In the 2012 race, one of Lance Mackey's male dogs ripped out all of his 16 toenails trying to get to a female who was in heat. This type of broken toenail is extremely painful. Mackey, a four-time Iditarod winner, said he was too stubborn to leave this dog at a checkpoint and veterinarians allowed Mackey to continue to race him. Imagine the agony the dog was forced to endure. Learn more: http://helpsleddogs.org