From WIKIPEDIA: Sledge dogs are a group of dog breeds and mongrels that, historically, were bred for the purpose of pulling a dog sledge. They were important for transportation in arctic areas, hauling supplies in areas that were inaccessible by other methods. They were used with varying success in the explorations of both poles, as well as during the Alaskan gold rush.
They are used for recreational purposes, and are raced in events known as dog sledge races such as the the Yukon Quest. Numerous sledge dog breeds are also kept as pets or raised as show dogs.
From CLODO: I have found a new breed of sledge dog!
In the WS, another picture, less attractive in my mind