Pelage 
The pelage looks like that of an unprimed rabbit, but coarser in 
texture due to the large number of interspersed guard hairs. These 
guard hairs are more noticeable on the limbs and ventral side of the 
body. The scattered guard hairs on the dorsal and lateral surfaces are 
black, giving an ochraceous sheen to the reddish-brown underfur. The 
guard hairs on the lower lateral and central sides of the body are almost 
colorless. They appear black at the base but white-tipped, giving a 
smoke-gray cast to these parts. Both sexes have similar pelage color, 
The pelage of the young has less red and more gray. At the base of the 
ear is a conspicuous white spot. 
The mammae number three pairs: The pectoral (just anterior to the 
axilla), the thoracic, and the abdominal. 
Molt 
The only known reference to molt is in Taylor's revision (1918). 
He wrote: 
"There is but one molt annually in Aplodontia. Pelage renewal 
begins in July and August, rarely as early as June, and contin- 
ues for two or three months. There is no hard and fast manner 
of molting. The hair usually begins coming in on the sides 
posteriorly and on the back of the head and neck about the same 
time. From these centers the molt spreads until the new pelage 
covers the body, the hair of the shoulders and rump being the 
last to be renewed dorsally. In some examples the molt proceeds 
somewhat irregularly. The molt of the underparts lags behind 
that of the upperparts, The new pelage is longer and sometimes 
slightly different in coloration from the worn pelage it re- 
placed, Thus in Aplodontia rufa pacifica, the fresh pelage is 
more richly colored than the worn pelage; in A. r. californica, 
it is a trifle browner; and in A. r. phaea, it is a little more 
intensely colored. Differences in coloration and general appear- 
ance are small, however, and in several forms of Aplodontia, as 
at present represented in collections examined, cannot be shown 
to exist at all," 
Abnormal Colors 
Jewett (1935) reported a distinctly albino mountain beaver from 
Yacolt, Wash.; a partial albino from Chelan County, Wash., and a melanistic 
specimen from Clackamas County, Oreg. Anderson and Russell (1957) cited a 
partially albino specimen from King County, Wash. The only two abnormally 
colored mountain beaver specimens in the National Museum are No. 30889, a 
partially albino adult male collected by C. P. Streator on September 14, 
1891, at Sauk, Wash., and No. 192635, a melanistic adult male collected by 
C. A. Allen on August 2, 1886, at Point Reyes, Calif. 
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