Body length – 13 to 18 ½ inches

Weight – 2 to 3 pounds

This chunky, grizzled gray rodent looks a lot like a tailless muskrat . It has a small, one inch furred tail. The fur is course and dull, the eyes are small, and the ears are small and rounded.

The lifespan may reach 5 to 6 years.

Mountain beavers inhabit moist forest habitats with ample vegetative ground cover.

Populations of mountain beavers are found in west central Nevada, northern California, western Oregon, western Washington, and southwestern British Colombia.

Mountain beavers make extensive, shallow burrow and tunnel systems in the ground. They are generally solitary ( except during breeding and when the female is raising her young.) Most of their time is spent on or below ground; however, they will also climb trees and swim. Mountain beavers are active throughout the year. Most activity occurs at night but they will be active throughout the day. Periods of activity tend to alternate with periods of rest. Mountain beavers have archaic kidneys and are not able to concentrate urine. They also are unable to sweat or pant so they require a cool regime and water available at all times.

Mountain beavers are herbivores. They forage mainly on the ground for various types of herbaceous plants , trees and shrubs. Grasses and forbs are dried and stored for winter use. Surface water or succulent vegetation is consumed on a daily basis.

Females are ready to breed at about 2 years of age. An oval nest of leaves, twigs, and grasses is constructed in a chamber located about two feet below the surface of the ground. 2 to 4 young are born in March to April after a gestation period of 28 to 30 days. The young are weaned in about 6 to 8 weeks.

Mountain beavers are state protected in Nevada and are further classified as Sensitive.

The mountain beaver is thought to be the most primitive living rodent.