WATCH: Two Huge Grizzly Bears Attack and Kill Another in Yellowstone National Park

by Lauren Boisvert
(Image Credit: Paul Souders/Getty Images)

Back in May, photos surfaced of a blood-curdling attack involving a big grizzly bear killing a younger, smaller bear in Yellowstone National Park. First, only the photos made the rounds. But now the Instagram page Nature is Metal has released video footage of the fight, which is honestly hard to watch due to its ruthless nature.

There is a third bear involved, seen hanging around in the woods, almost pacing back and forth. This is the mother of the smaller bear. The big grizzly was trying to mate with her, and the presence of another male–even the female’s biological offspring–isn’t tolerated in the bear world. So, a fight ensued.

Photographer and frequent Yellowstone visitor Paul Allen was photographing the smaller bear on May 22 when the larger male showed up. Allen captured photos of the subsequent fight and also shared his theories on why the fight ensued. According to Allen, the smaller bear was only 50 yards away from a group of tourists looking on.

Photographer Captures Harrowing Images of Grizzly Attack, Explains Theories Why It Happened

“I’m no grizzly expert,” said Allen, “but I’ve been coming to Yellowstone to shoot photos for about 20 years. I’ve seen lots of bears over the years, and I have a theory of what occurred. If the young bear knew [the other two bears] were near I believe he would have run away.”

According to Allen’s photos and commentary, the mother bear actually charged her offspring, possibly trying to chase him off.  “I think she was trying to run the young bear away,” said Allen. “She knew it was her cub. She was being courted and mated by the larger male grizzly, and a female won’t actively mate until their young leave them. The female was fighting the young male when the bigger male bear showed. He is the biggest grizzly I’ve ever seen in Yellowstone, about 500 pounds, aggressive and full of fight.”

Though, as the fight ensues, it’s clear that the mother bear was just as much a violent participant as the bigger male was. One of Allen’s photos shows her actively engaged in attacking her offspring. Female bears know that their cubs must be gone when they mate again. By aiding in the attack, she made sure that her cub would permanently not be around.

Allen mentions that many viewers want to romanticize the aspect of the mother’s first charge at the young bear as if she was truly trying to warn him and chase him off. But that’s not really the reality. Bears can be ruthless, even to their own offspring.

Yellowstone Grizzlies Initiate Brutal Fight, Eventually Killing Smaller Bear

In the end, the huge male grizzly eventually mauled the young male so badly that park rangers arrived on the scene. Yellowstone National Park staff arrived and chased off the bears, monitoring the young bear before determining that he wouldn’t survive. They humanely euthanized him and removed the carcass.

Among the significant injuries, the bear sustained “massive head, neck, and spinal wounds, a broken right shoulder and a laceration in the right flank exposing its organs,” according to a report from Outdoor Life.