FAMILY ERETHIZONTIDAE 



SUBFAMILY ERETHIZONTIDAE 



Genus Erethizon (Porcupines) 



Form stout, tail short and thick, color blackish or greenish 

 yellow, dorsal and lateral portions of the body, including the upper 

 part of the tail, covered with sharp spines mixed with stiff hairs, 

 ventral portion covered with stiff bristles. Skull thick, nasals 

 long in the Colorado species, incisor teeth large, outer surface 

 orange. 



Colorado Species of Porcupines. 



Yellow-haired Porcupine, Erethizon epixanthum. 



Porcupines are found in Colorado throughout the higher 

 mountain portions of the State. However, every fall, we have 

 a vertical migration of these rodents, and a number invade the 

 plains regions adjacent to the foothills, some falls to a greater 

 extent than others. 



In the fall of 1915 this migration was very general in the 

 Fort Collins district. Two were seen on the college ca?npu:;, two 

 were killed in the business section, and a number were reported 

 from the country. 



Porcupines feed upon the bark of trees and upon grass and 

 vegetables. The only damage reported to us is that of destroying 

 standing timber by barking the trees. 



FAMILY SCIURIDAE 

 Among the members of this family are found our worst mam- 

 malian pests, prairie-rogs and ground-squirrels. The members of 

 this family vary much in size, from the active little chipmunk to 

 the slow, easy-going woodchuck. Other members of this family are 

 the pine-squirrel, and tuft-eared squirrel, the handsomest and most 

 graceful of all our rodents. Some live in burrows out on the 

 treeless prairies, where they build nests in these undergrown bur- 

 rows for their young, others occupy the same relative position in 

 the mountain meadows, and still others live among the rocks and 

 trees. 



Genus Marmot a 

 Form stout, tail medium short, a patch on chin and between 

 eye and nose white, cheek pouches small. Total length about 

 23 inches. Inhabiting the mountainous portions of the state from 

 between 6,000 and 7,000 feet elevation up to timber-line. The low- 

 est elevation we have a record of is 6,700 feet. 



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