The brief April 25 encounter at Blacktail Ponds in Yellowstone National Park was filmed by wildlife photographer Mark Fletcher, who said the bear fled uphill after a second coyote joined the attack.
No animals made contact, and retired biologist Franz Camenzind said the behaviour fits coyote parents aggressively defending pups, which are typically born in April.
Experts said even packs usually avoid healthy adult grizzlies, making the pair's response unusual; Blacktail Ponds attracts bears and other scavengers because bison carcasses can collect there in spring.
Was Yellowstone's young grizzly truly defeated, or just wisely avoiding a parental squabble?
Are wolves making Yellowstone's coyotes bolder against other predators like bears?
As food sources dwindle, will clashes between grizzlies and other predators intensify?