For the first time in the history of the world's most famous sled dog race, several of the high-performance animals have tested positive for a prohibited drug. But race officials have refused to name the musher involved.

Dallas Seavey won his third straight Iditarod Trail Sled Dog Race early Tuesday morning.

Much of the start of the world's most famous sled dog race is covered in barren gravel, forcing Iditarod organizers to move the start further north where there is snow and ice.