Smithsonian National Museum of Natural History, North American Mammals
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Sigmodon ochrognathus

Yellow-nosed Cotton Rat

Order: Rodentia
Family: Cricetidae

Image of Sigmodon ochrognathus
Sigmodon ochrognathus - lower left (with S. hispidus)
Click to enlarge. (84 kb)

Conservation Status: Least Concern.

Voles and cotton rats usually live in different geographic regions, but both groups of small rodents eat grass and make runways. Yellow-nosed Cotton Rats are especially vole-like because they are small and live in grassy patches of habitat in mountains. They are found on isolated mountains at all elevations, sometimes using surface nests and sometimes building them underground. They have 2-6 young in a litter, at almost any season of the year except during the driest part of the summer. The young nurse for about 15 days, but in just over a week, they are also beginning to eat grass.

Sexual Dimorphism:

Range: 132-264 mm

Range: 51-106 g


Bailey, V., 1902.  Synopsis of the North American species of Sigmodon, p. 115.  Proceedings of the Biological Society of Washington, 15:101-116.


Mammal Species of the World

Mammalian Species, American Society of Mammalogists' species account

Distribution of Sigmodon ochrognathus

Image of Sigmodon ochrognathus
Click to enlarge. (113kb)