9 2 



Scientific Proceedings (48). 



66 (675) 



The food factor in hibernation. (Preliminary communication.) 



By SUTHERLAND SIMPSON. 



[From the Physiological Laboratory, Medical College, Cornell 

 University, Ithaca, N. Y.] 



In those animals that hibernate the condition is generally 

 believed to be brought about mainly by a low external temperature ; 

 when the winter cold sets in the animal retires to its burrow or nest 

 and remains dormant until spring. Some, on the other hand, hold 

 that a diminished food supply is the chief, or at any rate, an im- 

 portant cause of hibernation, and my experience with a colony of 

 woodchucks (Marmotta monax) during the past winter would ap- 

 pear to support the latter view. 



About the middle of September, 191 1, eighteen woodchucks, 

 which had been caught in box traps in the neighborhood of Ithaca, 

 and were uninjured, were placed in eight artificial burrows about 

 five feet below the surface of the ground, the object being to study, 

 amongst other things, changes in the nervous system during 

 hibernation. The burrows, which were packed with dry straw, 

 opened into a central court into which food (clover, corn, apples, 

 carrots, etc.) was placed every second day, and it was expected 

 that when the animals began to hibernate the food would cease 

 to be consumed. 



In this locality I was told that woodchucks are rarely seen in 

 the open fields later than the first or second week of October, and 

 as the food still continued to disappear after that time, the burrows 

 were opened up and the animals caught and examined to find out 

 their condition, on the following dates. — Oct. 13, Nov. 11 and 27, 

 Dec. 18 and 26. They were found to be quite active on all these 

 occasions, with rectal temperatures somewhere in the neighbor- 

 hood of ioo° F. 



The weather up till the end of December had been unusually 

 mild for this climate, and this might possibly have had some 

 influence in maintaining the wakeful condition, but from the 

 beginning of January till the end of March the winter was exces- 

 sively cold, the air temperature being often below zero fahrenheit, 



