||The Mammals of Texas -
Rodentia : Family Muridae : Peromyscus
Description. A small, white-footed mouse
with sharply bicolor tail, white beneath and dark above;
ears usually shorter than hind foot, prominent and
leaflike; upperparts bright fulvous or brownish,
intermixed with dusky; underparts and feet white.
External measurements average: total length, 170 mm;
tail, 81 mm; hind foot, 20 mm; ear, 18 (12-20) mm.
Weight, 15-32 g.
This species is most easily confused
leucopus, from which it
differs in (1) sharply bicolor tail, (2) more hairy and
often shorter tail, (3) frequently whitish tufts of hair
at base of ears, and (4) usually longer pelage.
Distribution in Texas. Statewide but
uncommon in the eastern, coastal, and southern parts of
Habits. These mice occupy a
variety of habitats, ranging from mixed forests to
grasslands to open, sparsely vegetated deserts. In Texas,
they usually inhabit grasslands or areas of open brush,
especially where weeds and grasses offer concealment and
a source of food. Weed-choked fence rows and washes offer
almost ideal habitat. Mice of this group seem to be poor
climbers and live close to or on the ground.
They are almost strictly nocturnal.
Trapping records indicate that they leave their daytime
retreats early in the evening and remain abroad until
shortly after sun up. They live in underground burrows,
in brush piles, or in crevices among rocks. The burrow is
simple in design and usually consists of two or three
short branches converging from as many surface openings
to a single tunnel that slopes steeply to the globular
nest chamber which is 7-10 cm in diameter. The nests are
hollow balls of dry grass, shredded weed stems, and other
available material including rabbit fur and bird
Deer mice do not hibernate. Their
winter activities may include taking up quarters in a
pile of logs, from which they venture nightly in search
of food. The tracks of one mouse led from the logs to one
bush after another in a wandering fashion to the edge of
a bare field some 100 m distant and then back to the log
pile. The others traveled less than 50 m from their
headquarters. Bits of bark, leaves, and seed coats
scattered on the snow beneath many of the bushes
indicated that they had climbed into them in quest of
food. Their food consists of a variety of items, chiefly
seeds. In season fruits, bark, roots, and herbage are
also consumed and, judging from the behavior of these
mice about camps, nearly everything edible is sampled.
Deer mice breed in every month of the
year, with peaks in the periods from January through
April and from June through November. Litters seem to be
born in rapid succession one captive female
produced 11 litters with 42 young in a year. The
gestation period varies from 22 to 27 days, averaging
about 24 days. Litter size ranges from one to nine,
averaging about four. At birth the young are blind, pink,
and hairless and weigh from 1.1 to 2.3 g. They become
pigmented dorsally in about 24 hours, the pinna of the
ear unfolds on the third day, the eyes open in 12-17
days, and they are weaned when about 4 weeks old. The
longest observed time of suckling is 37 days. Sexual
maturity is reached before the young lose their
"blue" juvenile pelage, and females born early
in the year may themselves produce young by late summer
or early fall.
These mice are often abundant in
favorable habitats and then, as with other animals that
overpopulate an area, they may become troublesome.
Because of their tolerance to a wide variety of habitat
conditions and their often large population they are
difficult and expensive to control. Since they are an
important source of food for many small carnivores, owls,
and snakes, the assistance of these animals should be
enlisted in keeping the populations of mice within
Photo credit: R. M. Bond.