The food of this ground-squirrel consists of a few grasshoppers, crickets and beetles, some grass blades and other tender leaves and growing tips, a few roots and a very large proportion of grains and other hard seeds. Soft fruits, apples and berries are not despised, but seeds must be regarded as the staple diet of the animal.
The home is an underground chamber, reached by a hole going down almost vertically for about a foot and then turning horizontally and ramifying into two or more passages. Generally there are two or more vertical passages connecting the burrows with the outer world. The young are born in these subterranean homes some time during the early summer. The family breaks up in the late summer and apparently the young make new burrows for themselves and the animals hibernate singly, but 'of this I am not sure.
Hibernation begins at the onset of cold weather. The exact date of their final retirement to winter quarters varies with the season, the locality and the individual, and yet there is a certain amount of uniformity about it. Thus in 1909 in southern South Dakota there was no frost until October 9 or 10, when the temperature suddenly dropped and on October 11 it was several degrees below freezing point with a bitter northerly wind that made it seem much colder. Until this "cold snap" I had seen ground-squirrels daily. Afterward, there was a period of three or four weeks of very balmy weather, but I did not see another ground-squirrel although I had excellent opportunities had they been active.
The end of their hibernating period varies somewhat and it probably depends somewhat upon the temperature. On the banks of the Missouri River, in South Dakota, the first of these little animals are usually seen whisking about their burrows some time late in March. Usually a number are to be seen on the same day that the first one appears. In this they show a striking similarity to the woodchuck as they also do in their habit of staying out in all kinds of weather, once they have made the venture. Thus in the spring of 1910 in mid-April we had a snowstorm lasting two days and piling the snow up three feet deep in places. The very day that the storm subsided I saw ground-squirrels running cheerfully about, buried to their hips in snow.
A captive animal of this species afforded opportunity for a very interesting winter study. He was captured in an insect net in September and placed in a wooden box which had a front of fine wire mesh. He was fed corn, small grains, potato, apple and sweet potato. Water was given him also but he did not seem to use any of it and I finally ceased to give it. The small grains were the favorite food and he would not eat the outer part of the corn grain unless driven by actual hunger although the heart (embryo) of the grain was gnawed out. The cage was kept in the supply closet of my laboratory. The former was without
