INTROD 



THIS bulletin on the small mammals of Colorado omits all mention of 

 the tree squirrels, ground squirrels, chipmunks, and gophers, which 

 were excellently treated by Mr. Robert Rockwell in his bulletin on those 

 animals. The present paper aims to give some mention of our smaller 

 mammals, though it has been a little difficult at times to tell where to 

 draw the line, and what to include and what to omit. Many of these ani- 

 mals are but little known to the casual observer, largely because of the 

 nocturnal habits of the majority of the species, and the retiring habits of 

 others. When one becomes acquainted with them and their ways he finds 

 them very interesting, and their life histories well worth studying. In 

 fact there is still much to be learned about many of them. 



Since the writer's "The Mammals of Colorado" was published, some 

 ten years ago, a number of the genera of North American mammals have 

 been studied by specialists, with the result that some species and sub- 

 species have been added to and others dropped from our local list, and 

 some of the scientific names have been changed. While not making the 

 latter especially prominent in the text, they have invariably been given, 

 for they are a more positive identification of the species than any English 

 or vernacular names. No detailed descriptions of any of the species are 

 included, only a general idea of the color and size is given. The total 

 length is from the end of the nose to the end of the tail, measured in a 

 straight line when the animal is stretched out, and the tail is measured 

 from the root to the tip. 



I have omitted all mention of the bats, although a considerable number 

 of species is found in the State. These belong to so many different genera 

 that a general description of the animals would be very unsatisfactory, and 

 a detailed account is somewhat beyond the scope of this paper. 



For interesting and authoritative accounts of the habits of many of 

 our small mammals I would refer my readers to "The Wild Animals of 

 North America," by E. W. Nelson, Chief of the U. S. Biological Survey, 

 published by the National Geographic Society. Mr. Nelson's opportunities 

 of observing the habits of many of our species have been remarkable, and 

 he has made much use of the work of other naturalists. 



In giving scientific names, when the name of a genus is repeated it is 

 not given in full but abbreviated to the initial letter; likewise in the case 

 of repetition of specific names. 



Unless otherwise mentioned, the illustrations are from my own photo- 

 graphs. Nos. 1, 2, 3, 4, 6, 7, 8, 10, 11, 13, 14, 15, 16, 18 and 20 were 

 originally published in the "Mammals of Colorado" and are printed from 

 the cuts used in that book. For several of the illustrations which have not 

 hitherto been published, I wish to acknowledge my indebtedness to Mr. 

 Charles Mace, Mr. Clark Blickensderfer, Mr. Albert Haanstad, and the 

 Colorado Agricultural College through Mr. W. L. Burnett. 



The pictures will doubtless be of as much use as the text In showing 

 what the animals are like. E. R. W. 



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