Tawny-bellied cotton rat

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

Tawny-bellied cotton rat (Sigmodon fulviventer) is a small rodent in the Cricetidae family. It lives in Mexico and in the U.S. states of Arizona and New Mexico. It is listed as Least Concern by the IUCN.

Appearance: Males and females look alike. An adult male weighs about 222 g and a female about 206 g. Its tail has scales and hair. It is different from the hispid cotton rat by its shorter, broader skull and by its tail and fur pattern. The fur on the belly is tawny; the back is black and tan. There are several kinds of fur hairs, with the longest being the guard hairs. Whiskers on the face help it stay balanced while swimming.

Habitat and diet: It lives in grasslands and likes dense grass. It makes grass-covered runways to move around. It eats grasses, especially bunchgrass, and uses grass to build nests.

Range and climate: Its range starts in central Mexico and extends into central/southwestern New Mexico and southeastern Arizona. As climate changes bring more rain and warmer temperatures, its range in New Mexico is expanding westward.

Ecology and relationship with others: It shares nearby areas with the hispid cotton rat. The tawny-bellied tends to prefer moister places; the hispid prefers drier areas. They usually avoid each other, but there is indirect competition. In Durango, Mexico, the tawny-bellied is often the dominant species because it is a habitat specialist.

Research use: This rat is used to study human diseases and test vaccines and therapies. It can be infected with several human diseases, including respiratory viruses, pulmonary tuberculosis, and HIV-1, and may show a similar immune response to humans. Because it is easy to care for and there are inbred strains, it is a common model for experiments. Scientists are exploring TB and HIV-1 co-infection studies using this species.