Chap. 37 



MAMMALS AND MANKIND 



753 



FLYING 



^MlNG^mD^ 



i 



Fig. 37.1. The spread of mammals in environments and habits. Mammals prob- 

 ably first lived in trees, climbing and leaping. From there they gradually radiated 

 into other habitats and activities. (Courtesy, American Museum of Natural His- 

 tory.) 



mammals accounts such as Movement and Muscles (Chap. 10), Foods and 

 Nutrition (Chap. 11), and The Release of Energy — Respiration (Chap. 13) 

 and others should be consulted. These are units of The Internal Environment 

 of the Body discussed in Part 3. 



The Domestic Cat — A Representative Mammal 



The cat is regularly studied as a mammal and an introduction to the human 

 body. The discussions of organs and systems in Part 3 were prepared with 

 those two ends in view, especially the latter. It will be of help and interest if 

 they are consulted as suggested. 



The study of organs should always be lifted by acquaintance with the grace 

 of the living animal (Figs. 10.1, 37.4). A cat is a natural carnivore and 



