Changes in daily activity rhythms of some free-ranging animals in Minnesota

Abstract

In the Cedar Creek Natural History Area, gray squirrel Sciurus carolinensis, red fox Vulpes vulpes, muskrat Ondatra zibethicus, ruffed grouse Bonasa umbellus and barred owl Strix varia show marked seasonal changes in activity patterns, which are believed to be responses to environmental conditions or physiological and behavioural requirements of the animal. Variations in number of activity periods, total minutes of activity, timing of activity in relation to sunrise and sunset, and in the amount of rest during the normal active period are related to changes in such factors as temperature, snow cover, food supply and breeding behaviour. Controlling mechanisms are sufficiently plastic to allow animals to alter their behaviour significantly in response to a changing environment. Animals in captivity show remarkably precise timing with respect to activity rhythms. -from Author