Perognathus
parvus
(Great Basin Pocket
Mouse)
Description:
The Great Basin pocket mouse
is slightly larger than the “Little pocket mouse”. Its Dorsal
surface is yellowish occasionally
with a pinkish tone to olive-buff. The ventral surface is buff 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).
Range:
From
south-central British Columbia, south to southern California, northern Arizona,
and southwestern Wyoming.
Habitat:
Found on arid, sandy, short-grass
steppes, shrub steppe, 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.
Diet:
Primarily
a seed eater, but in spring and summer also feeds on insects and some green
vegetation.
Ecology:
Above-ground activity
of the Great Basin pocket mouse decreases from October through March when this
pocket mouse is hibernating. They may also become torpid in the summer in response
to a lack of food or inclement weather. They tend to be nocturnal or crepuscular 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 precipitation, 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.
Reproduction:
The Great Basin pocket
mouse mates after it emerges from hibernation in late March or during
April. Gestation probably lasts about 22
to 25 days. A female can produce 2 litters per year; the number varies with
precipitation. Litter size ranges from
2 to 8 (average about 5). Young are weaned 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.
Conservation:
 Status: |
 Unprotected
nongame species |
|
Global Rank: |
|
|
State Rank: |
S5 |
Important State References:
Speth, R.L, C.L. Pritchett, and C.D.
Jorgensen. 1968. Reproductive activity of Perognathus parvus. J. Mammal.
49:336-337.