Studying How Sled Dogs Run 1,100 Miles Through The Harshest Conditions May Help Human Endurance  Dogs are often called 'man's best friend,' and rightly so. Consider, for example, that they never interrupt us when we talk, are always happy to see us when we arrive home, and provide comfort when we are lovesick. Since dogs became domesticated 15,000 years ago, they have worked with and lived next to humans, which some say may account for the special bond. Each of the 400 breeds and varieties are unique, but only one stands out as the ultra-athlete canine: the racing sled dogs. |