458 GENERAL ZOOLOGY 



great for arboreal life, or because of geological or geographical 

 changes which compelled the larger Primates to seek the ground 

 for shelter and food. Since Primates long before this event had 

 become widely scattered, only those living in the disturbed region 

 modified their mode of living, with the result that monkeys and 

 apes, the gorilla excepted, surviving in other parts of the world 

 are largely arboreal to this day. The subsequent progress of 

 the human race is undoubtedly the result of this change in 

 habitat, whatever the cause, since an arboreal existence has 

 rather limited possibilities for human development. If the 

 interpretation of the geological record is at all correct, speciali- 

 zation and increase in size without a corresponding development 

 of the brain have spelled disaster for many animals in the past. 

 Man is fortunate in that his specialization has been in the direction 

 of greater brain power while the rest of his body has retained a 

 certain flexibility by remaining relatively unspecialized, a combi- 

 nation which enables Man to make use of past experiences and 

 to suit action to requirement to a greater degree than any other 

 animal. 



