View of the Griffith Observatory, Los Angeles, California

© Walter Bibikow/Getty Images

View of the Griffith Observatory, Los Angeles, California

North American river otters can run on land at speeds up to 15 miles per hour, and have been documented sliding across snow and ice when a quick escape is required. But they’re incredibly well suited to swimming, even when winter brings a deep freeze to Yellowstone National Park. Their thick pelt and long, tapered body help them glide through the water, propelled by their short legs and webbed feet. They’ll even swim below the surface of a frozen lake or river, staying submerged for nearly eight minutes before they have to find a hole in the ice and refill their lungs.