Last week, a fishing guide in Alaska filmed a brown bear preying on an adult moose. The viral clip, which guide Sam Vassar described as “a once-in-a-lifetime occurrence”, shows the bear chasing the moose through a swift-running river before finally pushing the struggling animal underwater by its neck then dragging it back up onto the shore to feed.

Vassar’s Instagram post appears to be a compilation of multiple clips shot over the course of the protracted struggle. It begins with the moose successfully fording the river with the brown bear hot on its heels. Then the bear follows the moose into a willow thicket on the bank, the moose doubles back into the water, and the bear quickly overtakes it.

“I wanna stay far enough away so I don’t scare the bear off,” Vassar can be heard telling a passenger as he motors through the current. “Look, he’s got her!”

After swiping at the moose’s flanks multiple times, the brown bear starts tearing into its lower spine. Somehow, the moose pulls free from the assault, and predator and prey come head-to-head in the middle of the river. The moose stomps with its powerful front legs, but once the bear gains a grip on the ungulate’s neck—latching on where the neck meets the cranium—the battle is all but over.

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Both brown bears and moose are common throughout the state of Alaska. According to the Alaska Department of Fish and Game, brown bears live almost everywhere in the Last Frontier, except on islands south of Frederick Sound, west of Unimak in the Aleutian Chain, and the islands of the Bering Sea. As evidenced by Vassar’s video, they’re well-adapted to taking down both moose and caribou. They also feed heavily on winter-killed carrion, salmon, berries, roots, and various grasses.