AISriMAL BEHAVIOR — WALKER 301 



of this genus [Phrynosoma) lay eggs and others produce living 

 young. In few cases, however, is there evidence that reptilian 

 parents give their young care. 



Some insects that do not actively care for their young after they 

 have hatched make elaborate advance provision of food for the 

 young that they will never see, and some, like the wasps and bees, 

 have elaborate colony systems in which certain castes devote their 

 time entirely to the care of the young. 



Every animal that cares for its young has developed methods 

 characteristically its own. Innumerable examples might be cited, 

 did space permit. 



LIFE WITHIN THE HOME 



Naturally the life of an animal within its home is as specialized as 

 are its activities outside. For example, the burrow of the pocket 

 mouse is scarcely wider than the diameter of the animal's body. One 

 may well wonder how it is possible to turn about in one of them; 

 but my little pet showed me how this is done. I found that when 

 he wanted to reverse his direction and the burrow was too small 

 to allow him to turn in it, he tucked his head backward beneath his 

 body and practically revolved on himself like a ball. This brought 

 him wrongside up; but, too quickly for the eye to see the detail of 

 his movements, he would roll over and be ready to go in the opposite 

 direction. 



The tunnel of the mole is only slightly greater in diameter than 

 the body of the animal. Therefore, turning about would be a prob- 

 lem, particularly as the forward two-thirds of the mole's body is 

 extremely rigid and muscular. To avoid turning around the mole 

 merely runs backward in his burrow. This he can do about as fast 

 as he can go forward. If the mole's fur were even fairly stiff and 

 its hairs were directed backward, it would impede the animal's back- 

 ward progression; but it is very short with the hairs standing at 

 right angles to the skin so that they will lie smoothly when pointing 

 either forward or backward. 



In their nest chamber beavers groom themselves, eat the pieces 

 of wood that they carry up into the houses through the tmmels, sleep, 

 raise their young, and remain secure from enemies. 



CLEANLINESS AND CARE OF THE BODY COVERING 



Human beings replenish their wardrobes as required or as their 

 means permit. Animals, however, are limited to definite times for 

 gettmg their new suits of clothes. Usually they grow a heavy 

 coat with the approach of winter. Tliis coat lasts them until spring, 

 by which time it has become considerably worn. It is then shed 



