Behavioural adaptations to Arctic winter: shelter seeking by Arctic hare (Lepus arcticus)

Abstract

Hares adopted a near-spherical shape while resting with only the thick pads of the hind feet touching the snow. Hares typically rested togther in closely spaced winter groups of up to 28 hares. Huddling did not occur, except in young littermates in summer. Hares in groups did not usually seek shelter, but solitary hares normally groomed, rested, and reingested win the shelter of large rocks. When wind speeds dropped below 10 km.-1, resting hares shifted from facing away from wind to an orientation towards the sun. As daily mean temperatures increased in April-May, the usual resting posture changed from the tightly curled resting sphere to crouching and sprawling. Hares used natural shelter, especially rocks and snowdrifts, and man-made structures. They also modified snowdrifts by drifting snow dens up to 188cm in length. Thirty-seven dens were seen in eight of 15 years of observations at Bathurst Island, and seven were seen on Ellesmere Island in one of five seasons. Snow dens were not used for feeding and their value as safety from predators is likely secondary to their value as shelter. -from Author