The finale shows why a summer with soaring temperatures poses a threat to Yellowstone's ecosystem. Also: the Great Gray owl family faces a major fire in the Beartooth Mountains; and a wolf pack has 11 pups to feed.
Part 2 of 3. How spring brings new life and a break from the brutal winter temperatures. The dangers aren't over, however, as wildlife families face a torrent of water cascading down the mountains as the great thaw gets underway. Beavers are in particular danger.
The three-part documentary series about wildlife at Yellowstone as winter morphs into spring and summer begins. First up: the brutal winter, including whether grizzlies that emerge early from hibernation can survive; why wolves and Great Gray owls are in danger of starvation; and how Yellowstone's unique geology affects bison.