It has long been known that a regular order of sex precedence exists among migratory birds. That a corresponding precedence should exist among aestivating and hibernating mammals is not surprising. The aim in this paper is to attempt to establish the facts in the matter of a supposed difference in time in which male and female squirrels go into aestivation and return from hibernation, as well as to determine the length of these periods for each, and to consider causes in seasonal variation in the matter of going into aestivation and coming from hibernation. The weather observations are based on local meteorological tables. From July I5 to 30, i9io careful field observations showed a rapid decrease of squirrels from no other apparent cause than aestivation. Though the morning of the 23d was fine and cool, these non-drinking squirrels were giving way to the instinct of aestivation before ripening vegetation, even in green alfalfa. Most of those seen were lower down, in stream beds, where the vegetation was greener, though fresh signs were still visible along the edges of barley fields and low pastures. Rain of the 2Ist had so laid the dust in the mouth of the burrows that it was possible to tell to some extent about the movements of the animals. While some of the burrows still showed fresh signs, many of them had not been used in three days. Even some of the dens in the most parched places showed signs of occupation. On the 29th, a field survey was made between the favorable hours of 6: 30 and 9: 30 A.M., in which no squirrels appeared at all while the observations lasted. Only two were seen during the forenoon. Climatic conditions during these observations are shown by the following record.
No takes yet. Share an insight, caveat, or question.
William T. Shaw (1925) studied this question.