INSTINCT AND REASON 245 
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. 
61 and 62). 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 dozen 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. 
132. Self-defense.—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 
fuot, 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 wecks old this fear was very manifest 
17 
