Hispid Cotton Rat

Photo Credit: Roger Birkhead

SCIENTIFIC NAME: Sigmodon hispidus

DESCRIPTION: The hispid cotton rat is a moderately large, robust rodent with a scaly, thinly haired short tail. Cotton rats have large eyes and ears; however, the ears are almost hidden by their fur. Cotton rats have coarse fur that is grizzled grayish above with mixed buff and black, and white undersides. Adults average body length is between 5 ¼- 5 ¾” and the tail length averages 3-6 ½”. Adult weight varies from four to eight ounces. Both sexes look alike but males are usually slightly larger than females. Juveniles have shorter, darker hairs when compared to adults.

DISTRIBUTION: The hispid cotton rat occurs over most of the southern United States, from the southeastern tip of California, southern Arizona and New Mexico, north to eastern Colorado, eastward through the southern portions of Kansas and Missouri, through Tennessee and North Carolina, and southward along the Atlantic coast through Florida, the Gulf states, and up the Rio Grande valley. Further south, the hispid cotton rat inhabits Central America and Mexico.

HABITAT:  Cotton rats inhabit dense cover such as thickets, grassy fields, overgrown roadsides, fencerow vegetation adjacent to croplands, meadows, marshland, and weedy ditch banks. The cotton rat will have well defined runways radiating in all directions from the nest site.

FEEDING HABITS: Hispid cotton rats are normally herbivores and feed on roots, stems, leaves, and seeds from a wide variety of plants. Fruits, berries, sugarcane, and nuts are also favored when available. Insects, eggs of ground nesting birds, and carrion are also utilized when available.

LIFE HISTORY AND ECOLOGY: The hispid cotton rat is a very prolific species and will breed throughout the year. Several litters per year are produced with 2-15 young per litter. Gestation is approximately 27 days and the young are weaned by the mother in just 10 - 15 days. Young cotton rats mature quickly and breed for the first time at two to three months of age. Though production for the species is very high annually, the average life span is usually limited to six months. Cotton rat populations fluctuate annually and at peaks in populations size can cause serious damage to a variety of crops, including grains, grasses, alfalfa, peanuts, and sweet potatoes. High cotton rat populations can also be detrimental to ground nesting birds like quail and turkey. Cotton rats also compete with these species for food sources.

REFERENCES:

http://www.ag.auburn,edu/enpl/newschoolipm/Rats.php

http://www.ces.ncsu.edu/nreos/wild/pdf/wildlife/COTTON_RATS.PDF

http://www.dicoverlife.org/nh/tx/Vertebrata/Mammalia/Muridae/Sigmodon/hispidus/

Knopf, Alfred A. 1980. The Audubon Society Field Guide to North American Mammals. Chanticleer Press, Inc., New York Pp. 482-483.

Author: Chris Jaworowski, Wildlife Biologist, Division of Wildlife & Freshwater Fisheries


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