Dogsled racing is a winter sport involving the timed competition of teams of sleddogs which pull a sled, on the runners of which the dog driver or musher stands. The team completing the marked course in the shortest time is adjudged the winner.
Generally the teams start one after another in equal time intervals, competing against the clock rather than directly against one another. This is due to logistic considerations of getting teams of from 3 to 24 excited sleddogs to the starting line for a clean timed start. Very few races use a mass start, which generally amounts to mass confusion.
Dogsled races may be sprint races over relatively short distances of 4 to 25 miles, mid-distance races from 20 to 200 miles, or long-distance races of 200 to over 1000 miles. Sprint races are frequently two or three-day events with heats run on successive days with the same dogs over the same course. Mid-distance races are either heat races of 20 to 80 miles per day, or continuous races of 100 to 200 miles usually. (These categories are informal and may overlap to a certain extent.)
Other modes of dogsled racing include freight races, in which a specified weight per dog is carried in the sled, and stage races, in which participants run a different course each day, usually from a central staging location.
Races are categorised not only by distance, but by the maximum number of dogs allowed in each team. The most usual categories are three-dog, six-dog, and 12 dogs or more (called open or unlimited); some races have four-dog and eight-dog classes instead of three and six.
Racing sleddogs wear individual harnesses to which individual tuglines are snapped, pulling from a loop near the root of the tail. The dogs are hooked in pairs, their tuglines being attached in turn to a central gangline. The lines usually include short necklines snapped to each dog’s collar, just to keep the dogs in proper position. It is unusual ever to see more than 22 dogs hooked at once in a racing team, and that number is usually seen only on the first day of the most highly competitive sprint events. Dogs may be omitted from the teams on subsequent days, but none may be added. Many other rules apply, most of which have been in effect since the beginning of organised dogsled racing in the city of Nome, Alaska, in 1908.
