On the warmer plains and valleys that surround the plateau, grazers are on the move. They left the high country to avoid the worst of the winter and now begin the long journey towards the heart of Yellowstone in time for summer. These elk are led by experienced adults who have made this trip many times before.

 

They are followed on their migration by the most ancient American grazers, pronghorn. Though predators may follow, none can outpace them. Over distance, these are the fastest animals in the world, taking the long migration in their stride.

 

Migrating elk and pronghorn must follow the advancing thaw, but higher up in the valleys, one animal is well ahead of them. Bison are adapted for cold. These herds need to be in Yellowstone early to have time to bring up their young in the short summer ahead.