INTELLIGENCE OF SQUIRRELS. 833 



ing," or " in winter-sleep/' deviates functionally from the normal ; 

 also, that the exact time of the observations be recorded. There 

 is a certain amount of evidence that even birds, representing 

 the highest type of activity, may possibly hibernate ; and that 

 many animals, not usually thus affected, may become so under 

 exceptional circumstances indeed, that man himself, owing to 

 peculiar states of the nervous system, may pass into a condi- 

 tion ("trance") having much in common with the hibernation 

 of lower animals. I think it is very probable that, when the 

 matter has been fully investigated, all degrees of cessation of 

 functional activity will be found represented, from the normal 

 daily sleep of man and other animals, to the lowest degree of activ- 

 ity consistent with the actual maintenance of life. The flying 

 squirrel is nocturnal in habits and exceedingly active, even in 

 confinement, as Prof. Perkins (loc. cit.) has shown ; but during the 

 daytime it seems not to be correspondingly quick in a condition, 

 in fact, resembling somewhat that of a hibernating animal. The 

 " diurnal hibernation " of the bat is not to be forgotten. I noticed 

 that my chipmunk invariably, after feeding, tucked his head 

 down and assumed a more or less ball-like form highly suggestive 

 of a tendency to hibernation. 



There are many questions that arise in connection with this 

 subject, one of which bears directly on the subject of comparative 

 psychology: How and to what extent is the intelligence of animals 

 influenced by hibernation? It may be considered pretty clear that 

 both the ground squirrel and the flying squirrel hibernate, and 

 these are certainly among the lowest perhaps are actually the 

 lowest in intelligence of the whole tribe. "We know that struggle 

 among higher animals develops mental adaptation and other 

 forms of intelligence, and it is rational to suppose that those spe- 

 cies of squirrels that do not hibernate throughout the winter, but 

 endeavor to prevail over their surroundings, as well as to adapt 

 themselves to them, should be more intelligent than those spend- 

 ing a large portion of each year in inactivity. 



My chipmunk, during its captivity, under certain circum- 

 stances, kept to his original habits e. g., when a single nut was 

 given him he would eat it immediately, but if several were pre- 

 sented at once he would hide them one by one in a corner of his 

 cage, or, if sufficiently small, pack them away in his cheek-pouches. 

 He did the same with cereal grains. When cotton wool or web- 

 like material was placed in the cage, he manipulated it a good 

 deal, but finally made a bed of it, in which he buried himself out 

 of sight. 



Within the last ten years attention has been called to " sing- 

 ing " in certain rodents, especially mice ; but from numerous ref- 

 erences in the literature it appears that " singing," or something 



vol. xxxvi. 53 



