CHAPTER VIII 



PHYSIOLOGICAL EFFECTS PRODUCED 

 BY AGGREGATIONS 



C 



OLLECTiONS of animals 

 into apparently unorganized crowds have been 

 recorded for years, particularly in connection 

 with breeding activities of otherwise solitary 

 animals or with their hibernation. At times of 

 drought great numbers of animals collect about 

 favorable water holes, or they may collect in 

 regions where food is plentiful or where shelter is 

 abundant. Similarly for years it has been well 

 known that many animals collect into closely 

 organized flocks or herds which are able to pro- 

 tect themselves by the results of their social 

 activities, either by structures they build to- 

 gether, as in the case of beaver dams, or by the 

 protection furnished by multiplicity of eyes or of 

 voices to give warning of danger, or of beaks, 

 claws, teeth and hooves, to furnish active pro- 

 tection from enemies. 



Little or no connection was thought to exist 

 between the two sorts of aggregations because, 

 breeding season aside, crowding has been dem- 



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