Microtus oregoni cantwelli [Taylor], Jour. Mamm., 1:180, August 24, 1920 (type from Glacier Basin, 5,935 ft., Mt. Rainier, Pierce County, Washington).
Fig. 118. Distribution of the creeping mouse, Microtus oregoni oregoni, in Washington.
Type.—Obtained at Astoria, Clatsop County, Oregon, by J. K. [Townsend] in 1836; type in Philadelphia Academy of Natural Sciences.
Measurements.—Ten males and 10 females from southwestern Washington, average, respectively: total length 133, 126; length of tail 35, 32; hind foot 16.9, 16.7; ear 9.8, 9.7; weight 19.3, 19.1 grams.
Distribution.—The Cascade Mountains, the Olympic Mountains, and the lowlands of western Washington.
Remarks.—A large series of topotypes of Microtus o. oregoni in the California Museum of Vertebrate Zoölogy, and the rather large series from Cowlitz County, Washington, show a wide range of variation in color, size, and cranial characters. Specimens from the Cascade and Olympic Mountains seem to average a bit paler than topotypes of oregoni, but are not worthy of recognition as distinct races. Too few topotypes of Microtus o. serpens from British Columbia are available to judge the status of that race with any certainty, but specimens from northwestern Washington are certainly oregoni.
Description.—The creeping mouse is a small species of general microtine form. The head and body measure about 4 inches and the tail about 1-1/2 inches. The ears are small and the eyes tiny, nearly buried in the fur. The fur is short and rather rough. It does not lie back smoothly, thereby giving a woolly appearance. The upper parts are reddish or grayish brown and the underparts are grayish white. The nondescript appearance suggests a young rather than adult mouse.