morning, emit whistling sounds similar to those of the prairie dog 
(Cynomys ludocicianus). Lord (1866) heard whistling in the evening 
which he attributed to the mountain beaver. Matteson (1877) said the 
rodent made a booming noise. Lum (1878) said it growled when caught 
in a trap. Anthony (1916) stated that angry mountain beaver utter a 
husky querulous note somewhat like a cough. Scheffer (1929) wrote: 
"The whistling sounds credited to them by careless observers 
can be traced to other sources, probably to the sooty grouse 
(Dendragapus obscurus) in one case and to the marmots of the 
Cascades and the Olympics in the other," 
Kindschy and Larrison (1961) wrote that a mountain beaver captured 
in a trap and presumably in pain, uttered a soft whining and sobbing 
sound, Wendell E. Dodge (personal communication) said that mountain 
beavers emit a high-pitched squeal when fighting with each other in pens, 
but never heard them make noises when not disturbed. 
Perception 
Due to its fossorial habits, the mountain beaver'’s sight and PREUE 
are limited. Camp (1918) wrote: 
"Sight and hearing seem to be relatively defective in the 
mountain beaver. The individual comes in contact with its 
underground environment chiefly through the sense of feeling, 
and this is markedly developed all over the body. The 
slightest touch upon a hair will be responded to instantly 
by quick jerking movements. The sense of smell seems to be 
good, for the animal has a way of frequently raising its 
nose to sniff; also the scent glands are well developed." 
™, 
Scheffer (1929) wrote: 
"They readily leave their burrows in the twilight of evening 
to follow a trail of apple peelings or other tempting bait. 
Judging from observation of their mode of life, it is probable 
that the sense of smell plays but little part in enabling them 
to detect the presence of an enemy. On the other hand, it is 
no doubt their chief means of recognizing their kind, for they 
possess an unmistakable body odor, though it is not so pro- 
nounced as in the case of the Mustelidae, including martens, 
weasels, otters, and skunks." 
Sociability 
The mountain beaver is not sociable. Anthony (1916) stated that 
although it has been asserted that the mountain beaver is gregarious and 
lives in colonies of several individuals, this he thought to be a few 
individuals. Scheffer (1929) found no evidence that the animal possessed 
any social traits. He wrote; 
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