On Hybernation, 75 



ZOOLOGY. 



Art. XIII. — On Hybernation fhy Isaac Lea of Philadel- 

 phia. 



This is a subject that has excited much and peculiar in- 

 terest. My object is not to enter into the minutiae of the 

 subject but to take a general view and relate some of the 

 most interesting facts which I have been able to collect with 

 regard to it. 



There may be said to be four species of hybernation — i. e. 

 in the case of those animals that change their covering — of 

 those that lay up food — of those that migrate, and of those 

 that remain torpid during the winter months. 



Dr. Reeve has described hybernation as a continu- 

 ance of life under the appearance of death, a loss of 

 sensibility, and of voluntary motion, a suspension of 

 those functions most essential to the preservation of the an- 

 imal economy; " these constitute," he continues, one of the 

 most singular problems in the whole range of natural phi- 

 losophy." 



When we look upon this subject with a philosophic eye, 

 the mind is struck with astonishment at the wonderful com- 

 pensation made those animals which have not the power of 

 locomotion, and which are so situated as to be deprived of 

 food by the approach of severe cold. Their adaptation to 

 this situation, is beyond the power of the human mind to 

 explain, as we find so many cases vi^hich seem to prove an 

 opposite principle. It would appear from the general idea 

 we have of the subject that cold was a necessary cause to 

 induce this state; but this is not always the case. The 

 Tanric Caudatus, an inhabitant of India and Madagascar, 

 becomes torpid and continues so nearly six months. The 

 Dipus Sagitta is equally torpid in Siberia and in Egypt; 

 but nature is not always true in this respect, for we are told 

 by Dr. Barton that many animals that become torpid jn 

 Pennsylvania are not so in the Caroiinas, so that this re- 



