enced by the available supply of food to which it is 

 accustomed or that is necessary for its require- 

 ments. 



"Examples of this character may be cited 

 among several species of mammals. It is the cus- 

 tom of the chipmunks, or 'ground squirrels,* to 

 hoard up at least a partial supply of food in the 

 autumn for consumption during the winter months; 

 but this is rarely, if ever, sufficient to keep these 

 interesting little animals active for the entire pe- 

 riod. In most localities, there is no available food 

 with which to augment their scant store and they 

 are never in evidence from late October to April. 

 In other locations where the fruit of the Crataegus, 

 or 'thorn apple,' is to be had, they may be seen 

 almost daily, although the ground may be covered 

 with several feet of snow and low temperatures 

 prevail. 



"Another example is the opossum. Ordinarily 

 these animals are active throughout the entire 

 year, but towards the northern edge of their range 

 they frequently hibernate for considerable periods 

 (thirty-one days from personal observations). 



"Certain of the small rodents can, and probably 

 do, hoard sufficient food for actual need during the 



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