Sled dogs are the best long-distance runners in the world.
Huskies can travel over 100 miles in a day, running steadily at 8-10 miles per hour. Sled dogs were bred by native peoples for pulling people or loads over snow and ice. Today, their breeding and purpose is much the same. Huskies wear little booties to protect their feet in bad snow conditions. This beats the alternative of the musher having to suck the dogs' feet in below-freezing temperatures to melt the sharp icicles between their toes so they don't get hurt.