THE LIFE OF MAMMALS 
piece in its mouth and scampered off, returning as soon as we withdrew. 
In fact, they made themselves perfectly at home in camp.” 
All the large Plains gophers (spermophiles) are gregarious, 
and dig extensive burrows so that they are a serious pest to 
both cultivators and grazers, and must be dealt with by poison- 
ing or otherwise. Their most complete biographies have been 
written by Coues* and by Bailey. '* 
Closely related to the ground squirrels are the prairie dogs, — 
a name given by the early French explorers and trappers of 
Prairie the West, more from their cheerful, puppylike 
Dog. actions, I suspect, than from their cry, which could 
hardly be called “barking”; yet Lewis and Clark, who first 
described the animal formally, called it “barking squirrel.” 
It is a denizen of the dry plains east of the Rockies, while two 
or three other species inhabit the mountains, the Utah basin, 
and southward into Mexico. This animal is sometimes con- 
fused towards the north with the larger gray gophers, especially 
the Columbian and Franklin’s, so that we wrongly hear of 
“prairie dogs” on the Canadian plains; it is to be distinguished 
by its slightly larger size, distinctly brownish color, and very 
short tail (two inches), which is flat and black toward the end. 
The prairie dog is about a foot long, and robust, with 
strong limbs and claws. It dwells in colonies, whose perma- 
nent “towns” or burrows, each marked by a hillock of earth 
about the entrance, spread densely over many acres under the 
natural prehistoric conditions, but now sometimes cover hun- 
dreds of square miles. The burrows are deep and extensive, 
and at first go down at a very steep slope to a depth of twelve 
to fifteen feet, when they turn horizontally, and here and there 
branch into chambers, some of which are family rooms, while 
in others fodder is stored, or refuse and dung are deposited. 
The mound about the hole is packed hard, not only by the 
tramping of the animals, but by crowding it down with their 
noses; this hillock prevents water from running into the burrows 
454 
