Rodents of Colorado in ir 

 Economic Relation 



By 



W. L. BURNETT 



Introduction 



The word rodent" is from the Latin word rodo, to gnaw. 

 Rodents constitute the largest order of mammals. In Colorado 

 we have 81 species and subspecies^ divided by families, as follows : 

 Family 



SciURiDAE Tree-squirrels, ground-squirrels, prairie-dogs, 



chipmunks, woodchucks. 



A rodent can always be distinguished from other mammals by 

 its teeth. Rodents have no canines, and only four incisor or front 

 teeth, never more or less. For a number of years the hares and 

 rabbits were classed with the rodents, but they are now in a sepa- 

 rate order known as Lagomorphia. The hares and rabbits have 

 four incisor teeth in the upper jaw, this, with a modification of the 

 movement of the elbow joint, and only a lateral motion to the jaws 

 in chewing serve to separate the two orders. 



In 1910 Warren's Mammals of Colorado was published, and 

 is the best local list of the kind ever published for any state. How- 

 ever, since that time, some changes have been made in Mammalian 

 nomenclature, both in specific and generic names. Some additions 

 have been made in the list of rodents that occur in the State, and 

 some have been dropped from the list. As far as possible these 

 changes have been made in this paper. 



MURIDAE .._ 



Geomyidae 



Heteromyidae. 



Zapodidae 



Erethizontidae 



...Rats, mice, muskrats, etc. 



Pocket-gophers 



Pocket-mice, kangaroo rats 



..Jumping-mice 



Porcupines 



Castoridae 



Beavers 



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