Joe Riis: Tracking the Migrations of Yellowstone

Wildlife biologist turned photojournalist Joe Riis documented the migrations of pronghorn, mule deer and elk in the Greater Yellowstone Ecosystem for nearly a decade — following the animals over rocky passes, through swollen rivers and across remote wind-swept ridges. His groundbreaking work offers a fresh perspective of the park, and, he hopes, encourages a new appreciation and understanding of its crucial role for wildlife.