INTRODUCTION 



Acknowledgments 



To almost everyone who has written upon North American 

 mammals I owe acknowledgment, for I have helped myself 

 liberally wherever I found data. To the authorities of the 

 American Museum of Natural History I am profoundly grate- 

 ful, for without their permission to use collections, library, and 

 other facilities I could not have undertaken this field book. 

 To my colleagues. Dr. Frank M. Chapman and Dr. Frank E. 

 Lutz, I am greatly indebted for advice on various matters 

 which their experience with popular handbooks has quahfied 

 them to give. The members of my own department in the 

 Museum have been of assistance in helping with some of the 

 details which pile up in the work of this sort. The artists 

 whose illustrations appear, Miss Olive Otis for color plates, 

 Mr. Francis B. vShields for line cuts, and Mr. Frank Vitolo for 

 maps, have worked under my direction and done much to 

 relieve a lengthy text. In answer to my appeal for photo- 

 graphs, the naturalists whose work is shown have responded 

 most generously and I am greatly obligated to them for their 

 cooperation. In conclusion, I tender my sincerest thanks to 

 my secretary, Miss Ida Grobe, whose unfailing interest, 

 patience, and diligence have been of the greatest value to me 

 and without whose help the long-suffering publishers would 

 still be calling for copy. 



I know that errors will be discovered in this book. I hope 

 they will not be many. I have striven to keep the number 

 as low as possible and when they do appear I take full credit, 

 or discredit, for them. I shall be glad to have my attention 

 drawn to such errors, not because I shall be pleased to learn 

 of their existence, but because with this knowledge I shall be 

 warned against their repetition. 



