Nature's great scheme of balance may be learned from observation of the 

 wild animals of the forests. Man has just begun to study these relations. 

 Nature undisturbed maintains an almost perfect balance between the num- 

 ber of wild animals and the available food. When man removes all such 

 animals as the coyote, wolf, lynx, and wildcat, or such birds as the hawks 

 and owls, nature's balance is upset. Such creatures normally prey on other 

 animals for food and thereby keep them from overpopulating a given area. 

 The weaker, slower, and less alert animals are first captured, leaving the 

 stronger, more agile, and alert to carry on the race, and insuring a better 

 stock than if the number of undesirables were not reduced. 



The impact of civilization on natural conditions disturbs the original 

 balance. Man uses the forests to maintain his institutions. Under mod- 

 ern conditions, therefore, there is no natural balance and in a general way 



Figure 14. — What habits make a forest home necessary for the beaver, (/4), and the bear (B)? 



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