By B. Lucas Stafford
Geographic Range
The hispid cotton rat ranges from southern Virginia west to Nebraska extending south to northern South America. (Hall, 1981)
Habitat
Hispid cotton rats exist in a wide range of habitats. However, the presence of grassy patches with some overstory of shrubbery seems to be a requirement. (Cameron & Kincaid, 1985)
Terrestrial Biomes:
desert or dune 
; savanna or grassland ; chaparral .
Physical Description
(2.82 to 5.28 oz; avg. 4.05 oz)
Total Length: 270 mm. This is a large, robust rat with grizzled brown fur dorsally and grayish-white fur ventrally, and stiff black guard hairs. The last two molar teeth are in an "S"-shaped pattern. The hind feet have six plantar tubercles and the second, third, and fourth digits are longer than the first and second. The tail is shorter than the head and body. (Davis & Schmidly, 1994)
Some key physical features:
endothermic ; bilateral symmetry .
Reproduction
Breeding occurs at all time of the year except during the coldest winter months. Gestation is approximately 27 days. The maximum litter size is 15. The precocial offspring are weaned in 10-15 days and are sexually mature by 40 days. (Cameron & Spencer, 1981)
Key reproductive features:
gonochoric/gonochoristic/dioecious (sexes separate); sexual .
Behavior
Females construct ball-shaped nests of woven grasses on the soil surface or within a burrow. (Cameron & Spencer, 1981)
Key behaviors:
motile .
Food Habits
Although hispid cotton rats are omnivorous, they mainly feed upon green vegetation. However, cotton rats are opportunistic and will eat almost anything. (Martin, et al., 1951)
Economic Importance for Humans: Negative
The hispid cotton rat normally occurs at moderately low population levels. However, its population density is a function of the amount of habitat present. The amount of habitat present is directly correlated to rainfall. During times of increased precipitation their populations have been known to become incredibly dense. Estimates have been as high as several hundred per hectare. This has devastating effects on crop yields for farmers. (Davis & Schmidly, 1994)
Other Comments
The hispid cotton rat has been shown to have some resistance to the venom of the western diamondback rattlesnake. (Garcia, et al.,1979)
Contributors
B. Lucas Stafford (author), Southwestern University.
Stephanie Fabritius (editor), Southwestern University.
