THE PRAIRIE DOG OF THE GREAT PLAINS. 
By 0. Hart MerriAxM, 
Chief of Division of Biological Survey. 
INTRODUCTION. 
In crossing the United States b}^ an}^ of the transcontinental railways 
the traveler who looks out from the car window on the second da}^ west- 
ward from Chicago is sure to have his attention arrested by colonies of 
small animals about the size of cottontail rabbits. These animals are 
prairie dogs. Some stand erect at the mouths of their burrows, view- 
FiG. 24.— Distribution of plains prairie dog {Ci/nomys ludoriciaiius): The occupied area is marked with 
dots. 
ing the passing train; others are engaged in feeding or running to and 
fro about the colony. The land the}^ occup}^ is the broad expanse of 
level and slightly rolling semidesert country known as the (ireat 
Plains, a vast tract which stretches from the Rocky Mountains easterly 
to the western edge of the Mississippi Valle}^ and from Montana and 
North Dakota southward to Texas and Mexico. (See lig. 24.) The 
plains are treeless, except along the streams, and the ground is sparsely 
covered with grass and other small plants, which are green in early 
spring and brown the greater part of the year. 
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