PRAIRIE-DOGS 155 
‘‘prairie-dogs’’ on the Canadian plains; it is to 
be distinguished by its slightly larger size, dis- 
tinctly 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 permanent ‘‘towns’’ of bur- 
rows, each marked by a hillock of earth about 
the entrance, spread densely over many acres 
under the natural prehistoric conditions, but 
“now sometimes cover hundreds 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 hori- 
zontally, and here and there branch into cham- 
bers, 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 when the plain is flooded by 
heavy rains. and also serves as a tower of ob- 
servation. 
