1918 | Camp: Burrows of the Rodent Aplodontia 531 
The California species of mountain beaver, even in the high 
mountains, are certainly active during the winter. Near Olema, in 
Marin County, Aplodontia rufa phaea has been trapped, at its burrow 
entrances, during the latter part of November. In the Yosemite 
National Park, at elevations of from 6200 to 8600 feet, winter work 
of Aplodontia californica has been observed—young pine, fir and 
cedar trees with the limbs trimmed off up to ten feet above the 
ground and with twigs trimmed from one side of the trunk only, as 
if worked on when the trees were bent down in the snow. Azalea 
Fig. 6. Life study of Aplodontia rufa californica; Lyell Canon, Yosemite 
National Park, California; July 17, 1915. Note the small eye and ear, the white 
spot at base of ear, the shortness of the tail, and the seemingly sluggish general 
apearance of the animal. The matted appearance of the hair on the back is 
due to moisture. 
and other thickly growing bushes with the tops trimmed off evenly 
a foot or more above the ground indicate that the animals probably 
forage on top of the snow. 
ScaroLoGy, SANITATION, AND DRAINAGE 
The faeces are black, about the shape of those of a pocket gopher 
but larger(in Aplodontia rufa phaea, measuring 6 to 7 by 15 to 20 
millimeters) ; the urine is yellow and cloudy. Faeces are rarely seen 
about the burrows; they are probably deposited in some particular 
place underground, but I have never succeeded in discovering any in 
the burrow systems excavated. 
