Study Suggests Polar Bears Use Tools to Kill Walruses

A new study has produced evidence to suggest that centuries-old Inuit tales of polar bears killing walruses by smashing their skulls with heavy objects are factual rather than fictional.

By reviewing firsthand and secondhand accounts authored by both Western naturalists and Inuit hunters, the study authors, Ian Stirling, Kristin Laidre, and Erik Born, evaluated the veracity of anecdotal reports that polar bears bludgeon walruses to death with rocks or blocks of ice.

Their findings, which were published in the June issue of the scholarly journal Arctic, indicate that comparable behavior does occur in the wild, albeit infrequently. Polar bears, they wrote, may rely on this tactic to hunt walruses "because of their large size, difficulty to kill, and their possession of potentially lethal weapons for both their own defense and the direct attack of a predator."

In addition to humans, crows, orangutans, and many other animals have been known to manipulate their surroundings for their own ends. Archer fish spit water at vegetation to dislodge insects; elephants, chimpanzees, and capuchin monkeys use leaves and branches to purge their fur and skin of parasites; dolphins in Australia's Shark Bay wear sea sponges on their noses to prevent injury as they forage on the sea floor.

Since 1780, stories of polar bears acting in a similar manner have circulated in the Western scientific community. Inuit hunters told white explorers and naturalists about the practice, but their accounts were often dismissed by the scientific establishment as fabulous. As recently as 2009, the author Richard Ellis described such reports as "mythological," according to the study. But Stirling wasn't so sure.

"It's been my general observation that if an experienced Inuit hunter tells you that he's seen something, it's worth listening to and very likely to be correct," he told Science News.

He and his colleagues set out to review the available evidence to make a determination. In addition to the prevalence of contemporary accounts, they wrote, circumstantial evidence also supports the idea that bears are capable of conceptualizing the potential of tools in acquiring and accessing food. In 2010, a Japanese reporter photographed a 5-year-old male polar bear named GoGo successfully employing pipes, tree branches, logs, and toys to knock down a piece of meat that had been suspended three meters above his pool at Osaka's Tennoji Zoological Gardens; he subsequently sent the photographs to Born.

Considering, the authors wrote, it's not inconceivable that "an occasional adult polar bear might be capable of mentally conceptualizing a similar use of a piece of ice or a stone as a tool to attack the well-protected brain of a walrus in order to kill it." What's more, they added, female bears may impart this knowledge to their cubs, ensuring that it is passed down through the generations.

Newsweek reached out to Born for comment but did not immediately receive a response.

A polar bear walks on frozen tundra.
A polar bear walks on the frozen tundra in Canada. A new study claims that bears have used tools to kill walruses. PAUL J. RICHARDS/AFP/Getty Images