Perognathus parvus
(Great Basin Pocket Mouse)

Order: Rodentia
Order Description:Rodents
Family: Heteromyidae
Family Description:
Pocket Mice,Kangaroo Mice and Rats

The Great Basin pocket mouse is slightly larger than the “Little pocket mouse”. Its DorsalClick word for definition surface is yellowish occasionally with a pinkish tone to olive-buff. The ventral surface is buffClick word for definition to white. Its long tail is dark above to white below with a small tuft of hairs on the tip. Total length is about 5 ¾ to 7 ¾ inches (148-198 mm) with a tail of about 3 to 4 ¼ inches (77-107 mm).

From south-central British Columbia, south to southern California, northern Arizona, and southwestern Wyoming.

Found on arid, sandy, short-grass steppes, shrub steppeClick word for definition, and pinyon/juniper woodlands. Usually found in habitats with light-textured, deep soils. Also found among rocks. In Idaho, prefers sagebrush, rabbitbrush, and bitterbrush, as well as grassy fields.

Primarily a seed eater, but in spring and summer also feeds on insects and some green vegetation.

Above-ground activity of the Great Basin pocket mouse decreases from October through March when this pocket mouse is hibernating. They may also become torpidClick word for definition in the summer in response to a lack of food or inclement weather. They tend to be nocturnalClick word for definition or crepuscularClick word for definition and they have been shown to be active within an hour after sunset. They store seeds in underground chambers. They may forage in grain fields but rarely, and only when their populations are very high, are they a problem for farmers or ranchers. They are primarily solitary. Their home range has been estimated at up to 1 acre (0.40 ha). In years with abundant precipitationClick word for definition, population density may reach 80 per 2.5 acres (1ha) or more. Their burrows are often at the base of sagebrush and packed piles of soil near the burrow entrance is a diagnostic sign for this species. Predators include snakes, hawks, owls, weasels, badgers and no doubt, other common carnivores.

The Great Basin pocket mouse mates after it emerges from hibernationClick word for definition in late March or during April. GestationClick word for definition probably lasts about 22 to 25 days. A female can produce 2 litters per year; the number varies with precipitationClick word for definition. Litter size ranges from 2 to 8 (average about 5). Young are weanedClick word for definition in about 3 weeks. An Idaho study found males were sexually active March-August; juvenile females bred during their first year; males generally did not.

Status: Unprotected nongame species

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Important State References:
Speth, R.L, C.L. Pritchett, and C.D. Jorgensen. 1968. Reproductive activity of Perognathus parvus. J. Mammal. 49:336-337.

Information written by Donald Streubel,© 2000
Map image provided by
Stephen Burton,© 2000
Design by Ean Harker©1999, 2000.