Sport of racing sleds pulled by dogs over snow-covered cross-country courses. It developed from a traditional Eskimo method of transportation. Modern sleds are usually of wood (ash) construction, with leather lashings and steel-or aluminum-covered runners. Sled dogs are usually Eskimo dogs, Siberian huskies, Samoyeds, or Alaskan malamutes; teams typically consist of 4-10 dogs. The course is usually 12-30 mi (19-48 km) long, though some, including the Iditarod, are considerably longer