A sobering video recently posted to Instagram shows a rarely-filmed instance of black bears working in tandem to bring down vulnerable prey. The viral clip, shared by @natureismetal on March 30, captured two black bears taking down a struggling moose calf after the animal was separated from its mother during a wolf attack. It was originally filmed in Ontario, Canada in September 2023.

“They were certainly big bears, however it was also a young calf, probably only about quarter/half the size of an adult moose,” wrote photographer Anna-Mari Muller in the comments below a still frame photo of the incident she shared back in October. According to Muller, the calf’s mother was tucked away in the weeds nearby when the predation event took place.

The calf is seen standing in a lake as the bears attack, but they eventually pulled it up onto the shore, Muller’s Instagram post states. Her photos also show one of the wolves that originally attacked the calf before the black bears showed up to finish it off.

Muller filmed the encounter from a lake access point inside Algonquin Provincial Park. Her video is hard to watch, but it documents an important aspect of black bear behavior. Over the years, scores of studies have shown black bears to be formidable predators of juvenile moose—particularly when there are no grizzlies around to compete for the prey. A 1980 study conducted by the Alaska Department of Fish & Game, for example, found that black bears were responsible or a whopping 59 percent of all moose calf mortality on the Kenai Peninsula.

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Ontario is mostly devoid of grizzly bears, but Algonquin Park—which sits in the southeastern part of the province about three hours north of Toronto—has approximately 2,000 black bears and somewhere between 3,000 and 5,000 moose. The 1.2 million-acre park is also home to between 30 and 35 separate wolf packs.