Watch: Yellowstone grizzly bear runs for its life, but from what?

A photographer has shared footage of a grizzly bear sprinting for cover while being chased by another critter in Yellowstone National Park.

Bo Welden, a naturalist and guide for Jackson Hole EcoTour Adventures, asked Instagram followers last week to identify the other critter before it appears in his footage (posted below).

The answer, as many might have guessed, is a bison. More precisely, a momma bison protecting a calf near the Lamar River.

“A mother bison showed this grizzly bear that he is not the biggest baddest beast on the landscape,” Welden wrote. “It was truly AMAZING to be able to witness this role reversal while on tour with Jackson Hole EcoTours guests! We were stunned to see this moment in real time.”

What stands out is the speed of both animals.

Grizzly bears can attain a top speed of nearly 40 mph, while a sprinting bison maxes out at 35 mph.

It’s rare, however, to witness both animals running at full or nearly full speed.

Welden told FTW Outdoors that the bison herd, with other mommas and calves, was just “around the corner from the bear.”

He added that while the bear was chased away, it stayed in the vicinity and was later spotted feasting on the carcass of a 2- to 3-year-old bison that it had discovered nearby.

“A wise choice,” Welden said, “compared to attempting to kill a red dog that still had a protective mother around.”

Welden captured his footage in early summer when first-year bison calves still boasted their “red dog” coloration and were extremely vulnerable to predation from bears and wolves.

–Generic grizzly bear image atop this post is courtesy of Yellowstone National Park

Story originally appeared on For The Win