Anyone who has put sled dogs in harness know that they are extremely eager and don't need coaxing. They also go far further than 100km speeds well beyond what p

Anyone who has put sled dogs in harness know that they are extremely eager and don't need coaxing. They also go far further than 100km speeds well beyond what people can do. The dogs lose their underfur in summer and can cover long distances then too (you can see this if you do a river trip with the dogs running on the riverbank). You'll also see wolves sometimes cover huge distances very quickly, regardless of season. Lack of a summer race does not indicate that those animals are not capable of it. Fair point about the road/track being more efficient than overland. People move much more slowly on the Iditarod trail whether on bike, skis, or running (http://www.alaskaultrasport.com/ http://www.alaskaultrasport.com/).