Grizzly Bears Are Dying in Record Numbers — And the Killer Isn't Human

Grizzly bears in Yellowstone are dying in record numbers — 74 in a single year, the most ever recorded. After 50 years of conservation success, biologists finally know what's killing most of them. It's not hunters. It's not wolves. It's something far stranger. 0:00 - No Natural Enemy, Record Deaths 1:46 - The Brink of Extinction 3:49 - The Human Factor (85% of Deaths) 6:36 - The Cub Survival Paradox 8:13 - Killers Among Their Own 14:03 - Wolves: A Minor Player 15:41 - Three Theories Nobody Can Prove 21:04 - What Scientists Still Don't Know