Keen's Deermouse is the most common deermouse in the Pacific Northwest. It inhabits rainy, mild climate zones at higher elevations than the closely-related Deermouse (Peromyscus maniculatus), and prefers areas where the forest canopy is...

Osgood's Mouse is a very close relative of the Pinyon Mouse but is larger, and its tail is longer than the head and body. Osgood's Mouse lives in the mountains of southern New Mexico and throughout mountainous central Mexico. Learn more...

Southwestern myotis live in a variety of southwestern mountain habitats, from desert grasslands up into pine and mixed coniferous forest in the United States, and in desert and grassland in Mexico. These bats and two other myotis...

Although the northern long-eared myotis is common and widespread, much remains to be learned about its roosting habits, reproduction, and longevity. This bat is known to hibernate in caves and mines and to roost under tree bark. Learn...

A small fold, or "pocket" in the wing membrane of the free-tailed bat, near its knee, gives this bat its common name. Pocketed free-tailed bats have large ears and long wings, and fly rapidly, generally pursuing insects on the wing....

Marsh rice rats are among the most common mammals inhabiting tidal marshes of the Gulf and Atlantic coasts. Being good swimmers, diving to 10 m and crossing 300 m stretches of water, and able climbers, these rice rats are suitably...

Pinyon Deermice reproduce from mid-February through mid-November, giving birth to litters of 3-6 blind, hairless young that weigh about 2.3 g each. Learn more about the Peromyscus truei, more commonly known as a Pinyon Mouse, in this...

Oldfield Mice inhabit areas with loamy or sandy soils in the southeastern United States. Newly abandoned fields, where plants such as crabgrass are sprouting, provide good habitat. Learn more about the Peromyscus polionotus, more...

Pygmy Rabbits dig extensive burrow systems, which are also used by other animals. Loss of habitat is a direct threat to this species, which depends on big sagebrush, particularly mature stands of it. Learn more about the Brachylagus...

Plains Harvest Mice are found in grassy areas, including hay and wheat fields. They seem to prefer shorter grasses, and build round nests of grass on or near the ground. Learn more about the Reithrodontomys montanus, more commonly known...

Salt-marsh Harvest Mice have a very limited range, they live only in San Francisco Bay's tidal marshes and diked salt marshes and they have very specific habitat requirements. They need dense cover. Learn more about the Reithrodontomys...

Western Harvest Mice are adaptable, widespread, and abundant, especially in meadows, prairies, old pastures, stream valleys, and marshes. They eat seeds, insects, and plants. Learn more about the Reithrodontomys megalotis, more commonly...

The largest moles in North America, weighing in at 100 - 171 grams, Townsend's Moles live only in the lowlands on the western side of the Cascade Mountains, from northwestern California to extreme southwestern British Columbia. One...

Open, rolling land and gentle slopes with shrubs are the habitat of Nelson's Antelope Squirrel, which lives only in a small region of California in and near the San Joaquin Valley. The squirrels live in relatively small colonies of six...

Mexican Fox Squirrels are large but secretive, and though they spend much of their time on the ground, can be difficult to find at any season. They do not store food or bury nuts. Learn more about the Sciurus nayaritensis, more commonly...

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...