392 ANIMAL STUDIES 



together select a live-oak tree for their operations. They 

 first bore its bark full of holes, each large enough to hold 

 an acorn. Then into each hole an acorn is thrust (Figs. 

 162 and 163). Only one tree in several square miles may be 

 selected, and when their work is finished all those inter- 

 ested go about their business elsewhere. At irregular in- 

 tervals a lozen or so come back with much clamorous dis- 

 cussion to look at the tree. When the right time comes, 

 they all return, open the acorns one by one, devouring 

 apparently the substance of the nut, and probably also the 

 grubs of beetles which have developed within. When the 

 nuts are ripe, again they return to the same tree and the 

 same process is repeated. In the tree figured this has been 

 noticed each year since 1891. 



305. Self-defence. The instinct of self-defense is even 

 more varied in its manifestations. It may show itself 

 either in the impulse to make war on an intruder or in the 

 desire to flee from its enemies. Among the flesh-eating 

 mammals and birds fierceness of demeanor serves both for 

 the securing of food and for protection against enemies. 

 The stealthy movements of the lion, the skulking habits of 

 the wolf, the sly selfishness of the fox, the blundering good- 

 natured power of the bear, the greediness of the hyena, are 

 all proverbial, and similar traits in the eagle, owl, hawk, 

 and vulture are scarcely less matters of common observa- 

 tion. 



Herbivorous animals, as a rule, make little direct resist- 

 ance to their enemies, depending rather on swiftness of 

 foot, or in some cases on simple insignificance. To the lat- 

 ter cause the abundance of mice and mouse-like rodents 

 may be attributed, for all are the prey of carnivorous beasts 

 and birds, and even snakes. 



Even young animals of any species show great fear of 

 their hereditary enemies. The nestlings in a nest of the 

 American bittern when one week old showed no fear of 

 man, but when two weeks old this fear was very manifest 



