4 DEPARTMENT CIRCULAR 59, U. S. DEPT. OF AGRICULTURE. 



DATA THAT ARE IMPORTANT. 



The study of mammalian life-histories opens a field of activity for 

 any sincere student with an enthusiasm for closer acquaintance with 

 wild life. No human being and no book, but nature herself, is the 

 supreme authority in natural history. The beginner may make as 

 important an observation as the veteran investigator. The efforts 

 of all are needed if our fund of information is in any sense to be 

 complete. 



The points incorporated in the list which follows are some of those 

 concerning which additional detailed information is desirable. No 

 one individual can hope to acquire full information on all the items 

 listed. The suggestions have been compiled to serve as a guide to 

 what should be sought in the course of regular field work. They 

 should also serve to encourage the recording of facts which often 

 come to the notice of the observer but which are not ordinarily set 

 down because of their supposed triviality. 



No attempt is made to present a complete catalogue. Several legiti- 

 mate fields of inquiry to which contributions can be made by field 

 workers are omitted entirely; for example, the relation of habits 

 to bodily structure. Almost any one of the suggestions included 

 can be followed up and expanded with pleasure and profit, and will 

 be found to possess a surprising degree of interest and often of prac- 

 tical importance. 



For information regarding known habits of the various mammals, 

 the student is referred to Seton's Life Histories of Northern Ani- 

 mals (1909) and to Nelson's Wild Animals of North America (1918). 



MEANS OF DETECTING PRESENCE OF PARTICULAR SPECIES. 



Tracks, distances between footfalls; 



differences in tracks with different 



speeds or movements of animal. 

 Feces — abundance, shape, size, color, 



composition, place of deposit. 

 Claw marks on trees, logs, or ground. 



HABITAT RELATIONS. 



Tooth marks on wood or bone. 



Wallows, dust baths, beds, forms, 

 nests, shelters, runways, holes, 

 trails, cropped or harvested vegeta- 

 tion. 



Relation of soil, rocks, water, air, cli- 

 mate to habits and distribution. 



Effects of unusual climatic conditions, 

 as storms, floods, and forest fires; 



INTERRELATIONSHIPS OF SPECIES. 



degree and rapidity of recovery from 

 disaster. 

 Relation of animal populations to cli- 

 matic cycles. 



Friends. 



Enemies — times of activity; enemies 

 in youth, middle age, old age. 



Prey — modes of capture. 



Parasitic habits of species with refer- 

 ence to each other. 



Parasites, internal and external. 



Bacteria and disease germs (carriage 

 and transmission of disease to stock 



or to mankind ; species as victims ; 

 decimation of animal populations; 

 periodicity of contagious diseases in 

 animals; degree and rapidity of re- 

 covery ) . 



Adaptations of animals to each other 

 or to plants. 



Competition between species, particu- 

 larly between those closely related. 



