226 NORTH AMERICAN FAUNA [No. 55 



the burrows, the size of woodchuck holes, are in places so numerous 

 and so well hidden under ferns and low tangled vegetation that one 

 traversing the home of a colony is constantly falling into them. 

 Unlike gopher burrows they usually are left open and will readily 

 allow a man to slump in up to the boot top. The burrows often go 

 straight down for a foot or two and strike the main tunnels which 

 extend for long distances underground, and often run through wet 

 ground and springy places or carry small streams of water. 



The animals are mainly nocturnal, generally silent, and very shy, 

 but when caught in traps they fight savagely anything that comes 

 within tHeir reach, biting sticks and jumping at any object that 

 moves near them. Their eyes are small and watery, sometimes milky, 

 and their vision is short and poor. One that the writer caught un- 

 injured in a trap was taken to camp with a firm grasp around the 

 back of its neck and kept all day and part of the night before it 

 escaped. It was extremely vicious when touched and tried to get 

 hold of the captor's hands or feet but succeeded only in biting a hole 

 in his heavy leather boot. It cut strings tied around its neck or to its 

 foot. It was finally caged under a telescope top from which it 

 escaped in the night but not until it had given up a few of its secrets. 

 Several times during the night it made a long quavering cry some- 

 thing like the call of a little owl and several times during the fol- 

 lowing day the same cry was heard from the fern beds back of camp, 

 where it was evidently trying to find its way home. These are the 

 only sounds the writer has ever heard these animals make, and may 

 be the sound called " whistling " by various authors. A quavering 

 whistle would describe it fairly well. They also chatter their teeth 

 at one in a menacing manner and are said sometimes to make a 

 growling sound when caught in a steel trap. 



Ned Dearborn found that after being kept in captivity for several 

 days they lost much of their shyness and could be handled safely 

 with proper care, but were rather deficient in intelligence and affec- 

 tion. T. H. Scheffer found it difficult to keep them alive for more 

 than 10 days or a few weeks at most in captivity, even when supplied 

 with abundance of their favorite foods and with living conditions 

 as nearly normal as possible. Even when caught in box traps they 

 would be found dead in many cases after a few hours of confinement. 



H. E. Anthony kept one for a week, and it became tame enougl 

 to eat from his hand. It swam readily when put in water. 



K. Bruce Horsfall told the writer that in Wahtum Lake, on th< 

 north slope of Mount Hood, the mountain beavers swam out into th( 

 lake and from place to place along the, shores, like muskrats, foi 

 which they were at first mistaken. 



At the lower levels they seem not to hibernate in winter, but ai 

 more or less active under the snow, sometimes coming out on th( 

 snow to cut branches and bushes for food. Near Hood River am 

 Parkdale on the north slope of Mount Hood, G. G. Cantwell, 

 March 1919, found their old tunnels leading 20 feet or more undei 

 the snow, but could not catch any of the animals and thought they 

 might be hibernating. Other records of inactivity in winter may 

 indicate partial hibernation or merely the quiet utilization of food 

 stores in their underground storehouses. The animals are never fat 

 enough to suggest possible hibernation. 





