Global warming could turn polar bears into maneaters, study finds

Global warming and polar bears. It doesn’t sound like a good combination, and it isn’t. At least for us.

A new study on polar bears has concluded that far from being the man-eating killing machines of common lore, polar bears are not prone to attack humans. But that could change, as loss of sea ice due to global warming is hurting the bears’ ability to hunt for food — and, as the historical evidence shows, it’s been mainly hungry polar bears that are willing to take the risk of attacking humans.

Conducted by an international team of researchers from the United States, Canada, Norway, Russia and Greenland, the study collected data on polar bear attacks in all of the bear’s habitat regions between the years 1870 and 2014. They found 73 documented cases of wild polar bear attacks, 20 of which resulted in human fatalities and 63 in human injuries.

All things considered, that number is a relatively small one for a span of almost 150 years (grizzly bears in Alberta, alone, caused 42 serious or fatal human injuries between 1960 and 1998). And it says something about the bears’ general reluctance to hunt humans for food, say the study’s authors, whose work does not include data from Arctic Indigenous populations.

“They’re portrayed as these extremely dangerous man-eating beasts that are looking to attack people, which I think is fairly inaccurate,” says Jim Wilder, researcher with the US Fish and Wildlife Service in Alaska and study co-author, to the Canadian Press.

Wilder says that because polar bears are pure game hunters, unlike grizzly and black bears who eat plants as well, they are less likely to want to tangle with humans and risk injury. “If they get injured, that impairs their ability to hunt,” Wilder said. “There isn’t a lot of incentive for them to be aggressive — unless times are bad.”

Of the recorded attacks, the researchers characterized 59 per cent as instances when polar bears were actually hunting humans for food, with nearly all of such instances involving predatory attacks on small groups of one or two people. By contrast, a smaller percentage of attacks were said to be made for purposes such as defence of cubs, defending a fresh carcass or when the bears were being provoked by humans.

Thus, the researchers concluded that the most likely threat to human safety comes from nutritionally stressed adult male polar bears, a fact that is likely to become more of a reality as climate change warms up the Arctic.

“Polar bears now face a new and unprecedented threat due to the effects of climate change on their sea ice habitat,” say the study’s authors. “Although the current status of polar bear subpopulations is variable, all polar bears depend on sea ice for fundamental aspects of their life history.”

Going forward, the researchers argue that authorities in the five polar bear Range States (the US, Canada, Greenland, Norway and Russia) need to take proactive steps to minimize the change for human-polar bear conflicts and to work on developing more effective polar bear warning and deterrent systems.

The new study was recently published in the Wildlife Society Bulletin.