A study conducted by American and Canadian scientists examined three instances of polar bears preying on each other from January to April 2004 in northern Alaska and western Canada. The study included the first-ever reported killing of a female bear shortly after the animal gave birth.
Polar bears primarily feed on ringed seals and use sea ice for feeding, mating and giving birth.
Steven Amstrup of the U.S. Geological Survey Alaska Science Center was the study's principal author. He noted observing polar bears killing for population regulation, dominance, and reproductive advantage, but killing for food was much less common.
Kassie Siegal of the Center for Biological Diversity of Joshua Tree, California, said the new information is very important and shows in a graphic way how severe the problem of global warming is for polar bears.
Environmentalists claim shrinking polar ice due to global warming may lead to the disappearance of polar bears before the end of the century.