O ECONOMIC MAMMALOGY 



plies for some species, and provision of new cover and food supplies for 

 others; the building of towns and cities and numerous other radical 

 changes in the environment. This has added new complications to the 

 interrelations of organisms. In view of all this, the intelligent under- 

 standing and discussion of economic mammalogy involves not only a 

 knowledge of mammals and their habits, but also a comprehensive 

 knowledge of zoology in general and botany, sound views on eco- 

 nomics and an accurate insight into certain phases of history, politics and 

 legislative principles. 



During the past half-century there has been built up a vast and 

 detailed literature of economic ornithology and much of the informa- 

 tion therein is becoming generally diffused, having been systematized 

 and made available to the public in many bulletins and books, 1 The 

 food of many species has been subjected to minute analyses in order 

 to determine just how useful or harmful they may be. On the other 

 hand, few or none of the mammal species have been subjected to such 

 thorough investigation, and the literature of economic mammalogy, 

 though extensive, is still widely scattered. It consists to a great extent 

 of numerous small circulars, bulletins and articles in technical periodi- 

 cals, concerning a few groups of mammals, and occasional desultory 

 items found here and there in the general literature of mammals, with 

 very little systematic discussion of the economic relation of mammals 

 as a whole. 



It is manifestly impossible in a book of moderate size to set forth in 

 detail or discuss adequately all the facts of such a subject, with its mul- 

 titudinous phases, or even to cite all the publications bearing upon the 

 subject. The best that we can hope to do is to generalize most of the 

 information, adding, in footnotes, many references to the literature 

 from which the reader who wishes to delve more deeply into the sub- 

 ject or any phase thereof may obtain more detailed information. The 

 bibliography and footnotes cannot be made at all complete because of 

 lack of space, but we have in most cases sought to select the publications 

 most readily accessible to or obtainable by American readers. 



Two very important facts must not be overlooked. The first is that 

 while most species of vertebrate animals have certain favorite foods 

 upon which they subsist when obtainable, there are other foods that 

 may be used by them in case of emergency, and when they are hungry 



1 Compare Henderson, The practical value of birds, New York, 1927, and the 

 numerous publications cited therein. 



