Bears are among nature’s fiercest predators, possessing enough size, strength, and power to tackle most prey. But what if a bear added weapons to its arsenal?

The answer is that walruses could find themselves in real trouble. According to a new report published in the science journal Arctic, polar bears may be using tools to assault walruses. Such behavior was previously thought to be limited to cartoons.

The idea stems from Inuit accounts over the centuries of polar bears making use of rocks and other blunt-force objects to target walruses that may be idling below cliffs. Once thought to be apocryphal, scientists at the University of Alberta, Edmonton have done a thorough review of the accounts and found them to be credible. While rare, it appears polar bears do indeed seek to bludgeon walruses with the closest heavy weapon they can find—either rocks or chunks of ice.

Walruses pose a unique challenge for polar bears, who find their massive bodies (around 2500 pounds) and dense skulls difficult to deal with. By using a murder weapon, they might be more apt to take down a walrus.

The journal article references GoGo, a polar bear held in captivity at a Japanese zoo that has been observed throwing sticks and a tire at food just out of reach to try and knock it off its perch. Polar bears in Alaska have also been observed throwing ice at seals. It appears to not be a stretch to consider that polar bears may try to smash in walrus heads with the closest available tool.

[h/t Smithsonian]