Perognathus parvusGreat Basin pocket mouse
Geographic Range
This pocket mouse can be found in the Great Basin from South British Columbia (Canada), south to eastern California and east to southeast Wyoming and northwest Arizona (Wilson 1993).
Habitat
The Great Basin pocket mouse can be found in shrub/grassland communities of sagebrush, shadscale, greasewood, mountain mahogany, and bitterbrush. Habitats dominated with shrub are useful in vegetative cover, while also providing better and more diverse food resources (Bushey 1987).
- Terrestrial Biomes
- desert or dune
- savanna or grassland
Physical Description
Head and body length: 60-90 mm Tail length: 45-100 mm
The upper parts of its body are a pinkish buff color, which is thinly to heavily overlaid with a blackish color, while the underparts vary from white to buffy. The soft coat of this mouse has no bristles. One molt takes place in late summer. The soles of its hind feet are hairy, and the tail is long and bicolored (Hall 1981).
Its hind limbs are about the same length of its forelimbs, and the Great Basin pocket mouse moves about on all four legs. While the hind legs provide support, the forefeet dig with claws through sand to find seeds (Nowak 1991). These seeds are then placed in fur-lined external cheek pouches, which open alongside its mouth (Britannica 1997).
- Other Physical Features
- endothermic
- bilateral symmetry
Reproduction
From about late April to early August, males are in breeding condition, while females show the first sign of estrus in April. Early June is probably when breeding occurs at its peak. Pregnancies then occur from May to July. Gestation lasts 21 to 25 days. When there is an abundance of food, females have an average of two litters per year. Some have even been found to have three litters. Otherwise, an average of 1.1 litters is produced. Litters vary from three to eight mice. Juveniles born early in the season are able to breed themselves by late summer (Nowak 1991).
- Key Reproductive Features
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
Lifespan/Longevity
-
- Average lifespan
Status: captivity - 5.8 years
- AnAge
- Average lifespan
Behavior
Most individuals remain underground from December to March, but for the rest of the year they emerge for an average of sixty days to ninety days, depending on the abundance of food. They return to their burrows from late summer to early fall (Bushey 1987). Great Basin pocket mice are nocturnal and stay in their burrows during the day. The entrances of the burrows, usually hidden under shrubs, are covered with earth in order to maintain a low temperature and high humidity (Nowak 1991).
It has been found that the peak population in south-central Washington during autumn was an average of 320 individuals in a 2.7 ha. study area. The home range was 1,560-4,005 square meters for males and 508-2,301 square meters for females (Nowak 1991).
- Key Behaviors
- motile
Communication and Perception
Food Habits
Its diet consists mostly of seeds of forbs, grasses and shrubs. Along with green vegetation, insects are eaten particularly when they are abundant (Grzimek 1990).
Conservation Status
Great Basin pocket mice are common and not endangered (Grzimek 1990). Because they are able to retreat to underground burrows, these mice are not in much immediate danger from fires in sagebrush and bunch grass habitats. However, fires reduce food resources and vegetative cover, making the mice more susceptible to predators (Bushey 1987).
-
- IUCN Red List
-
Least Concern
More information
Other Comments
The family name of Heteromyidae comes from the Greek "heteros", meaning "the other, different from the usual," while the genus name of Perognathus comes from two words in Greek. "Pera" means "a pouch, a pocket," and "gnathos" is "the jaw, the mouth" (Gotch 1979).
Contributors
Janette Luu (author), 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.
- 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
- 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.
- 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
Britannica Online. 1997. Pocket Mouse. http://www.eb.com/cgi-bin/g?keywords=pocket%20mouse
Bushey, C.L. 1987. Perognathus parvus. http://www.fs.fed.us/database/feis/animals/Mammal/PEPA/Introductory.html
Gotch, A. F. 1979. Mammals - Their Latin Names Explained. Blandford Press Ltd.: Poole, Dorset.
Grzimek, B. 1990. Grzimek's Encyclopedia of Mammals. McGraw-Hill Publishing Company: New York.
Hall, E. R. 1981. The Mammals of North America. John Wiley and Sons, Inc.: New York.
Nowak, R. M. 1991. Walker's Mammals of the World. The Johns Hopkins University Press: Baltimore.
Wilson, D. E. and D. M. Reeder. 1993. Mammal Species of the World. Smith Institution Press: Washington.