146 The Mammals of Colorado 
Measurements. — Total length, 23.5 ; tail vert., 7.0 ; hind foot, 3.25. 
Description. — (From a specimen taken at Sulphur Springs, Grand 
County, April 13th): Above the pelage is composed of two kinds 
of hairs, a shorter fine under fur, the basal two thirds of which is 
black, and the terminal third, and also the less numerous longer 
coarser hairs, blackish with yellowish white tips; the effect of the 
FIG. 49. WESTERN wooDCHucK, Marmota flaviventer 
Skull showing dentition, about natural size 
whole combination is a grizzled brownish animal; top of head 
quite black ; a mixed brown, black, and white patch between eye and 
nose; end of nose black; a hght buffy patch beside nose, above 
mouth; cheeks rather grizzled blackish; upper surface of feet 
dark brown or chestnut; flanks paler, more fulvous; chin white; 
rest of under parts a bright chestnut; upper part of tail brown, 
darker on outer two thirds; under part darker, blackish. There is 
much variation in the color of various individuals. Some are 
much darker, some are lighter. In worn pelage they are often much 
redder. 
Distribution. — This species is found mainly in the mountains, 
ranging from timber-line down toward 6,000 feet, the lower limit 
