150 The Mammals of Colorado 
Cynomys ludovicianus (Lat., of or from Louisiana). 
Plains Prairie Dog. 
Arctontys ludovicianus Ord, Guthrie's Geog., 2d. Amer. ed., p. 
292 (1817). 
Type locality. — Plains of the Upper Missouri. 
Measurements. — Total length, 14.25; tail vert., 3.0; hind foot, 
2-35- 
Description. — (From a specimen taken near Colorado Springs 
Sept. 8th) : Reddish brown above, brightest and clearest on shoulders 
and top of head; on back and rump somewhat grizzled with black 
and white hairs; flanks paler, sides of head and body, upper surfaces 
of feet, lighter, more yellowish ; underparts yellowish white ; basal 
two thirds of tail like shoulders, apical one third black; soles black. 
Spring specimens in the worn winter pelage are somewhat paler. 
Distribution. — The Plains Prairie Dog is found throughout the 
Great Plains from the northern limit of the United States southwards 
to western Texas, east of the foot-hills of the Rocky Mountains. 
In Colorado it is found in every county from the base of the moun- 
tains to the eastern boundary of the State and in many places is 
exceedingly common. 
Habits. — The Prairie Dog is a notably social burrowing 
animal, living in communities called dog-towns, of varying 
extent, sometimes covering many square miles. Vernon 
Bailey states that in western Texas, just to the east of the 
Staked Plains, there is an area 250 by 100 miles in extent 
which is one vast dog-to w^n. This area of 25,000 square 
miles he estimates to contain at least 400 million Prairie Dogs. 
The animals are strictly diurnal in their habits, coming 
out of their burrows at sunrise and disappearing at sunset. 
In warm weather they are not seen much during the middle of 
the day, while in cold weather they prefer the middle portion 
of the day for their outdoor exercise. They spend their 
time outside in feeding, working at their burrows, visiting their 
neighbors, and basking and sleeping in the sun. Each 
burrow is usually protected by a crater-like mound, which 
prevents the ingress of water. The food consists almost 
entirely of grass, — roots, stems, and blades, — though other 
