INTRODUCTION Ye hb 
There are other books about the beaver, one of which, 
Morgan’s ‘The American Beaver and His Works,” will 
always be a classic on the subject. Morgan’s studies were 
the first attempt to assemble really accurate information 
as to the habits of the animal, the size and construction of 
its dams, house and other structures, although Hearne 
had contributed a great deal to our knowledge, some of 
which was quoted by Morgan. He wrote, however, al- 
most exclusively about the beavers of the Northern Penin- 
sula of Michigan, and the book was published more than 
fifty years ago. 
Since that time much more has been learned about the 
animal, and a few books published, but as in Morgan’s case, 
treating mainly of the animal as found in a certain region. 
Mills’s ‘‘Beaver World” is on the Longs Peak region, and 
Dugmore’s “‘Romance of the Beaver’ is largely about the 
Canadian and Newfoundland beaver. Both contain much 
valuable information. 
I have given much time to studying the beaver, mostly 
in Colorado and the Yellowstone National Park, as well 
as In such other places as I happened to be and where the 
animal was to be found. In doing this work I secured 
considerable information concerning the beaver’s habits, 
and especially about dams and houses, much of which has 
been published elsewhere. In the course of my studies I 
came to realize that there was no one book about the beaver 
which was as comprehensive in its scope as such a book 
should be, and it seemed to me that such a book was de- 
sirable. Hence the attempt to supply this want. 
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