“Tuyuq,” a powerful Alaskan brown bear, has ruled his turf for 10 seasons. But a young challenger steps up and Tuyuq must fight to remain king bear.

An aging lioness and her pride struggle to survive in an isolated volcanic crater in East Africa.

A great white shark stealthily stalks her prey—jackass penguins, fur seals and cape gannet—in South Africa’s False Bay.