A video of a wolf biting a grizzly bear on the butt at Yellowstone National Park has gone viral.
The footage, taken by Gary Gaston on Saturday, shows the wolf sneaking up behind the bear before chomping down!
"Look he got him right in the butt!" someone says before the wolf goes in for a second bite.
"The bear sat down after it was bitten, then as soon as the wolf walked away it did too," Gaston told FTW Outdoors.
Gaston says the video was taken at Crystal Creek near Slough Creek at daybreak.