Sled dog each year, but after the 1995 events, it was decided to hold them every two years, which facilitated the bidding process and enabled the host organization more time for preparation. Togo was the lead sled dog of Leonhard Seppala and his dog sled team in the 1925 serum run to Nome across central and northern Alaska. Balto was the lead dog of the sled dog team that carried the diphtheria serum on the last leg of the relay to Nome during the 1925 diphtheria epidemic. He was driven by musher Gunnar Kaasen, who worked for Leonhard Seppala. Seppala had also
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,