ANIMAL BEHAVIOR 



By Ernest P. Walked ^ 

 Assistant Director, United States National Zoological Park 



[With 18 plates] 

 INTRODUCTION 



The everyday life of an animal is a struggle to avoid enemies, to 

 obtain food and shelter, and to reproduce. A single incident of 

 carelessness or ineptitude may result fatally. Hence, in a long proc- 

 ess of evolution, every surviving animal species has developed pro- 

 nounced traits, characters, or reactions adapted to help the creature 

 meet the daily conditions of its life. 



The problems of life for all wild animals fall into a few general 

 categories not greatly different from those that confront us. In 

 self-preservation all but a few of the most powerful creatures must 

 be prepared to avoid other animals by fleeing or by concealment, or to 

 fight them off or deter them in some manner. All must be proficient 

 in obtaining food; and, since the food supply of many kinds is not 

 uniform throughout the year such creatures must either (1) store 

 up their winter's supply, (2) go where a sufficient supply of food 

 is obtainable, or (3) make use of the provisions with which nature 

 may have equipped them for storing up reserve energy or for 

 hibernating. Those that live in damp regions ordinarily have no 

 difficulty in obtaining sufficient water whenever they need it. Others 

 must be able to endure long periods without an opportunity to drink. 

 To the great majority of animals a home of some sort is essential. 

 For homes they either use natural shelters or construct or excavate 

 shelters to their liking. All animals have their social problems — 

 whether to live amicably together in communities or to live singly. 

 Some have developed cooperation to a high degree and many recog- 

 nize the property and territorial rights of others. Voice and com- 

 munication among animals are much more generally prevalent than 

 is ordinarily supposed. The means by which animals get about are 

 varied in adaptation to the lives that different creatures lead. The 



^The writer wishes to express his gratitude to Messrs. Gerrit S. Miller, Jr., and Vernon 

 Bailey for advice and suggestions during the preparation of this paper. 



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