i OUR GRAY SQUIRRELS 25 
dive down, perhaps clear out of sight, and in a 
moment emerge with the nut in their jaws. 
Two hypotheses have been advanced in explana- 
tion of this unerring recovery of their treasures. 
One is that the animal remembers. But the diffi- 
culty of assuming this, under all the circumstances, 
is so great, that it seems easier to believe the alter- 
native explanation, namely, that the treasure is 
found by aid of the sense of smell. It certainly 
seems to ws that a hickory nut, after having been 
buried three or four months, and covered with a 
foot or two of snow, would be as unsmellable as 
anything could be; but it won’t do to limit the 
sensitiveness of a squirrel’s nose until we know 
more about it than we do at present. 
At any rate, nearly, if not quite all, the nuts 
buried are exhumed before spring, for few hickory 
or oak saplings spring up in our grove, as would 
happen if any considerable number of seeds were 
left in the ground. Thoreau has a great deal to 
say on this topic in his suggestive essay on the 
Natural History of Massachusetts (in “ Walden”), 
and credits the squirrels with doing an immense 
amount of tree-planting. 
In confinement these squirrels will often attempt 
to bury nuts in the floor of their cages, going 
through the digging, covering, and patting motions 
as if the article were really buried. A writer in 
The American Naturalist for 1883 described this 
behavior on the part of a flying-squirrel which had 
