a grassland period may of late have been accelerated by the influence of rabbits.'* 



With the modified conditions brought on in the United States by lumbering, 

 grazing, and agricultural practices, the relations of the native mammals to 

 forest and forage are often fundamentally changed* In some localities the 

 maintenance of a sustained 3rield of forest and forage, or the successful opera- 

 tion of specialized and intensive agricultural enterprises, will ultimately 

 depend in large measure on the solution of problems in the life history and 

 control of various mammals. Unfortunately the significance of mammals (and of 

 vertebrates generally) in these matters has been generally neglected, as a 

 perusal of projects and bibliographies shows. To work out these relations is 

 manifestly impossible without close attention to mammalian life histories. 



Life History of Mammals 



■Die suggestions in this leaflet for studying the life history of mammals 

 are divided so as to be applicable to the individual animal in its youth, maturity, 

 and old age. Habits are known to change considerably at different stages of 

 life, and such a division seems logical and justified by the demands for a 

 better knowledge of the developing mammal. 



After the principal life-history stages of the mammal have been studied, 

 its structure and behavior are scrutinized more closely. Of special interest 

 to the student of life habits are the form of the body as related to habits, 

 special or noteworthy structural developments, and adaptations. Perhaps most 

 of the work of the student of life histories, however, will be devoted to the 

 behavior of the mammal, principally in nature, secondarily in the laboratory. 



Relations of Lower Llammals and Man 



Finally the relations of the lower mammals and man are considered. The 

 means of finding and counting mammals are referred to, and the direct and indirect 

 relationships hinted at. These relationships include the important effects of 

 man*s activities on wild mammals, and, conversely, the effects of the mammalian 

 activities on man*s interests. There is also suggested the possibility of 

 undeveloped mammalian resources, as of new and unrecognized species of game, 

 flesh for food, and fur or hides for clothing. 



SUGGESTED STUDIES 



The points incorporated in the outline that follows are some of those 

 concerning which additional detailed information is desirable. No one person 

 can hope to acquire full information on all the items listed. The suggestions 

 serve as a guide to what should be sought in the course of field work. They 

 should also serve to encourage the recording of many facts that come to the 

 notice of the observer, facts that are not ordinarily recorded because of 

 their supposed unimportance. In general, the main headings alone will adequately 

 serve the purpose of the investigator. In particular instances, however, the 

 details listed under each heading may be found useful. 



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