Bears Attacking — and Eating — Other Bears Is Considered Normal

On the last day of September 2024, the Fat Bear Week contest was set to begin. But two brown bears were caught in a deadly struggle that was live streamed across the world.

The two bruins bobbed up and down on the Brooks River on the Alaskan peninsula, splashing, tussling, and snapping their jaws at one another. The male bear, 469, drowned the female bear, 402, and took bites from her body.

Researchers say that, while killing and cannibalism are normal parts of bear behavior, it’s impossible to know why bear 469 attacked bear 402 when he did. Michael Fitz, naturalist and Fat Bear Week founder, says he often finds himself wishing he could ask bears why they’re doing what they’re doing.

From an evolutionary point of view, members of one’s own species — known to biologists as conspecifics — are a precious potential food source for animals in their contest to survive and reproduce.

Yet, the risk of cannibalizing a diseased conspecific seems to offset this benefit. Cannibalism has also transmitted neurodegenerative diseases, such as mad cow disease, and, in humans, a disease called kuru.

Read More: Why Cannibalism Is A Common Behavior For Some Animals

In this case, Larry Van Daele, who has spent over four decades working with coastal brown bears, notes that bear 469’s patches of lighter-colored fur, from which he gets his nickname Patches, may be “old scars from serious wounds received during battles with other bears.” In 2012, bear 469 Patches was found guarding the body of another dead bear that rangers described as a food cache.

Each bear also has a distinct personality and history, suggesting that bear 402 and 469, who were both older bears, may have already been familiar with one another, and that this unknown history may have been a factor in 469’s aggression.

After bear 469 dragged the body of 402 to shore, Fat Bear Week's most dominant Brooks-River bear, 32, took over the body and proceeded to feed on it.

“When a bear finds another dead bear, they don’t seem to be shy about eating a dead bear,” Fitz told me.

Although bear 469 appeared fat and healthy to bear experts, the animal’s seasonal hyperphagic appetite — an extreme form of hunger — may still have been a factor in the killing. Katmai ranger Sarah Bruce points out that the bear enthusiast Timothy Treadwell and his girlfriend Amie Huguenard were also killed by a bear with hyperphagia in 2003.

The Fat Bear Week organizers found bear 402’s death upsetting, even though they recognized the killing as normal wild bear behavior. Naomi Boak, Katmai Conservancy communications and media consultant, suggests that it’s beneficial for people to see brown bears as the wild creatures that they are.

“I think it is healing to have a deep connection to nature because we as human beings often don’t face the realities of our own lives and death,” Boak says. “And I think that learning from other creatures, other living beings, and not anthropomorphizing, but learning about their worlds, and the lives they face, helps us understand our own lives better.”

Read More: Cannibals in Nature Are More Common than Once Thought

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• Explore Blog. The Violent Side of Nature