Stunning Footage: Epic Animal Migrations in Yellowstone

Some of the world’s most incredible animal migrations take place in the Greater Yellowstone Ecosystem. Among them are a 120-mile pronghorn migration and nine elk herds with unique migration patterns. While on assignment in Yellowstone, Joe Riis was able to capture the awe-inspiring migrations that few tourists get to see. Click here to read more about pronghorn: Click here to read more about elk: