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.