|The Mammals of Texas -
Silky Pocket Mouse
Rodentia : Family Heteromyidae
: Perognathus flavus Baird
Description. A small pocket mouse with
soft, silky fur, short ears, and short, sparsely haired
tail; upperparts pinkish buff, lightly mixed with black;
underparts pure white; spot behind ear clear buff and
conspicuous; ears light buff on outside, blackish inside;
tail pale buffy, slightly darker above. Closely resembles
merriami, from which it
differs in minor features of the skull and the frequency
of biochemical genetic markers. External measurements
average: total length, 113 mm; tail, 50 mm; hind foot, 16
mm. Weight, 6-8 g. Dental formula as in Perognathus
Distribution in Texas. Known from the
Trans-Pecos and extreme northern Panhandle.
Habits. Silky pocket mice appear
to be more tolerant of habitat conditions than some of
the other species of small pocket mice. In some areas
they are found in rocky situations; in others on hard,
stony soils; and in still others on sands. In most
localities, however, they occur on mellow soils of valley
bottoms where they live among the scattered weeds and
shrubs and burrow in the sand.
As with other species of pocket mice
the burrows of flavus are simple in design,
usually shallow and barely large enough to admit a
mans finger. One excavated near Sierra Blanca,
Texas was in the bank of a dike thrown up to divert water
from the highway. The three openings converged to a
single burrow that led along the dike for a distance of
about 1 m, at no place penetrating more than 10 cm below
the surface. Two side branches diverged from the main
burrow, one of them sloping upward to near the surface.
This branch probably was a "duck-out," because
the occupant escaped from it by breaking through the thin
crust of earth at the blind end of the tunnel. No nest or
store of food was encountered, although this mouse is
known to store food in captivity.
The diet consists wholly of seeds, so
far as known. Juniper berries and seeds of grasses and
weeds provide the bulk of their diet.
The breeding season extends from early
spring to late fall. Half-grown young have been captured
as early as April 16 and as late as September 23, and a
lactating female was captured in December. Probably two
or more litters of two to six young are reared each
season. Nothing is known of the growth and development of
the young and the family relations. An adult female lived
in captivity for more than 5 years, but the age attained
in the wild is probably not more than 2 or 3 years.
Photo credit: John L. Tveten.