5290 TORPIDITY OF ANIMALS. 



instance o the migration of insects. Indeed, if we except 

 bees, wasps, ants, and a few others, most insects, whether 

 they inhabit the air, the earth, or the waters, are perfect wan- 

 derers, having no fixed place of residence. Some of them, 

 as the spider tribes, build temporary apartments; but when 

 disturbed, they migrate to another commodious place, and 

 erect new habitations. 



From the facts which have been enumerated, it is apparent 

 that the principle of migration, or the desire of changing 

 situations, is not confined to particular birds, but extends 

 through almost the whole system of animation. Men, quad- 

 rupeds, birds, fishes, reptiles, insects, all afford striking exam- 

 ples of the migrating principle. From the same facts it is 

 equally apparent, that the general motives for migrating are 

 similar in every class of animals. Food, multiplication of the 

 species, and a comfortable temperature of air are evidently the 

 chief causes which induce animals to remove from one place to 

 another, or, what amounts to the same thing, from one climate 

 to another. Partial emigrations, or emigrations to small dis- 

 tances, are prompted by the same instinctive motives which 

 induce animals of a different structure to undertake long and 

 fatiguing excursions. But previous to actual migration, what 

 are the peculiar feelings of different animals, and what should 

 stimulate them to proceed uniformly in the direction that 

 ultimately leads them to the situations most accommodated to 

 their wants and their constitutions, are mysteries, with regard 

 to which, like every other part of the economy of nature, it is 

 the duty of philosophers, instead of attempting to push their 

 inquiries beyond the bounds of human ability, to observe a 

 respectful silence. 



The third method by which animals are enabled to avoid 

 suffering from the winters of cold climates, is by passing them 

 in a state of TORPIDITY. Among quadrupeds those which 

 become torpid are found in the orders Carnivora and Roden- 

 tia ; as the bat, hedge-hog, tenrec, marmot, hamster, dor- 

 mouse, &/c. They pass into the state of torpidity at different 

 times of the year, according to the severity of the climate 

 they inhabit. Thus in Canada the jerboa goes into winter 

 quarters in September and comes out in May, but in England 

 torpid animals usually retire in October and reappear in April. 

 The place in which they pass the winter is that which they 

 have been accustomed to inhabit during the summer. The 

 bats retire to caves and old chimneys, where they remain sus- 

 pended by the claws. The marmot, hamster, &/c., secure 



