REFLEXES, INSTINCT, AND REASON 



437 



or hibernates till spring. In some cases the climatic instinct 

 merges in the homing instinct and the instinct of reproduction. 

 When the birds move north in the spring they sing, mate, 



* t: '- ^y*'--' 



and build their nests. The fur seal goes home to rear its young. 

 The bear exchanges its bed for its lair, and its first business 

 after waking is to make ready to rear its young. 

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