[sleightofmind]

Those dog teams they use in the Iditarod Race seem to be able to cover distances that would do man or horse proud. I don't know how dogs would do pulling a sled in a more temperate climate (assuming efficient, wheeled sleds) as their inability to sweat might drastically reduce their output. Years ago I saw a man using dogs to pull a sled at about 6500-ft of elevation in the summer in Southern California (near Big Bear). I suspect it was only for short trips, perhaps just a quirky hobby.

EDIT: Oops! Should have read farther in the comments. FartyMcFarter already mentioned Huskies just a couple of comments down.