Yellowstone Nature's Microworlds : Season 2 Episode 4

Steve's team investigates the Western wildlife in the Grandy Canyon, which was remarkably better helped by the reintroduction of the wolf then zoologists dared hope. Interaction with other predators proved minor. Although other prey species, like buffalo herds, are affected, the key are deer, whose unchecked grazing can undo the wood-/grass-land balance unless hunting wolves keep them in check.