Yoakum, Behavior of Squirrels. 543 



accounts cited above, give us the longest connected accounts of the 

 habits and life of the squirrel. Their citations practically cover the 

 published observations on the squirrel. 



The literature as a whole gives a fairly accurate account of the 

 squirrel as he is seen by the casual observer. Systematic observa- 

 tion and investigation of his associative processes are lacking. 



Mills found that the chickeree, Sciurus hudsonius, was highly sus- 

 picious of any trap or box set to catch him. If caught in one once 

 or twice, he would no longer even investigate the trap. On the other 

 hand, the chipmunk, Tamias lysteri, would enter the trap as often as 

 he came near it. Mills considers this an evidence of the superior in- 

 telligence of the red squirrel. He makes no attempt to explain the 

 difference in behavior upon the basis of the striking difference in 

 the nesting habits of the animals, the former nesting in trees, the lat- 

 ter burrowing underground. Mills cites the observations of other 

 writers on this point.'^ Numerous scattered obsen^ations are col- 

 lected by this author and by E. Ingersoll, quoted above. We have 

 not repeated these citations, since they are available in their present 

 form and have little bearing upon the further investigations of this 

 paper. 



II. Some Experiments upon the Associative Processes of the 



Grey Squirrel. ; 



1. The Method of Taming the Squirrel. — The task of taming the 

 grey squirrel is often a difficult one. Some of the animals under 

 observation for as long as six months failed to become entirely tame. 

 Others, captured in semi-wild state, in parks, etc., became sufficiently 

 tame to be used for experimentation in less than two months. The 

 squirrel is compelled by his environment to be ever on the alert, and 

 his arboreal habits make confinement jDarticularly distasteful. 

 Caging without the wheel or in small cages tends to make them weak 

 and unhealthy. If the squirrel be supplied with hard nuts and 

 wood upon which by gnawing he may exercise his muscles and* keep 

 his teeth at their normal length, he may be kept for long periods of 

 time in a fairly normal condition. 



"Op. cit., pp. 52 fe. 



