Study: In Conflicts Between Grizzlies and Polar Bears, Grizzlies Win

   12.21.15

Ever wonder who would win in a fight between a grizzly and a polar bear? Both rank among the most powerful predators in North America, but common sense suggests that since polar bears are larger, it would give them a significant edge in any conflicts with their brown cousins. However, a new study by the US Fish and Wildlife Service found that in encounters between the two species, polar bears often end up losers.

For the study, researchers documented the best place to observe grizzly and polar bear interactions: a boneyard of harvested bowhead whales near Kaktovik, Alaska. The bone pile is vital to the survival of polar bears during the summer-autmn open water period, when ice extent was reduced and the animals were forced to hunt more on land. However, they are not the only ones to stake a claim on the whale meat. Grizzlies have come as well, and they’re not keen on sharing.

It should be noted that conflicts between polar bears and grizzlies rarely break out into brawls. Although there were more polar bears at the bone pile and they were significantly larger than the grizzlies, researchers said that most interactions between the two species ended in the polar bears leaving. While the polar bears would occasionally fight among themselves, the presence of even a single grizzly was enough to cause the Arctic bears to turn tail.

Oftentimes grizzlies were only roughly half the size of the polar bears present. Had the encounters turned into fights, the polar bears would have brawn and numbers on their side.

“You can be watching the polar bears at the bone pile and all of a sudden they’ll split. And you kind of know from past experience that there’s probably a grizzly bear walking up the beach,” Richard Shideler, a biologist for the Alaska Department of Fish and Game who was part of the study, told Alaska Dispatch News. “I think it’s attitude. They’re more aggressive in terms of bear-bear interaction.”

Researchers said that compared to grizzlies, polar bears are submissive. This is because grizzlies openly show their aggression in the way they walk and behave, which may have provoked the milder polar bears to flee instead of fighting. Scientists also attributed this dynamic to the fact that polar bears generally hunted in the ocean, whereas grizzlies were more accustomed to competing and fighting over food on land. In addition, the grizzlies need to get all the food they can before they enter hibernation, so they may be somewhat stressed. Polar bears, on the other hand, do not hibernate.

Despite the reluctance of either species to interact with each other, grizzly-polar bear hybrids have been found in the wild. They are more common in areas where the two animals often meet, such as on Banks Island in Canada.

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