November 30, 2009
Shrinking sea ice may be to blame for recent polar bear cannibalism incidents in Canada. Eight cases of adult polar bears eating bear cubs and other bears near Churchill, Manitoba, have been reported. Four of the cases were reported to Environment Canada and four to Manitoba Conservation.
While adult male polar bears, Ursus maritimus, have been known to kill and cannibalize cubs, most cases occur in the spring when the male can impregnate the female. Due to the timing of the incidents, some believe hunger may be the reason for this year’s incidents.
By early November, the ice in Canada’s Hudson Bay is normally solid enough for polar bears. But with December rapidly approaching, the ice is just not solid enough. Polar bears depend on annual sea ice as a platform for hunting, a place to raise young and as a habitat for mating. As the ice shrinks, starving polar bears are not only resorting to cannibalism, but are also drowning. Four polar bears drowned in 2004, trying to swim between ice and shore.
According to the US Geological Survey (USGS) and the Canadian Wildlife Service (CWS), the impact of climate change on the species in western Hudson Bay, has resulted in a 22 percent reduction in the population. 1,194 polar bears lived in western Hudson Bay in 1987. By 2004, only 935 remained.
Listed as Threatened on the IUCN Red List, oil spills, pollution and hunting threaten the species. But according to some, climate change is the most serious threat to the polar bear population.