NATURAIv HISTORY SKETCHES 335 



upon the back and head, but bluish slate toward the 

 belly and inside the limbs. The ears are naked, the eyes 

 closed, the tongue exposed and jaws slightly open, no 

 teeth, claws large, tail long for its size. After birth the 

 cub receives but little food and passes the three or four 

 months in semi-torpor and grows but little until the 

 parent emerges, and then quite fast. It is singular that 

 so large an animal, that often weighs four hundred 

 pounds, should have so small cubs. 



In this bear hibernation destroys maternal instinct. 

 She will always leave her cub to freeze when driven 

 from her den ; but in April or May keep away from her. 

 That an animal so highly organized as a bear should be 

 able to retain not only its vitality, but its animal heat 

 and its muscular strength for four months, without any 

 food whatever, is well attested, knowing as we do that 

 in this time, if there be no supply there is no waste save 

 perhaps of animal heat. 



But when we consider the female, we find there is 

 waste and no supply. The material for a second life and 

 its growth must be taken from an accumulated fund. 

 An atmosphere saved only by the animal heat of the 

 mother from that without the den often down to zero and 

 a torpid mother await this blind-born, feeble offspring. 

 By some instinct it is led to the mamma, where, like 

 certain marsupials, it retains a firm hold on the nipple, 

 and now a change comes over the still torpid parent in 

 the increase of the lacteal glands to secrete milk ; and a 

 wonderful fact is that no food is taken by the parent 

 during both operations. And how wonderful the polar 

 bears, whose retreat must be doubled in length and 

 severity by the arctic latitude and ice-formed den. 



