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Chaetodipus penicillatusdesert pocket mouse

By Lukasz Chebes

Geographic Range

Chaetodipus penicillatus occurs in the southwestern United States and northern Mexico. The northern limit of its range is southern Nevada. It extends southwest into California and the northern Baha Peninsula and northwestern Mexico. Eastward it stretches into the southwesternmost parts of Utah. From southern Nevada and southwestern Utah the range of Chaetodipus penicillatus proceeds southeast into Arizona, through southern New Mexico and southwestern Texas, and into northeastern Mexico (Burt and Grossenheider, 1976; Lee, Riddle, and Lee, 1996; Patton, 1996; Utah Division of Wildlife Resources, 2001).

Habitat

Chaetodipus penicillatus is found in various arid, open desert environments, usually where the vegetation is rather sparse. These may include desert wash, desert succulent shrub, desert scrub, and alkali desert scrub. It prefers soft alluvian, sandy, or silty soils along stream bottoms, desert washes, and valleys, rather than rocky terrain. These pocket mice live in soils that may be populated by creosote bush, cholla, palo verde, burroweed, mesquite, cacti, and short, sparse grass, as well as in lower edges of alluvial fan with yucca, mesquite, grama, and prickle poppy. (Biota Information System of New Mexico, 2000; Brylski, 2001; Burt and Grossenheimer, 1976)

  • Range elevation
    0 to 820 m
    0.00 to 2690.29 ft

Physical Description

Chaetodipus penicillatus is a medium-sized pocket mouse. The total length of adults usually does not exceed 180 mm. Coloration is grayish brown to yellowish gray and may be sprinkled with black. The pelage is coarse. This species lacks rump spines but has numerous, elongate rump hairs which are darker dorsally and lighter laterally. There is no lateral line. The underparts of the body and tail are whitish. The tail is heavily crested and is longer than the head and body, with average tail length being 109 mm. The soles of the hind feet are whitish and average hind foot length is 25 mm. The dental formula of Chaetodipus penicillatus is the same as in all heteromyids: I 1/1, C 0/0, P 1/1, M 3/3 X 2 = 20 (Bradley 1997; Burt and Grossenheider, 1976).

  • Range mass
    11 to 22 g
    0.39 to 0.78 oz
  • Range length
    157 to 199 mm
    6.18 to 7.83 in

Reproduction

Chaetodipus penicillatus has a high population turnover rate, as high as 95% annually. Female desert pocket mice may give birth to one or more litters of young from the early spring to the late summer. Many young females reach sexual maturity early and became pregnant while still in their juvenile pelage (Biota Information System of New Mexico, 2000; Bradley, 1997; Utah Division of Wildlife Resources, 2001).

  • Breeding season
    early spring to late summer
  • Range number of offspring
    1 to 7
  • Average gestation period
    23 days

Lifespan/Longevity

Few individuals survive more than one year, either in captivity and in the wild (Bradley, 1997).

  • Average lifespan
    Status: wild
    1 years
  • Average lifespan
    Status: captivity
    1 years
  • Average lifespan
    Status: wild
    1 years
  • Average lifespan
    Status: captivity
    1 years

Behavior

Chaetodipus penicillatus may be active all year round in some areas, though it is inactive in the winter in southern Arizona. This species is mainly nocturnal. It is aggressively solitary, with a home range of less than 1 acre. Pocket mice can burrow into hard-crusted soils by actually physically chewing their way through the hard portions of the soil. Their burrows, however, are usually excavated in silty, sandy, or gravelly soil and are used for refuges, seed storage, and neonatal care. (Arnold 1942; Brylski, 2001).

Communication and Perception

Food Habits

Chaetodipus penicillatus forages beneath a canopy of shrubs on sandy or gravely soils. It feeds primarily on seeds of forbs, grasses, and shrubs, although green vegetation and insects may supplement the diet. Seeds of mesquite, creosote bush, and broomweed have been found in the cheek pouches of desert pocket mice. Seeds are also stored in burrows and in dispersed caches throughout their territories. Although there is no direct evidence, this species probably acquires all of the water it needs from its food (Arnold, 1942; Bradley, 1997; Brylski, 2000).

  • Animal Foods
  • insects
  • Plant Foods
  • leaves
  • seeds, grains, and nuts

Predation

Ecosystem Roles

Chaetodipus penicillatus is a granivore, specialized for extreme arid environments. Its competitors include other members of the family Heteromyidae, especially Dipodomys merriami, as well as cricetids (Brylski, 2000).

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

May play a role in spreading seeds that it feeds on.

Economic Importance for Humans: Negative

Could possibly be a crop or household pest.

Conservation Status

Other Comments

Desert pocket mice have exceedingly long renal papillae which function to concentrate the urine and results in a reduction of water loss (Biota Information System of New Mexico, 2000).

Contributors

Lukasz Chebes (author), University of Michigan-Ann Arbor, Kate Teeter (editor), University of Michigan-Ann Arbor.

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

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

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.

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

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.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

internal fertilization

fertilization takes place within the female's body

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.

seasonal breeding

breeding is confined to a particular season

sexual

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

solitary

lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Arnold L, W, 1942. Notes on the life history of the sand pocket mouse. Journal of Mammalogy, 23: 339-341.

Biota Information System of New Mexico, 2000. "Desert Pocket Mouse" (On-line). Accessed November 18, 2000 at http://www.fw.vt.edu/fishex/nmex_main/species/050440.htm.

Bradley L, 1997. "Desert Pocket Mouse" (On-line). Accessed November 17, 2001 at http://www.nsrl.ttu.edu/tmot1/chaepeni.htm.

Brylski, P, 2000. "Desert Pocket Mouse" (On-line). Accessed November 17, 2001 at http://www.dfg.ca.gov/whdab/cwhr/M093.html.

Burt, W. H., , Grossenheider, R. P. 1976. A Field Guide to the Mammals. Boston: Houghton Mifflin Company.

Lee, T. E. Jr., , Riddle, B. R., Lee P. L. 1996. Speciation in the Desert Pocket Mouse. Journal of Mammalogy, 77: 58-68.

Patton, J. L, 1993. *Chaetodipus penicillatus*. Pp. 484 in D Wilson, D Reeder, eds. Mammal Species of the World. Washington, D. C: Smithsonian Institution Press.

Utah Division of Wildlife Resources, 2001. "Desert Pocket Mouse" (On-line). Accessed November 17, 2001 at http://www.utahcdc.usu.edu/rsgis2/Search/Display.asp?FlNm=chaepeni.

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