STUDIES OF MAMMALIAN LIFE HISTORIES q 
C. Animal surroundings. 
(1) The mammal and its animal associates—in air, soil, water, trees, 
or on land; in burrows, dens, shelters, nests, trails, about water 
holes, salt licks, stamping grounds, or elsewhere. 
(2) Relation of the mamma! and other animals—relation to others of 
same kind, to friends, partners, parasites, prey; competition and 
adaptation among animals; symbiosis, commensalism, warfare, as 
illustrated among mammals and their associates. 
(3) Animal-caused disease—effects ; infection and transmiss‘on to other 
wild mammals, domestic animals, or man. 
(4) Relation of the individual mammal to the development of the com- 
munity. 
INFLUENCE ON ENVIRONMENT 
A. On physical surroundings. 
(1) Incorporation in soil of organic animal materials—such as skin, 
hair, bones, antlers, horns, other organic materials, feces, urine. 
(2) Digging—formation of tunnels, holes, hollows, mounds; burial of 
rocks, logs, grass, or other objects by excavated materials; extent 
of cultivation of soil, the plowing effect of burrowing mammals; 
reduction of ditch banks, stream banks, or other topographic 
features by burrowing; general effects on erosion, beneficial, neu- 
tral, harmful; dimensions of tunnels and chambers, volume of 
earth removed. 
(3) Packing of soil by tramping or trail making. 
(4) Dam building and flooding of valleys. 
(5) Collection of materials for nests, with subsequent decay and soil 
building. g 
(6) Effects on the soil of dissemination, planting, or removal of vege- 
tation by mammals and of burying fertilizing materials. 
B. On plant cover. 
(1) Use of miscellaneous plant parts, as grass, stems, roots, leaves, 
twigs, or seeds for food, shelter, or nests—mammal-caused zones 
of vegetation about burrows, water holes, and other areas of con- 
centration; activities of mammals in gnawing bark and eating 
cambium, girdling trees, peeling bark from trunk or branches, or 
cutting down plants or trees. 
(2) Dissemination, planting, or covering of vegetation by mammals. 
C. On animals. 
(1) Capture and eating of prey—eggs, young, or adults of birds and 
reptiles; young or adults of mammals; of insects, fishes, mollusks, 
crustaceans, and other groups. 
(2) Scattering of parasites or associated species. 
(3) Removal of vegetation—which often profoundly affects the other 
members of the community through disturbing their food and 
shelter relations. 
LIFE HISTORY 
(1) Birth—date, manner, and place of birth; weight of young and 
parents. 
(2) Number of young in a single litter; number of litters a year. 
(8) Structure and behavior—adaptation to protection and survival. 
(4) Growth—stage of development at birth; appearance of the skin, 
eyes, teeth, hair; senses; manner and rapidity of growth; date 
weaned; date of leaving nest; earliest age at which young are 
capable of survival without parents; date of achieving mature 
growth; age of sexual maturity; date of breeding. 
(5) Parental relations—condition and habits of young at birth as re- 
lated to habits of parents; modes of feeding, carrying, and pro- 
tecting young; mannex of keeping young warm: special habits and 
instincts related to care of young; maladaptations in behavior to- 
ward young, as smothering or eating them; attitude of males 
toward young. 
(6) Enemies of young—severe weather and other physical phenomena; 
plant and animal enemies; diseases. parasites, insects, rivals, 
competitors; modes of opposing and escaping enemies; mortality 
rate of young. 
