148 The Mammals of Colorado 
especially of lying stretched out upon some rock which 
commands a view of their surroundings. Their food is ex- 
clusively vegetable, consisting of the grass and other plants 
growing near their homes. We have never heard any 
complaints of this species doing any damage to farm crops, 
such as are often made against the eastern form, though we 
have several times found it on ranches in close proximity 
to cultivated fields. In one way, however, it is sometimes 
considerable of a nuisance, and that is by entering vacant 
cabins and houses in the mountains, and gnawing the wood- 
work of the floors and walls, and any furniture which may be 
there. Sometimes quite a little damage is thus done, to say 
nothing of the dirt and debris the animals leave about. 
Not very much is known of their breeding habits. Young 
a fourth to a third grown are seen about the holes early in 
July, or even late June. A female, taken at Sulphur Springs, 
Grand County, May 4th, contained eight embryos. 
The Woodchuck hibernates, retiring early in autumn, 
usually, in Gunnison County at least, about the first of 
October, though individuals may sometimes be seen about 
much later than this, and even when the snow is quite deep. 
The date of their appearance in spring varies, being no doubt 
dependent on two things, the altitude at which the animal 
is living, which affects the depth of snow and the lateness of 
its staying, and also on the season, whether late or early. 
They are likely to come out of winter quarters any time in the 
early part of April. 
Genus CYNOMYS (Grk. kun, dog, + mus, mouse, literally dog- 
mouse). 
Cynomy s Raiinesqne, Amer. Month. Mag., ii., p. 45 (1817). Type 
C. ludovicianiis . 
Stout, thickset, terrestrial and burrowing animals with rudimen- 
tary ears and short tails; cheek pouches shallow; fore and hind 
limbs with five clawed digits; skull heavily built with stout decurved 
