Chaetodipus hispidushispid pocket mouse

Geographic Range

In the United States, the range of these creatures extends from the western Great Plains to the eastern Rockies and southeastern Arizona, and from northern Mexico to North Dakota (Chaetodipus hispidus 1999).

Habitat

Sandy soil scattered with some vegetation is usually the ideal environment for these pocket mice. They are most common in shortgrass priaries, grasslands, or near the growth by fence rows. The best explanation for their choice of habitat is probably the way they make their homes. They dig burrows into the soil, starting with a hole an inch in diameter straight into the ground. C. hispidus create many openings to their burrow, but usually end up piling all the dirt near one opening to camouflage the others. They usually plug these openings during the daytime. These burrows serve as food storage and nesting sites, as well (Davis and Schmidly 1994).

Physical Description

Chaetodipus hispidus are fairly large mice in comparison to other pocket mice. They have heavier hindlimbs compared to their forelimbs. The soles of their hind feet are hairless. These mice have tails less than half the total length of their body with little or no hair on the tail (Chaetodipus hispidus 1999). Another unique feature that many of the mice in this species has is tail-tip albinism. The cause for this phenomenon is not completely understood, but it is another feature that sets apart this species (Stangl, et al 1995). They show definite bicoloration; the belly has light coloring, and the back has olive buff hairs. The average external measurements for a Texan specimen is body length of 198 mm, tail length of 93 mm, and ear length of 10 mm (Davis and Schmidly 1994).

  • Range mass
    30 to 47 g
    1.06 to 1.66 oz

Reproduction

Their nests are usually composed of dry grass and weeds. While the breeding season peaks from May to June, some of the far south Texas specimens may mate all year long. The average litter size is about 6 young, but the precise number is variable with climate, location, and availability of resources (Wild Animals of North America 1995). Very little is known about the gestation period or growth and development periods of the young.

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual

Behavior

There is a definite home range for C. hispidus of about 0.30 hectare. These mice seem to be solitary or antisocial. This solitary behavior is further exaggerated by the state of torpor that most of them undergo on a daily basis during the winter months. While not a true hibernator, every hour that their body temperature falls under eleven degrees Centigrade, they go into an inactive state of torpor to survive the cold. In the southernmost range, the weather usually remains warm enough that C. hispidus remain active throughout the year (Chaetodipus hispidus 1999).

Communication and Perception

Food Habits

C. hispidus are generally seed eaters, but have been known to consume insects. Their diet include seeds of cactus, evening primrose, and winecup, while the insects are usually grasshoppers, caterpillars, and beetles (Caire, et al 1989).

Economic Importance for Humans: Positive

Ranchers are protective of C. hispidus because they eat the seeds of weeds. This is beneficial because harmful weeds no longer spring up to pose danger to the livestock. These little pocket mice perform a great service for ranchers (Davis and Schmidly 1994).

Economic Importance for Humans: Negative

While they do perform good works, C. hispidus is greatly disliked in the farming industry because they carry away the produce the farmers have worked hard to grow. As seed eaters, the mice also dig up the seeds of cantaloupe, peas, watermelon, squash, and other small grains that have been already been planted (Davis and Schmidly 1994).

Conservation Status

C. hispidus are abundant in the wild. They seem to have built-in mechanism to control the population, since it has been found that there are periodic fluctuations. This can probably be attributed to the variables that surround the litter size (Stangl, et al 1995). They are preyed upon by a wide variety of predators, such as coyotes, skunks, snakes, hawks, and owls, but seem to maintain a healthy levels of their population (Chaetodipus hispidus 1999).

Other Comments

Only as late as 1983 were these mice classified under the genus Chaetodipus. Previously they were part of the genus Perognathus. However, taxonomic research has supported the grouping that all spiny-rumped mice, including the Hispid pocket mouse, fall into a new genus named Chaetodipus (Caire, et al 1989).

Contributors

Ida Park (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5? N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

References

1995. Wild Animals of North America. Washington, D.C.: National Geographic Society.

"Chaetodipus hispidus (Hispid Pocket Mouse)" (On-line). Accessed November 14, 1999 at http://www.barkingfrog.com/k-rats/heteromyid/c_hispid.html.

Caire, W., J. Tyler, B. Glass, M. Mares. 1989. Mammals of Oklahoma. Norman: University of Oklahoma Press.

Davis, W., D. Schmidly. 1994. The Mammals of Texas. Austin: University of Texas Press.

Stangl, F., T. Delizio, W. Hinds. June 95. Spatial and Temporal Distribution of Polymorphism for Tail-tip Albinism in the Hispid Pocket Mouse, Chaetodipus hispidus (Rodentia: Heteromyidae). American Midland Naturalist, 134: 185-189.