Chapter IV: Part 4

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

Order MARSUPALIA--marsupials

Family DIDELPHIIDAE--opossums
Genus =Didelphis= Linnaeus--opossums
_Didelphis virginiana virginiana Kerr_ opossum

Order INSECTIVORA--insectivores

Family TALPIDAE--moles
Genus =Neurotrichus= Gunther--shrew-mole
_Neurotrichus gibbsii gibbsii_ (Baird) }
_Neurotrichus gibbsii minor_ Dalquest } Gibbs shrew-mole
and Burgner }

Genus =Scapanus= Pomel--western American moles
_Scapanus townsendii_ (Bachman) Townsend mole
_Scapanus orarius orarius_ True }
_Scapanus orarius yakimensis_ Dalquest } coast mole
and Scheffer }
_Scapanus orarius schefferi_ Jackson }

Family SORICIDAE--shrews
Genus =Sorex= Linnaeus--long-tailed shrews
_Sorex cinereus cinereus_ Kerr }
_Sorex cinereus streatori_ Merriam } cinereous shrew
_Sorex merriami merriami_ Dobson Merriam shrew
_Sorex trowbridgii trowbridgii_ Baird }
_Sorex trowbridgii destructioni_ Scheffer } Trowbridge shrew
and Dalquest }
_Sorex vagrans vagrans_ Baird }
_Sorex vagrans monticola_ Merriam } wandering shrew
_Sorex obscurus obscurus_ Merriam }
_Sorex obscurus setosus_ Elliot } dusky shrew
_Sorex palustris navigator_ (Baird) mountain water-shrew
_Sorex bendirii bendirii_ (Merriam) }
_Sorex bendirii albiventer_ Merriam } Bendire water-shrew

Genus =Microsorex= Coues--pigmy shrew
_Microsorex hoyi washingtoni_ Jackson pigmy shrew

Order CHIROPTERA--bats

Family VESPERTILIONIDAE--vespertilionid bats
Genus =Myotis= Kaup--mouse-eared bats
_Myotis lucifugus carissima_ Thomas }
_Myotis lucifugus alascensis_ Miller } big myotis
_Myotis yumanensis sociabilis_ }
H. W. Grinnell }
_Myotis yumanensis saturatus_ Miller } Yuma myotis
_Myotis keenii keenii_ (Merriam) Keen myotis
_Myotis evotis evotis_ (H. Allen) } long-eared myotis
_Myotis evotis pacificus_ Dalquest }
_Myotis thysanodes thysanodes_ Miller fringe-tailed myotis
_Myotis volans longicrus_ (True) } hairy-winged myotis
_Myotis volans interior_ Miller }
_Myotis californicus caurinus_ Miller } California myotis
_Myotis californicus californicus_ }
(Audubon and Bachman) }
_Myotis subulatus melanorhinus_ (Merriam) small-footed myotis

Genus =Lasionycteris= Peters--silver-haired bat
_Lasionycteris noctivagans_ (Le Conte) silver-haired bat

Genus =Corynorhinus= H. Allen--long-eared bats
_Corynorhinus rafinesquii townsendii_ } long-eared bat
(Cooper) }
_Corynorhinus rafinesquii intermedius_ }
H. W. Grinnell }

Genus =Pipistrellus= Kaup--pipistrelles
_Pipistrellus hesperus hesperus_ (H. Allen) western pipistrelle

Genus =Eptesicus= Rafinesque--serotine bats
_Eptesicus fuscus bernardinus_ Rhoads big brown bat

Genus =Lasiurus= Gray--hairy-tailed bats
_Lasiurus cinereus cinereus_ (Beauvois) hoary bat

Genus =Antrozous= H. Allen--nyctophiline bats
_Antrozous pallidus cantwelli_ Bailey pallid bat

Order CARNIVORA

Family URSIDAE--bears
Genus =Ursus= Linnaeus--bears
_Ursus americanus altifrontalis_ Elliot }
_Ursus americanus cinnamomum_ } black bear
(Audubon and Bachman) }
_Ursus chelan_ Merriam grizzly bear

Family PROCYONIDAE--raccoons and allies
Genus =Procyon= Storr-raccoons
_Procyon lotor psora_ Gray }
_Procyon lotor excelsus_ Nelson and } raccoon
Goldman }

Family MUSTELIDAE--weasels and allies
Genus =Martes= Pinel--martens and fisher
_Martes caurina caurina_ (Merriam) } western marten
_Martes caurina origenes_ (Rhoads) }
_Martes pennanti_ (Erxleben) fisher

Genus =Mustela= Linnaeus--weasels, ferrets and minks
_Mustela erminea invicta_ Hall }
_Mustela erminea fallenda_ Hall }
_Mustela erminea olympica_ Hall } ermine
_Mustela erminea streatori_ (Merriam) }
_Mustela erminea gulosa_ Hall }
_Mustela erminea murica_ (Bangs) }
_Mustela frenata washingtoni_ (Merriam) }
_Mustela frenata altifrontalis_ Hall }
_Mustela frenata effera_ Hall } long-tailed weasel
_Mustela frenata nevadensis_ Hall }
_Mustela vison energumenos_ (Bangs) mink

Genus =Gulo= Pallas--wolverines
_Gulo luscus luteus_ Elliot wolverine

Genus =Lutra= Brisson--river otters
_Lutra canadensis pacifica_ Rhoads }
_Lutra canadensis vancouverensis_ Goldman } river otter

Genus =Enhydra= Fleming--sea otter
_Enhydra lutris nereis_ (Merriam) sea otter

Genus =Spilogale= Gray--civet cats or spotted skunks
_Spilogale gracilis saxatilis_ Merriam } civet cat or
_Spilogale gracilis latifrons_ Merriam } spotted skunks

Genus =Mephitis= Geoffroy and Cuvier--striped skunks
_Mephitis mephitis hudsonica_ Richardson }
_Mephitis mephitis major_ (Howell) }
_Mephitis mephitis notata_ (Howell) } striped skunk
_Mephitis mephitis spissigrada_ Bangs }

Genus =Taxidea= Waterhouse--American badger
_Taxidea taxus taxus_ (Schreber) badger

Family CANIDAE--foxes, coyote, wolves and dogs
Genus =Vulpes= Oken--foxes
_Vulpes fulva cascadensis_ Merriam red fox

Genus =Canis= Linnaeus--coyote, wolves and dogs
_Canis latrans testes_ Merriam }
_Canis latrans incolatus_ Hall } coyote
_Canis lupus fuscus_ Richardson wolf
_Canis familiaris_ Linnaeus dog

Family FELIDAE--cats
Genus =Felis= Linnaeus--true cats
_Felis concolor oregonensis_ Rafinesque } cougar or
_Felis concolor missoulensis_ Goldman } mountain lion

Genus =Lynx= Kerr--lynxes and bobcats
_Lynx canadensis canadensis_ Kerr Canadian lynx
_Lynx rufus fasciatus_ Rafinesque }
_Lynx rufus pallescens_ Merriam } bobcat

Order PINNIPEDIA--seals and walruses