Summer Snow Dens Used by Polar Bears in the Canadian High Arctic

This paper describes the use of snow dens by polar bears during two summers on northern Baffin and Bylot Islands. More dens were found during 1976 than 1975, probably because of heavier snow during 1976. Dens were of three types, shallow surface pits, shallow dens, and deep burrows

Movement of Four Satellite-Monitored Polar Bears in Lancaster Sound, Northwest Territories

Four female polar bears, fitted with satellite-monitored transmitters at Lancaster Sound, N.W.T. during May 1979, were tracked to determine seasonal distribution, movements relative to ice conditions, and home range. Most locations (68.7%, n = 46) of satellite-tracked bears were on landfast ice, 13.4% (n = 9) on old pack ice, 13.4% (n = 9) on land, 3.0% (n = 2) on bergy water, and 1.5% (n = 1) on young pack ice. These observations support the conclusions of mark-recapture studies in the area, that landfast ice is favored until breakup when bears move onto land. Data from the satellite-tracked bears indicate that they had home ranges.Key words: polar bear, telemetry, satelliteMots clés: ours blanc, télémesure, satellit

Polar Bear Denning Area at Gateshead Island, Northwest Territories

A survey during 1977 found that the Gateshead Island area, Northwest Territories, had 9 confirmed and 10 suspected polar bear dens. The importance of the area for polar bear reproduction was confirmed during a survey in 1982 when 15 dens were found, 10 of which were identified as maternity dens. The area should be protected from human intrusion.Key words: polar bears (Ursus maritimus), denning, reproduction, Gateshead Island, Northwest TerritoriesMots clés: ours blancs (Ursus maritimus), tanières, reproduction, l'île Gateshead, Territoires du Nord-Oues

Distribution, Movement and Abundance of Polar Bears in Lancaster Sound, Northwest Territories

Mark-recapture studies show that polar bears are distributed at varying densities throughout Lancaster Sound during winter and spring. Major concentrations occur along the north and south coasts and the transverse floe edge at the mouth of the sound. As the ice melts, some bears move west whereas others move to nearby land areas. There is some evidence that as the ice forms, polar bears return from their summer locations to eastern Lancaster Sound. Polar bears of Lancaster Sound are part of the larger population whose western range extends to Barrow Strait, Prince Regent Inlet, Wellington Channel and Jones Sound. The southern and eastern range limits are unknown although this population may extend at least to Clyde River on northeastern Baffin Island and probably to Greenland. Maternity denning appears to be widespread over the study area probably because of the abundance of suitable habitat. We estimated a population of 1031 ± 236 polar bears in Lancaster Sound during 1979: however, more estimates are needed to determine if this relatively high number is normal for the area.Key words: polar bear, distribution, movement, abundance, Baffin Bay, Lancaster Sound, summer retreat, dennin

Observations of Intraspecific Aggression and Cannibalism in Polar Bears (Ursus maritimus)

Cannibalism in polar bears appears to occur as carrion feeding and as attacks by males on small cubs or incapacitated individuals. Direct observations indicate that intraspecific killing and cannibalism occur among polar bears throughout the Arctic. The high incidence of Trichinella infection and circumpolar observations of cannibalism suggest that polar bears will readily eat other polar bears when they can do so without excessive risk of injury. Speculations that intraspecific aggression and cannibalism may be an important social and ecological force are consistent with existing information on polar bear biology.Key words: aggression, cannibalism, parasitism, polar bears, population dynamics, Trichinella, Ursidae, Ursus maritimusMots clés: agression, cannibalisme, parasitisme, ours blancs, dynamiques des populations, Trichinella, Ursidae, Ursus maritimu