The creeping mouse (subgenus Chilotus) is restricted to the Pacific Coast and ranges from British Columbia to California. In Washington it occupies almost every conceivable "mouse" habitat in its range, including wet marshes, damp ravines, dry forest, damp, mossy forest, meadows, alpine meadows and fields of short grass. It is rare in all but the latter habitat. In fields of short or dry grass it is often abundant. In the Cascade Mountains it was in relatively dry places along streams or rock slides. Altitudinally it ranges from sea level to at least 6,000 feet, and from the Humid Transition well into the Hudsonian life-zones.
Creeping mice construct tiny tunnels among the grass roots and seldom venture out of them. In suitable habitat the surface of the ground beneath the grass is a maze of these tunnels, which cross, intersect, and divide in a complex network. An observer standing in a field occupied by creeping mice can scarcely conceive of the extent and perfection of the tiny tunnel system at his feet.
Creeping mice lived but a day or two in captivity. Save for the bits of grass blades left in their runways, little is known of their food or other life habits. Their nests are round balls of dry grasses placed in cavities under logs. None of the many examined possessed a lining of softer materials. Embryos found in pregnant females from April 10 to May 18 numbered from 2 to 4.
Lagurus curtatus pauperrimus (Cooper)
Sagebrush vole
Arvicola pauperrima Cooper, Amer. Nat., 2:535, December, 1868.
Arvicola pauperrimus [Merriam], N. Amer. Fauna, 5:64, July 30, 1891.
L[agurus]. pauperrimus Thomas, Ann. and Mag. Nat. Hist., ser. 8, 9:401, April, 1912.
Microtus pauperrimus [Bailey], N. Amer. Fauna, 55:214, August 29, 1936.
Lemmiscus pauperrimus [Davis], Recent Mamm. Idaho, Caxton Printers, p. 327, April 5, 1939.