The mountain-beaver lives a monotonous existence and correspondingly lacks the mental vivacity of many other species which have a greater freedom of movement. When one is caught it shows little fear, but struggles to escape, growling, clattering its teeth, and biting viciously at anything within reach. Its desire for food, however, appears to control its emotions, and very soon after being captured it will eat any green vegetation offered, as unconcernedly as though free. That the mountain-beaver possesses social instincts is evident, as a pair is often found occupying one set of tunnels, and in many favorable places a number will have their burrows closely grouped and connected with a network of communicating surface trails. Although mainly nocturnal, the animals are active early in the morning and late in the afternoon, as well as throughout dark days. Those kept in captivity would show periods of restless activity at night and have alternating periods of sleep and wakefulness during the day. Sometimes they would sleep coiled with the head turned under the body and again flat on their backs. During these periods their sleep is often so profound that they may be handled without being awakened. One captive animal is reported to have uttered a curious quavering note resembling that of a screech-owl. They have a strong musky odor, which is very evident when they are first caught, and which is frequently apparent about the burrows. Careful and repeated efforts to keep these animals in captivity under as near normal conditions as possible in regard to food and surroundings in the vicinity of where they were captured have, up to the present time, resulted in failure. In every case the animals failed to thrive and soon died. The mating occurs about the middle of March, and a month later litters of two or three young are born. The young grow slowly, not attaining full size for a year or more, and do not breed until the second year, but they leave the shelter of the home nest and scatter to occupy burrows of their own at the end of the first two or three months. The mountain-beaver feeds upon nearly all small vegetation growing in its haunts, including, in addition to small herbage, shrubs, the bark of trees and bushes, ferns, and fern roots. More than thirty species of native plants have been found among its “hay” piles at the mouths of burrows. Since its country has become increasingly occupied by farmers, it has developed a fondness for cultivated crops that, in many places, is rendering it a pest. It appears to have a special taste for cabbage, potato, and onion tops, and other garden produce.