5.

Distribution.—Southeastern Washington; recorded from Fort Walla Walla ([Jackson], 1915: 64), Walla Walla ([Jackson], 1915: 64) and Dayton (M.V.Z.).

Genus Sorex Linnaeus
Long-tailed shrews

Shrews have tiny eyes, almost concealed in the fur. The body is slim; the nose elongate and pointed. The legs are short and the feet small and weak. The fur is short but soft and posteriorly directed. The cinereous shrew, for example, is about 4 inches in length, of which the tail comprises 1-3/4 inches. The upper parts are dark grayish brown and the underparts dull gray.

Shrews of the genus Sorex are cosmopolitan in distribution. In North America they range from the arctic south to Central America. Three subgenera are recognized by [Jackson] (1928: 27), all three of which are represented in the state of Washington. The twelve subspecies present occupy numerous habitats, and their ranges include almost all of the state.

[Jackson] pointed out (1928: 1) that "No other group of American mammals having a wide distribution, and in many localities an abundance of individuals, is so little known to the nonprofessional mammalogist as the long-tailed shrews." In Washington, especially in the coastal area of western Washington, shrews are widespread and abundant in many habitats. In some places they are the most common mammal present. In spite of this their presence is often unsuspected by persons that are otherwise alert to the animal life around them. This is even more surprising when one takes into account the facts that long-tailed shrews are diurnal as well as nocturnal and are less apt to detect the presence of man than are most other species of mammals.

An important factor making long-tailed shrews inconspicuous is their small size, and contributing factors include their rapid movements and dull colors. On several occasions the writer, after seeing a long-tailed shrew vanish soundlessly under a log or into a patch of dead leaves, was left wondering if one actually had been seen or if instead his imagination had conjured up an animal from a dust mote or wind-blown leaf.

The environment of the long-tailed shrews, except for the water shrews, is the zone at the very surface of the earth, just beneath the layer of moss, grass, dead leaves, and decaying vegetation. The removal of the covering vegetative layer reveals a maze of tiny tunnels, the branchings and complexities of which are infinite. Tiny traps baited with oats or meat and set in these runways catch the long-tailed shrews that inhabit them.

The food of long-tailed shrews is varied. It is principally soft-bodied insects, insect pupae, and earthworms. At times a considerable quantity of soft vegetation and some seeds are eaten. Recent studies ([Moore], 1940: 1942) have shown that by destroying seeds some shrews may adversely affect the reforestation of some coniferous trees. Shrews readily eat meat, and often destroy the small mammals, including other shrews, taken in the mammal collector's traps.

[Hamilton] (1940: 485) found that in one species of long-tailed shrew in the United States individuals rarely lived more than one year. This seems not to be true of at least some of the species found in Washington.

Parasites, internal or external, are not commonly found on long-tailed shrews. They are regularly eaten by owls and snakes, but most carnivorous mammals, though they readily kill them, rarely eat them.

Sorex cinereus Kerr
Cinereous shrew

The cinereous shrew ranges over most of Alaska, Canada and the northern half of the United States. A number of subspecies have been described, of which two have been reported from Washington. The cinereous shrew is of medium size and difficult to distinguish from the dusky and wandering shrews, especially in eastern Washington, without studying the skulls. In cinereus the fourth unicuspid tooth is smaller than the third; in vagrans and obscurus it is larger. The relatively narrow rostrum of cinereus also serves to separate it from the other two species.

The cinereous shrew seems to be less restricted to the vicinity of streams and marshes than Sorex vagrans, resembling Sorex obscurus and Sorex trowbridgii in this respect. In Washington it seems to be rare and has not been taken by the writer. Published records for Sorex c. cinereus indicate that this race is, in Washington, confined to mountainous areas. The coastal race, streatori, seems to be confined to the humid area.

Sorex cinereus cinereus Kerr

Sorex arcticus cinereus Kerr. Anim. Kingd., p. 206, 1792.

Sorex cinereus cinereus Jackson. Jour. Mamm., 6: 56, February 9, 1925.

Type.—None. Name based on the account of a shrew seen at Fort Severn, Canada, by J. R. Forster in 1772.

Racial characters.—Small size and pale color.

Measurements.—Seven males and 8 females from Indian Point Lake, British Columbia, average, respectively: total length 99, 95; length of tail 43.5, 42.2; hind foot 12.7, 12.3.

Distribution.—Northeastern Washington (Metaline and Loon Lake, [Jackson], 1928: 49) and the Cascades from Whatcom Pass ([Jackson], 1928: 55) southward to Conrad Meadows ([Jackson], 1928: 49). There is a specimen in the collection of the California Academy of Sciences, from Mt. Rainier.

Remarks.—This is the most wide-ranging subspecies of shrew, being recorded from Alaska, 10 Canadian provinces and 26 states ([Jackson], 1928: 46-50). In the more northern and eastern parts of its range it is sometimes the commonest shrew.

Fig. 27. Distribution of the cinereous shrew in Washington. A. Sorex cinereus cinereus. B. Sorex cinereus streatori.

Sorex cinereus streatori [Merriam]

Sorex personatus streatori [Merriam]. N. Amer. Fauna, 10:62, December 31. 1895.

Sorex cinereus streatori [Jackson]. Jour. Mamm., 6:56. February 9, 1925.

Type.—Obtained at Yakutat, Alaska, by C. P. Streator on July 9, 1895; type in the United States National Museum.

Racial characters.—Larger and darker than Sorex cinereus cinereus.

Measurements.—Five females from Alta Lake, British Columbia, average: total length 103; length of tail 45; hind foot 12.5.

Distribution.—The western part of the northern Cascades (Glacier, [Jackson], 1928: 55) and the Olympic Peninsula (Neah Bay south to Cedarville, [Jackson], 1928: 55).

Remarks.—This shrew seems to occupy the same range as Sorex obscurus setosus but is rare where obscurus is common.

Sorex merriami merriami Dobson
[Merriam] shrew

Sorex merriami Dobson. Monogr. Insectivora, pt. 3, fasc. 1, pl. 23, fig. 6, May, 1890.

Sorex merriami merriami Benson and Bond. Jour. Mamm., 20: 348, August 14, 1939.

Type.—Obtained on Little Bighorn River, about a mile and a half above Fort Custer, Crow Indian Reservation, Montana, by Charles E. Bendire on December 26, 1884; type in United States National Museum.

Measurements.—Of type: total length 90; length of tail 35; hind foot 11.5 (after [Jackson], 1928: 80).

Distribution.—A single specimen of this rare shrew is known from Washington. [Jackson] (1928: 81) states that it "was collected by George G. Cantwell, November 18, 1919, at the entrance to an old badger digging on top of a 'high bunch grass hill' at Starbuck (altitude 645 feet), Columbia County, Wash."

Description.—Similar to Sorex cinereus but upper parts pale grayish and underparts white.

The [Merriam] shrew has been recorded from but a few localities in the western United States. It is one of the rarest of the small mammals known to occur in North America. All the known specimens have been found in desert areas.

Sorex trowbridgii [Baird]
Trowbridge shrew

Description.—The Trowbridge shrew closely resembles the cinereous shrew in body form but possesses a longer tail. The head and body of adults measure about 2-1/4 inches and the tail about 2 inches. The Trowbridge shrew may be separated from all other small shrews that occur in Washington by its dark bluish upper parts and bluish or slaty underparts. The tail is distinctly bicolor.

Trowbridge shrews occur from southern British Columbia south to central California. Their distribution, to the south, is more extensive than that of many members of the Pacific Coastal Fauna. They are forest animals, ranging widely over the dry ground beneath the fir forest, where they are usually the only shrews present. They are abundant in ravines and in some swampy woods when other shrews are absent, but they avoid open meadows or marshes. Vertically, they occur from the humid division of the Transition Life-zone to the Hudsonian Life-zone.

These little shrews do not live well in captivity and I have learned relatively little concerning their habits from live specimens. They seem to be slower-moving and less aggressive than the wandering shrew. Population studies showed that the Trowbridge shrew is unable to compete with the wandering shrew in ravine habitats ([Dalquest], 1941A: 173). The principal food of the Trowbridge shrew includes soft-bodied insects and insect pupae.

Fig. 28. Distribution of the [Merriam] and Trowbridge shrews in Washington. A. Sorex merriami merriami. B. Sorex trowbridgii trowbridgii. C. Sorex trowbridgii destructioni.

[Moore] (1942) has shown that shrews eat the seeds of the Douglas fir and may be a serious check on the reproduction of this important tree. The Trowbridge shrew is the most abundant shrew in the fir forests and probably constitutes the principal shrew that might be classed as a pest.

A specimen containing 4 embryos was taken near Shelton, Mason County, on April 23, 1937. Males with enlarged, greenish testes were taken in April of 1938, 1939 and 1940. Specimens obtained in other months showed no indications of breeding.

Sorex trowbridgii trowbridgii [Baird]

Sorex trowbridgii [Baird], Rept. Pacific R. R. Survey, 8 (pt. 1):13, 1857.

Type.—Two cotypes were obtained at Astoria, Clatsop County, Oregon. The skin of one (the lectotype) was entered in the U. S. National Museum catalogue in July, 1855, and the skull in January, 1857. The other was obtained by J. Wayne on July 10, 1855.

Racial characters.—Small size and narrow skull.

Measurements.—The average measurements of 38 adults from King County, Washington, are: total length 115.3; length of tail 54.4; hind foot 13.4.

Distribution.—Forested areas from the Pacific Coast eastward through the Cascades to Stehekin ([Jackson], 1928: 96), 2 mi. S. Blewitt Pass ([Jackson], 1928: 96) and Satus Pass (M.V.Z.).

Sorex trowbridgii destructioni [Scheffer] and [Dalquest]

Sorex trowbridgii destructioni [Scheffer] and [Dalquest], Jour. Mamm., 23:334, August 13, 1942.

Type.—Obtained on Destruction Island, Jefferson County, Washington, by V. B. [Scheffer] on April 22, 1941; type in United States National Museum.

Racial characters.—Large size and wide skull.

Measurements.—Thirty topotypes average: total length 122.5; length of tail 56.7; hind foot 14.3; weight 7.5 grams.

Distribution.—Known only from Destruction Island, 35 acres in area, lying 4 miles off the Washington Coast.

Sorex vagrans [Baird]
Wandering shrew

Description.—This species closely resembles the cinereous shrew in body form. Its head and body measure about 2-1/4 inches; the tail slightly less than 2 inches. In summer the upper parts are reddish brown and the underparts gray tinged with brownish. In winter the upper parts are more dusky.

Several races of the wandering shrew range over western North America from southwestern British Columbia south to southern Mexico. Two races occur in the state of Washington.

Marshy areas and damp places are the habitat of the wandering shrew. Cattail and tule marshes, sphagnum bogs, and meadows are favored. They frequent streams through forests but rarely are taken in places away from water. On some of the San Juan Islands, wandering shrews were found along the beaches where they were feeding on the amphipods that live in the dead seaweed and litter at the high tide line. In a favorable habitat, wandering shrews may be the most abundant mammal present. Specimens are occasionally taken in 90 per cent or more of a mammal collector's traps.

The preference of the wandering shrew for damp areas makes it more or less independent of life-zones, for marshy areas, whether in Transition, Canadian, or Upper Sonoran life-zones, present comparable ecological conditions.

Broadbrooks (1939: 65) found that captives taken at Seattle ate rolled oats, apple, fresh or cooked meat, sow bugs, centipedes, earthworms, frogs (Hyla regilla), a salamander (Plethodon vehiculum), and small, black slugs (Arean arean). Wandering shrews proved incapable of destroying snails (Helisoma occidentalis) and large slugs. The captive shrews kept by Broadbrooks ate an average of 1.3 times their own weight in food each day.

Fig. 29. Distribution of the wandering shrew in Washington. A. Sorex vagrans vagrans. B. Sorex vagrans monticola.

The wandering shrew changes from winter to summer pelage in a few days, seemingly in the second week of October ([Dalquest], 1944: 147). The spring molt occurs rapidly but perhaps at a less regular date. Rarely a midsummer molt occurs.

The earliest evidence of breeding in a wandering shrew was discovered on January 27, 1937. Most adult females taken in February, March, April and May were pregnant. Embryos were less often found in summer and fall, but one pregnant female was taken in November. Embryos varied in number from 3 to 8 with an average of six.

Sorex vagrans vagrans [Baird]

Sorex vagrans [Baird], Rept. Pacific R. R. Survey, 8 (pt. 1):15, 1857.

Sorex suckleyi [Baird], Rept. Pacific R. R. Survey, 8 (pt. 1):18, 1857 (type from Steilacoom Pierce County, Washington).

Type.—Obtained at Willapa Bay [Shoalwater Bay], Pacific County, Washington, by J. G. Cooper; entered in U. S. Nat. Mus. catalogue on October 23, 1856.

Racial characters.—Dark color.

Measurements.—Twenty-five males and 25 females from Seattle, King County, average, respectively: total length 110.5, 107; length of tail 44.6, 45; hind foot 12.4, 12.4.

Distribution.—This is the common marsh shrew of western Washington and occurs from the Pacific Ocean east to the Cascades at Lake Keechelus (W.S.M.) and 15 mi. NW White Salmon ([Jackson], 1928: 106).

Sorex vagrans monticola [Merriam]

Sorex monticolus [Merriam], N. Amer. Fauna, 3:43, September 11, 1896.

Sorex vagrans monticola [Merriam], N. Amer. Fauna, 10:69, December 31, 1895.

Type.—Obtained on San Francisco Mountain, 1150 ft. altitude, Coconino County, Arizona, by C. H. [Merriam] and V. [Bailey] on August 28, 1889; type in United States National Museum.

Racial characters.—Pale color.

Measurements.—Five males and 5 females from Selah, Yakima County, average, respectively: total length 100, 98.4; length of tail 40.6, 39.2; hind foot 12.2, 12.

Distribution.—Eastern Washington. The range of this shrew extends west to Bauerman Ridge ([Jackson], 1928: 113), Merritt (W.W.D.) and Maryhill (M.V.Z.).

Remarks.—A series of shrews from Moses Lake, Grant County, differs from monticola in larger size and darker color. They agree rather closely with Sorex r. amoenus from California and Nevada. Because they are isolated from that subspecies it seems best to consider them a microgeographic race referable to monticola.

Sorex obscurus [Merriam]
Dusky shrew

Description.—The dusky shrew is similar in form of body to the cinereous shrew. The length of head and body is about 2-1/4 inches. The tail is about 2-1/2 inches. The upper parts are rusty or reddish brown. The underparts are brownish gray. The dusky shrew differs from the wandering shrew in possessing a slightly longer body and longer tail, but in eastern Washington the two species are almost indistinguishable.

Dusky shrews range from northern Alaska to southern New Mexico, and from the Rocky Mountains to the Pacific Ocean. Thirteen subspecies are recognized by [Jackson] (1928: 115), of which two occur in Washington.

Records of the dusky shrew are not available from the arid subdivision of the Transition or the Upper Sonoran life-zones. It occurs sparingly in the humid subdivision of the Transition and is common in the Canadian and Hudsonian life-zones.

The habitat of the dusky shrew is varied. Near Seattle, King County, several specimens were trapped in marshes where Sorex vagrans was abundant. Near Stevens Pass, King County, two were taken in a marsh; two others were trapped in a dry, coniferous forest; one was taken in a small bed of heather on a barren mountain top; and another was found dead in a pan of pancake batter in camp. Two specimens were trapped along a small stream at Dewey Lake, Mt. Rainier, Yakima County. Four specimens were caught in traps set in a talus slope on a dry hillside at the North Fork of the Quinault River, Jefferson County. Three others were trapped in dense, rain-forest thickets along the ocean at La Push, Jefferson County. These records indicate that the dusky shrew has a wider environmental range than other Washington shrews. Despite this wide range of tolerance the dusky shrew is common only locally, except in the Hudsonian Life-zone.

Little is known of the habits of dusky shrews but they seem to be as diurnal as they are nocturnal. At Wolf Bar, North Fork of the Quinault River, Jefferson County, a dusky shrew was seen on the packed-earth floor of an old trapper's cabin. A hat was carefully dropped over the live animal but, when the hat was lifted, the shrew was found dead. In an old cabin at Stevens Pass, King County, a dusky shrew was found dead one morning in a pan of flapjack batter prepared the evening before. As this pan was on a table about three feet from the floor, the shrew must have climbed to the table by way of the rough cabin wall, but how the animal managed to scale the side of the pan is a mystery.

[Slipp] (1942: 211) discovered the nest of a dusky shrew between Round Pass and Lake George, 4200 feet elevation, in Mt. Rainier National Park, on July 25, 1937. The nest was in a rotten fir log 20 inches in diameter. The nest, a ball of dry grass the size of a man's fist, had no central cavity or passages, the occupants "merely pushed through wherever they wished." Seven young shrews were found in and near the nest. Though the eyes of the young were still closed, they were able to creep about and squeal.

A specimen obtained 5 miles west-southwest of Guler, Skamania County, contained 4 embryos on July 10, 1939.

Fig. 30. Distribution of the dusky shrew in Washington. A. Sorex obscurus obscurus. B. Sorex obscurus setosus.

Sorex obscurus obscurus [Merriam]

Sorex vagrans similis [Merriam], N. Amer. Fauna, 5: 34, July 30, 1891 (not of Hensel, 1855).

Sorex obscurus [Merriam], N. Amer. Fauna, 10: 72, December 31, 1895 (substitute for similis [Merriam]).

Type.—Obtained on Timber Creek, 8,200 ft., Lemhi Mountains, Lemhi County, Idaho, by V. [Bailey] and B. H. Dutcher on August 26, 1890; type in United States National Museum.

Racial characters.—Tail relatively short, color pale.

Measurements.—Thirteen males and 10 females from Indian-point Lake, British Columbia, average, respectively: total length 105, 107; length of tail 45, 46; hind foot 13.3, 13.3.

Distribution.—Northeastern Washington west, according to [Jackson] (1928: 122), to Pasayten River, Stehekin and Wenatchee. Because specimens from Tye, King County, and Mt. Stuart, Easton and Lake Keechelus are clearly referable to S. o. setosus, the specimens recorded by [Jackson] (1928: 122), from Easton and Signal Peak, are mapped in the range of setosus.

Sorex obscurus setosus [Elliot]

Sorex setosus [Elliot], Field Columb. Mus. Publ. 32. zoöl, ser., 1:274. March, 1899.

Sorex obscurus setosus [Jackson], Proc. Biol. Soc. Washington. 31:127. November 29, 1918.

Sorex obscurus bairdi [Jackson], N. Amer. Fauna, 51:140. July 24, 1928.

Type.—Obtained at Happy Lake, Clallam County, Washington, by D. G. [Elliot] on August 18, 1898; type in Field Museum of Natural History.

Racial characters.—Tail long, color dark.

Measurements.—Twelve males and 17 females from southwestern Washington average, respectively: total length 118, 119; length of tail 53, 53; hind foot 13.8, 13.7; weight 6.6, 5.2 grams.

Distribution.—Western Washington, east through the Cascades to Barron ([Jackson], 1928: 137), Cascade River ([Jackson] 1928: 137) and Satus Pass (W. W. D.).

Sorex palustris navigator ([Baird])
Mountain water shrew

Fig. 31. Distribution of the mountain water shrew. Sorex palustris navigator, in Washington.

Neosorex navigator [Baird], Rept. Pacific R. R. Survey, 8 (pt. I): 11, 1857.

Sorex (Neosorex) palustris navigator [Merriam], N. Amer. Fauna, 10:92, December 31, 1895.

Sorex palustris navigator Stephens, California Mammals, p. 254, June, 1906.

Type.—Obtained at head of Yakima River, Kittitas County, Washington, by J. G. Cooper on August 31, 1853; type in United States National Museum.

Measurements.—Two males and 4 females from Washington average, respectively: total length 150, 150; length of tail 70, 74; hind foot 18.5, 20; weight?, 11.0 grams.

Distribution.—Mountainous areas of entire state, including the Olympic Mountains, from Elwah ([Jackson], 1928: 188) south to Quinault River ([Jackson], 1928: 189); the Cascades from Tomyhoi Lake (W. W. D.) south to 15 mi. N. Carson ([Jackson], 1928: 189); northeastern Washington from Shovel Creek (W. W. D.) south to Gifford ([Jackson], 1928: 189); the Blue Mountains at Godman Springs (M. V. Z.) and Hompeg Falls (M. V. Z.).

Description.—In general form of body the mountain water shrew resembles the cinereous shrew but is perhaps more stocky. It is a large shrew, nearly as large as a house mouse. The head and body measure about 3 inches; the tail also is about 3 inches long. The fur is exceedingly soft. The upper parts are blackish in color, lightly frosted with paler hairs. The underparts, from throat to vent, are whitish tinged with gray or brown. The stiff, curved fringe of bristles on the outer part of the hind foot serves as an aid in swimming.

Mountain water shrews range over much of Canada and in mountainous areas of the western United States extend south to Arizona. The subspecies found in Washington ranges over all of the western United States.

The mountain water shrew is primarily a mammal of the Hudsonian and Canadian life-zones. It sometimes descends to the Transition Life-zone along clear, cold streams where conditions are similar to those in the Canadian Life-zone.

The favored habitats of the mountain water shrew are the clear, cold streams of the alpine cirques and gushing streams on the mountain sides. In the pools and waterfalls, and among the rocks and mosses that border them, the larvae of aquatic insects, upon which the mountain water shrew feeds, are abundant. [Svihla] (1934: 45) observed that the fur of a swimming water shrew gathered air bubbles and "it had difficulty in forcing its way down to the bottom [of an aquarium]. On reaching the bottom it literally stood on its long flexible nose which was thrust into the sand and debris, searching for food, its feet kicking rapidly in order to maintain this position. A change in direction was brought about by a twist of the body. To come to the surface again it merely stopped kicking and immediately rose like a cork." The buoyancy of the water shrew allows it to float in the water, like a duck. [Jackson] (1928: 9) observed a water shrew run across the surface of a small pool. Near Stevens Pass a water shrew dashed from under a stone and ran, did not swim, across the surface of a small, deep pool to escape in a burrow on the other side. According to [Jackson], an air bubble held in each foot supports the shrew on the surface of the water. A mountain water shrew observed at Shovel Creek, Ferry County, was as agile on land as any other species of shrew. In summary, water shrews are able to swim, dive, float like a duck, and walk on the surface of the water as well as walk on land.

The food of the mountain water shrew includes snails, leeches, and the larvae of aquatic insects. Mice caught in traps are sometimes eaten by water shrews. [Svihla] (loc. cit.) found a captive water shrew unable to capture pollywogs and minnows kept in the same aquarium.

Sorex bendirii ([Merriam])
Bendire water shrew

Description.—The Bendire water shrew is similar in form of body to the cinereous shrew but possesses a more stocky body which, with the head, measures about 3-1/2 inches long; the tail is about 2-3/4 inches long. The Bendire water shrew closely resembles also the mountain water shrew but has a longer body and shorter tail. The upper parts are blackish in color, not lightly frosted with gray hairs. The hind feet lack the fringe of stiff, curved bristles characteristic of the mountain water shrew. The underparts are black in the race S. b. bendirii. In the race albiventer the throat is blackish but the abdomen is pale gray tinged with brownish.

Fig. 32. Distribution of the Bendire water shrew and the pigmy shrew in Washington. A. Sorex bendirii bendirii. B. Sorex bendirii albiventer. C. Microsorex hoyi washingtoni.

Bendire water shrews are restricted to the Pacific Coast of North America from southern British Columbia to northern California. Generally they are found at elevations lower than are mountain water shrews. They are typically mammals of the humid division of the Transition Life-zone but often occur in the Canadian Life-zone. They occupy marshes, swamps, damp ravines, and the banks of slow-moving streams. Little is known of their habits, except what has been deduced from the circumstances of their capture. They seem less aquatic than the mountain water shrew. Near Jackson Guard Station on the Hoh River, Jefferson County, one was taken by setting traps on dense beds of water cress that floated in a slow-moving stream. The animal must have swum or walked on the surface of the mat of vegetation. Near Paradise Lake, King County, several were caught in a deep, dark, red cedar swamp. One was caught in a marsh nearby. Nothing is known of the food habits of the Bendire water shrew.

Sorex bendirii bendirii ([Merriam])

Atophyrax bendirii [Merriam], Trans. Linn. Soc. New York, 2:217, August 28, 1884.

Atophyrax Bendirei True, Proc. U. S. Nat. Mus., 7 (1884):606, 1885.

Sorex bendirii Dobson, Monog. Insectivora, part 3, fasc. 1, pl. 23, 1890.

Neosorex bendirii bendirii [Miller], U. S. Nat. Mus. Bull., 79:22, December 31, 1912.

Type.—Obtained approximately 1 mile from Williamson River, 18 miles southeast of Fort Klamath, Klamath County, Oregon, by C. C. Bendire on August 1, 1882; type in United States National Museum.

Racial characters.—Underparts everywhere sooty black.

Measurements.—Ten males and 10 females from southwestern Washington average, respectively: total length 163.9, 161.0; length of tail 71.0, 72.6; hind foot 20.5, 20.3; weight 16.8, 14.5 grams.

Distribution.—The southern Cascades and the lowlands of western Washington, exclusive of the Olympic Peninsula. Marginal localities on the west include Mt. Vernon ([Jackson], 1928: 196), Bothell (W.S.M.), Renton (M.V.Z.), Puyallup (W.W.D.), Steilacoom ([Jackson], 1928: 196) and Oakville ([Jackson], 1928: 196).

Sorex bendirii albiventer [Merriam]

Sorex (Atophyrax) bendirii albiventer [Merriam], N. Amer. Fauna, 10:97, December 31, 1895.

Neosorex bendirii albiventer [Miller], U. S. Nat. Mus. Bull., 79:22, December 31, 1912.

Sorex bendirii albiventer [Jackson], N. Amer. Fauna, 51:198, July 24, 1928.

Type.—Obtained at Lake Cushman, Mason County, Washington, by C. P. Streator on July 7, 1894; type in United States National Museum.

Racial characters.—Area on abdomen whitish.

Measurements.—A male from near the type locality measures: total length 167; length of tail 69; hind foot 22. One from Potlatch, Mason County, measures 167; 69; 22.

Distribution.—The Olympic Peninsula of Washington. Marginal localities on the south are: Potlatch (M.V.Z.) and Lake Quinault ([Jackson], 1928: 199).

Microsorex hoyi washingtoni [Jackson]
Pigmy shrew

Microsorex hoyi washingtoni [Jackson], Proc. Biol. Soc. Washington, 38:125, November 13, 1925.

Type.—Obtained at Loon Lake, Stevens County, Washington, by V. [Bailey] on September 26, 1897; type in United States National Museum.

Measurements.—Of type: total length 89; length of tail 27; hind foot 9.

Distribution.—In Washington, known only from the type specimen which was "found dead in a trail in dry pine woods" ([Jackson], 1928: 4).

Description.—The pigmy shrew is similar in form of body to the cinereous shrew but smaller. The head and body are about 1-3/4 inches in length; the tail is about 1 inch long. The upper parts are reddish brown and the underparts are gray.

These tiny mammals range widely across central Canada and northern United States from the Atlantic nearly to the Pacific, and north to central Alaska. A single species is known, one race of which occurs in Washington. The subspecies is known from but two specimens: the type and an individual from Montana ([Koford], 1938: 372.)

Genus Myotis Kaup
Mouse-eared bats

Description.—The genus Myotis may be separated from all other bats that occur in Washington by the presence of 38 teeth (dental formula i. 2-2/3-3, c. 1-1/1-1, p. 3-3/3-3, m. 3-3/3-3 = 38). Their small size separates them from all other genera save Pipistrellus, from which Myotis may be distinguished by the straight, rather than hooked, anterior border of the tragus. Species of Myotis found in Washington vary considerably in size, but all are less than 100 mm. in total length. The upper parts are various shades of brown in color. The ears, when laid forward, always extend to the nostrils or beyond.

This genus is one of the most widely ranging groups of Recent mammals. It occurs on all continents, including Australia and many of the larger islands. Of the 19 American species recognized by [Miller] and [Allen] (1928), eight occur in the state of Washington. They are low-flying forms and as a rule appear relatively late in the evening. Their flight is rapid and erratic. They often hunt over the surfaces of streams, pools, and lakes. Some kinds hunt in the shade of forest trees and these are especially difficult to collect. Others hunt the brushy canyons and coulees of the desert areas of eastern Washington.

[Grinnell] (1918: 241-242) points out that, although bats are not subject to isolation by topographic barriers, as most wingless mammals are, they may be restricted by ecologic barriers in the same way as are other small mammals. This is particularly true of Myotis in Washington. Of the eight species in the state, five are represented by one subspecies west of the Cascade Mountains and another, paler subspecies in the more arid country east of the Cascades.

The mobility of bats makes it difficult to determine their origin and migrational history. Five of the Myotis found in Washington seem to belong to the Pacific Coastal Fauna, and to have been isolated south of the last continental glacier. Complete isolation is unlikely as these species occur in the Cascade Mountains as well as in the Pacific Coastal Faunal Area, and three occur also in the Blue Mountains of southeastern Washington. The differentiation of the Coastal type of Myotis may have come about through habitat selection, of the type discussed by [Miller] (1942: 25). One western Washington Myotis (M. keenii) seems to belong to a northern fauna, and to have extended its range south to Washington. All seven species of the desert-living Myotis found in eastern Washington have subspecies which seem to have been derived from the Great Basin Faunal Area.

Myotis lucifugus (Le Conte)
Big myotis

Myotis lucifugus is represented by two geographic races in Washington. The species ranges across Canada and the United States, from the Atlantic to the Pacific and from the northern limit of tree growth to southern Mexico.

Fig. 33. Distribution of the big myotis in Washington. A. Myotis lucifugus alascensis. B. Myotis lucifugus carissima.

It usually proves rather difficult to separate Myotis lucifugus, on the basis of external features, from other species with which it may occur. Its large foot (9-10 mm.), short ear (when laid forward not extending past nose) and the absence of a keel on the calcar separate it from all species except Myotis yumanensis. From the latter species, lucifugus may be distinguished by the gradually rather than abruptly rising forehead, as seen in cleaned skulls, and by more shiny, metallic color of fur.

Little is known of the habits of this bat in Washington. It usually appears after dusk, and most specimens are shot over ponds or lakes, where the reflection of light from the sky on the water allows the hunter enough light to sight a gun. A few specimens were collected in deep forests. Its flight and feeding habits are not known to differ from those of other species with which it was associated, except at the south end of Lake Chelan, Chelan County, where two individuals were shot as they hovered near the tops of pine trees and seemed to be picking insects from the branches. I have never found this bat in its daytime retreat.

A specimen taken at Sportman's Lake, San Juan County, held one embryo on June 26, 1938.

Myotis lucifugus carissima Thomas

Myotis (Leuconoë) carissima Thomas, Ann. and Mag. Nat. Hist., 13 (ser. 7): 383, May, 1904.

Myotis lucifugus carissima Cary, N. Amer. Fauna, 42:43, October 3, 1917.

Type.—Obtained at Yellowstone Lake, Yellowstone National Park, Wyoming by J. Darling in September, 1903; type in British Museum.

Racial characters.—Color pale, rather "brassy" in tone; distal border of interfemoral membrane paler than proximal part.

Measurements.—Four specimens from eastern Washington average: total length 77; length of tail 33; hind foot 11; ear 13; height of tragus 7.3.

Distribution.—East of the eastern base of the Cascade Mountains, save for the Blue Mountains of southeastern Washington. Western records are Stehekin ([Miller] and [Allen], 1928: 52) and Vantage (W. W. D.)

Myotis lucifugus alascensis [Miller]

Myotis lucifugus alascensis [Miller], N. Amer. Fauna, 13:63, October 16, 1897.

Vespertilio gryphus lucifugus [Allen], U. S. Nat. Mus. Bull., 43:78, March 14, 1894 (part specimens from Washington).

Type.—Obtained at Sitka, Alaska, by C. P. Streator on August 5, 1895; type in United States National Museum.

Racial characters.—Color dark, almost bronze; wing and tail membranes uniformly dark in color.

Measurements.—Five specimens from San Juan County, Washington, average: total length 80.9; length of tail 32.1; hind foot 12; ear 12; height of tragus 7; weight 5.4 grams.

Distribution.—From the eastern base of the Cascade Mountains west of the Pacific, and the Blue Mountains of southeastern Washington. Marginal occurrences listed by [Miller] and [Allen] (1928:49) are Chilliwack River, Lake Wenatchee, and Lyle.

Myotis yumanensis (H. [Allen])
Yuma myotis

Description.—The present species closely resembles Myotis lucifugus and specimens in worn pelage can not be distinguished from that species unless the cleaned skulls are examined. In fresh pelage, yumanensis is duller than lucifugus.

Myotis yumanensis ranges from southern British Columbia to central Mexico west of the Mississippi River. Four races are recognized by [Miller] and [Allen] (1928: 62).

Fig. 34. Distribution of the Yuma myotis in Washington. A. Myotis yumanensis saturatus. B. Myotis yumanensis sociabilis.

The habits of Myotis yumanensis and Myotis lucifugus appear to be the same. In Washington the two species are commonly found together. In western Washington, Myotis yumanensis seems to be more common than Myotis lucifugus.

In the San Juan Islands a yumanensis was found hiding in the attic of an old cabin on Blakeley Island. A specimen of long-eared bat was taken at the same place. Another Yuma myotis was caught behind a door of a mill on Blakeley Island ([Dalquest], 1940: 4).

This species shares with Myotis californicus the habit of apparently drinking salt water.

A specimen obtained at Sportsmans Lake, San Juan County, held one embryo on June 27, 1938. One from Peavine Pass, Blakeley Island, San Juan County, held one embryo on June 22, 1939.

Myotis yumanensis sociabilis H. W. [Grinnell]

Myotis yumanensis sociabilis H. W. [Grinnell], Univ. California Publ. Zoöl., 12:318, December 4, 1914.

Type.—Obtained at old Fort Tejon, Kern County, California, by J. [Grinnell] on July 23, 1904; type in Museum of Vertebrate Zoölogy.

Racial character.—Color pale.

Measurements.—Two males and 2 females from Selah, Yakima County, average: total length 78; length of tail 36; hind foot 10; ear 14; height of tragus 7.

Distribution.—Eastern Washington generally. Marginal records on the west are: Stehekin ([Miller] and [Allen], 1928: 69), and Selah (W.W.D.).

Fig. 35. Distribution of the fringe-tailed myotis and the Keen myotis in Washington. A. Myotis thysanodes thysanodes. B. Myotis keenii keenii.

Myotis yumanensis saturatus [Miller]

Myotis yumanensis saturatus [Miller], N. Amer. Fauna, 13:68, October 16, 1897.

Type.—Obtained at Hamilton, Skagit County, Washington, by T. S. Palmer on September 13, 1889; type in United States National Museum.

Racial character.—Color dark.

Measurements.—Eighteen adults of both sexes from San Juan County, Washington, average: Total length 78.2; length of tail 34.4; hind foot 10.1; ear 15; height of tragus 7.4; weight 5.9 grams.

Distribution.—From the eastern base of the Cascade Mountains to the Pacific. This is the commonest Myotis found in western Washington. Marginal localities are: Hamilton ([Miller] and [Allen], 1928: 71), and Goldendale ([Miller] and [Allen], 1928: 71).

Myotis keenii keenii ([Merriam])
Keen myotis

Vespertilio subulatus keenii [Merriam], Amer. Nat., 29:860, September, 1895.

Myotis subulatus keenii [Miller], N. Amer. Fauna, 13:77, October 16, 1897.

Myotis keenii keenii [Miller] and [Allen], U. S. Nat. Mus. Bull., 144:104, May 25, 1928.

Type.—Obtained at Masset, Graham Island, Queen Charlotte Islands, British Columbia, by J. H. Keen in 1894; type in United States National Museum.

Measurements.—[Miller] and [Allen] (1928: 109) list the measurements of a male from Sol Duc Hot Springs, Clallam County, and a specimen of unknown sex from Lake Cushman, Jefferson County, as, respectively: total length 89, 87; length of tail 34, 36; hind foot 8.4, 7.4; ear?, 14.6.

Distribution.—Only the Olympic Peninsula, where it has been recorded by [Miller] and [Allen] (1928: 104) from Sol Duc Hot Springs and Lake Cushman.

Description.—Myotis keenii is similar, in general, to Myotis lucifugus and Myotis yumanensis, but the ears are longer and when laid forward reach about 4 mm. past the nose rather than ending at the nostrils. The foot is of medium size (about 8 mm.) and no keel is present on the calcar.

The distribution of this species is given by [Miller] and [Allen] (1928: 101) as "northern North America from the limits of tree growth south in the east to South Carolina and Arkansas, and in the west to northwestern Washington."

I have not observed this bat in Washington and know nothing of its habits. Its distribution is most unusual. Its range seems to lie only in the glaciated area of western British Columbia and northern Washington.

Myotis evotis (H. [Allen])
Long-eared myotis

Description.—The distinguishing feature of Myotis evotis is its long ears, which, when laid forward, reach 5 mm. in front of the nose. Myotis thysanodes and Myotis keenii, other species in which the ears are rather long, have the ears ending less than 5 mm. anterior to the nose when laid forward. The foot of Myotis evotis is of moderate size (8 to 9 mm.).

This species ranges over the western United States, from British Columbia to central Mexico. Two subspecies of this interesting bat are recognized, both of which occur in Washington.