Iditarod Trail Sled Dog Race early in the 20th century. The main route of the Iditarod trail extends from Seward in the south to Nome in the northwest, and was first surveyed by Walter Goodwin in 1908, and then cleared and marked by the Alaska Road Commission in 1911 and 1912. The entire network of branching paths covers a total of . Except for the start in Anchorage, the modern race follows parts of the historic trail. The trail is composed of two routes: a northern route, which is run on even-numbered years, and a southern route, which is run on odd-numbered years. Both follow
Iditarod Trail Sled Dog Race and forage for food when the ground is thick with snow. As a result, the moose sometimes prefer to use pre-existing trails, causing hazards for the dog teams. In 1985, Susan Butcher lost her chance at becoming the first woman to win the Iditarod when her team made a sharp turn and encountered a pregnant moose. The moose killed two dogs and seriously injured six more in the twenty minutes before Duane "Dewey" Halverson arrived and shot the moose. In 1982, Dick Mackey, Warner Vent, Jerry Austin, and their teams were driven into the forest by a charging moose. Otherwise,