Hispid Cotton Rat
This common rat of open habitat occurs across the state.
Description: A small, robust rodent with long, coarse fur and a tail shorter than the total body length. The fur color on the upperparts is a mixture of brown, tan, black, and gray, while the underside is grayish or buff. The scaly, thinly furred tail is dark above and light below. Hidden in the hair are large ears; eyes are moderately large as well.
Length: 8.0 - 14.6 inches
Tail: 3.0 - 6.6 inches
Ears: 0.5 - 1.0 inch
Weight: 2.0 - 8.5 ounces
- Brown Rats are larger in size, have longer tails, have shorter fur, and lack grizzling in the fur.
- Marsh Oryzomys has a more slender build, longer tail, and shorter, less-grizzled fur.
- Eastern Woodrat is larger, has a well-haired tail, and lack of grizzling in the fur.
Habitat: Occurs primarily in open fields or borders of fields with dense, grassy growth. Also, occurs along borders of agricultural fields and along roadsides. They build small nests of grasses, plant fibers, or other materials under rocks or logs. A system of runways is created as the rats move around in the soil and grass.
Diet: Feeds primarily on plant material including stems, leaves, roots, and seeds of grasses and sedges, and domestic crops. However, they will occasionally eat crayfish, insects, ground-nesting bird eggs and chicks, and dead carcasses.
Breeding information: Hispid Cotton Rats are incredibly prolific mammals, but their huge reproductive potential is kept in check by bird, snake, and mammal predators. Breeding occurs all year long, but slows down in the winter. Females are able to breed beginning at 8 weeks old and go into heat every 7-9 days if unmated. The gestation period is 27 days and they produce several litters per year. Litter sizes range from 1-12 (average 5-7) young. Young are weaned after 15-20 days.
Status in Tennessee: Hispid Cotton Rats are common over much of their range and populations are stable.
- Like their name suggests Hispid Cotton Rats were first discovered around the cotton plantations in the south, where they can be abundant.
- Hispidus means "rough" in Latin and refers to the stiff guard hairs of the coat.
Best places to see in Tennessee: Borders of dense, grassy fields or cultivated fields.
For more information:
Meikle, D. and K. Francl 2011. "Sigmodon hispidus" (On-line), Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/information/Sigmodon_hispidus.html
Schwartz, C.W. and E.R. Schwartz. 2001. The Wild Mammals of Missouri, 2nd Edition. University of Missouri Press and Missouri Department of Conservation, Columbia, MO.