The hispid cotton rat reaches Colorado only at the far northwestern edge of its range, which makes it one of the state’s more localized rodents here. Open occurrence databases hold 198 records for it in Colorado, a small tally that reflects both its restricted range and its secretive, ground-hugging life.
A grassland rat of the southeast corner
A stocky rat with coarse, grizzled brown fur, the cotton rat lives in dense grass and weedy tangles, cutting distinct runways through the vegetation as it feeds. In Colorado it is essentially a southeastern animal, holding to the lower Arkansas River valley and shortgrass country of Baca, Pueblo, Otero, and Las Animas counties, where warmer, grassier lowlands echo the southern plains that form its core range. Away from that corner it drops out quickly.
Boom, bust, and a shifting edge
Cotton rat records lean heavily on the warm months, a pattern that fits a rat whose populations swing sharply with weather and grass growth. The species is known for rapid boom-and-bust cycles, breeding fast in good years, and its northern limit has crept outward as milder winters let it hold ground it once could not. Colorado sits right on that advancing frontier.
Status in Colorado
NatureServe ranks the hispid cotton rat S4, apparently secure, and it is native to the state. Though rare and local here, it is abundant across the southern United States, and its foothold in Colorado is a genuine part of the state’s fauna rather than a stray occurrence.
Full species profile
