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The Mammals of Texas -
Online Edition Hispid Pocket Mouse
Habits. These large pocket mice prefer areas of sand or other friable soil covered with scattered to moderate stands of herbaceous vegetation. The margins of brush fields and the rank growth in fence rows offer suitable cover. Dense stands of grasses and brush usually are avoided. Their burrows are always dug in friable soil. They have been described as resembling 1-inch (25 mm) auger holes bored straight into the ground. Usually all the dirt excavated from the burrow system is piled near one opening, leaving the others inconspicuous and without mounds. The openings usually are plugged in the daytime. A burrow excavated in Brazos County had two openings, neither of which was plugged, connected by a single tunnel that descended to a depth of about 40 cm. A side branch contained food and nest chambers. Another burrow was found opening under a log which served as a roof for the nest chamber. These mice have been known to inhabit deserted burrows of Mexican ground squirrels in central Texas. Their nest is composed of shredded dry grasses and weeds. In captivity, the mice pile the nesting material into a loose heap and then mat it down by sleeping on top of the structure. They seem to behave likewise in the wild. They appear to be active through most of the year in the southern part of their range, but they probably "hibernate," or at least hole up, in winter in north Texas. Their food consists almost entirely of vegetation, principally seeds. Frank Blair found the seeds of gaillardia, cactus, evening primrose, and winecup most frequently in their caches; in addition, he lists 23 other species of plants that were utilized. In Texas a cache of about one-half liter of Diodia teres (Poor Joe) seeds was found and in another instance the store was entirely seeds of sandbur grass (Cenchrus). Animal matter makes up only a small part of their diet. Blair lists grasshoppers, caterpillars, and beetles. Judging from records of capture of juveniles, one or two litters of young are produced in the northern part of the range, but breeding is practically continuous throughout the year in south Texas. Young animals out of the nest (about 1 month old) have been captured as early in the year as January 8 and as late as October 14. Based on embryo counts, the litter varies from two to nine, averaging six. Nothing is known regarding the gestation period or the growth and development of the young. ln sandy-land farming areas these mice can do considerable damage by digging up and carrying away planted seeds of cantaloupe, watermelon, peas, and small grains. In range and pasture lands they perform a service by eating seeds of weeds. Remarks. In previous editions, this mouse was included in the genus Perognathus; however, recent taxonomic studies have shown that it, along with all spiny-rumped pocket mice of Texas, should be included in a separate genus, Chaetodipus. Formerly included with hispidus in the Perognathus species group, the desert pocket mouse (C. penicillatus), rock pocket mouse (C. intermedius), and Nelson’s pocket mouse (C. nelsoni) are all now included in the genus Chaetodipus. Photo credit: W. B. Davis. |
Description. A medium to large pocket
mouse with harsh pelage and large hind foot, the sole of
which is naked to the heel; tail less than half of total
length, distinctly bicolor, sparsely haired, and lacking
tuft; upperparts olive buffy, lined with black; lateral
line wide and clear buff; underparts white. External
measurements average: total length, 198 mm; tail, 93 mm;
hind foot, 24 mm. Weight of adults, 30-47 g. Dental
formula as in 