This Month in Photo of the Day: Animal Migration Photos

In the untamed early days of the American West, pronghorn like those pictured here in Wyoming’s Grand Teton National Park were plentiful and proud and moved freely. Driven by the seasons, their migration from the mountains to the valleys and back has always been a tough journey, but now fences, borders, bloated rivers, and other constraints have created blockades and bottlenecks that result in devastating losses for this critically endangered species.

The National Geographic Young Explorer program funded photographer Joe Riis with a grant to document the 2008-2009 pronghorn migration.

Watch Great Migrations this month on the National Geographic Channel »
Find out more about U. S. National Parks »