||The Mammals of Texas -
Plains Pocket Mouse
Rodentia : Family Heteromyidae
: Perognathus flavescens Merriam
Description. A small, silky,
yellowish-buff pocket mouse; upperparts more or less
washed with blackish; pelage relatively short. External
measurements average: total length, 130 mm; tail, 61 mm;
hind foot, 17 mm. Weight of adults, 8-11 g. The dental
formula, as in all heteromyids, is I 1/1, C 0/0, Pm 1/1,
M 3/3 X 2 = 20.
Distribution in Texas. A mouse of the
Great Plains region. Recorded in Texas from El Paso
County and from High Plains and adjacent areas in
northwestern part of state, south to Ward County.
Habits. This little pocket mouse
is partial to sandy soils covered with sparse vegetation.
In the sandhills of the Texas Panhandle its burrows are
commonly excavated beneath clumps of Spanish bayonet or
prickly pear, the entrances usually so distributed as to
open from under the plant in all directions. Usually the
main entrance is plugged with soil from within during the
day, and if it is opened the mouse closes it again. The
several other inconspicuous openings, hardly large enough
to admit the end of ones finger, are seldom plugged
and may serve as "duck-outs."
Their food is almost exclusively the
seeds of grasses and weeds. Food items found in their
cheek pouches include seeds of needle grass (Stipa),
bind weed, sandbur grass, a small bean (probably Astragulus),
and sedge (Cyperus). Even those caught in grain
fields usually have their pouches filled with weed seeds.
Seeds of two species of pigeon grass, a few other
grasses, and wild buckwheat have been found in their
underground food caches.
Knowledge of their breeding habits is
meager. Females collected in late July and early August
contained four embryos each. Two collected on July 9 and
14 contained four and five embryos. No information is
available on mating, gestation, birth, growth of the
young, and family life.
Remarks. In previous editions
the Apache pocket mouse (Perognathus apache
Merriam) was treated as a separate species; however,
recent taxonomic work on these mice by Dan Williams has
shown they have a karyotype identical with that of P.
flavescens and, morphologically, are quite similar.
Therefore, P. apache is now considered to be
merely a subspecies of P. flavescens.
Photo credit: John L. Tveten.