The world-famous Iditarod sled dog race began on Monday in Fairbanks, Alaska, after poor snow conditions forced organisers to reroute the 1,000-mile journey from its traditional start in Willow.
Aaron Burmeister reclaimed the lead on Saturday after leaving the Nulato checkpoint ahead of four-time winner Jeff King. Burmeister, 39, has not yet taken his mandatory eight-hour layover, unlike King.
Aliy Zirkle, aiming for her first win after three consecutive second-place finishes, has also checked in at Nulato. If she wins, she would be the first female champion since Susan Butcher in 1990.
Rounding out the top five are Jessie Royer and Dallas Seavey. Two mushers scratched on Saturday, citing the welfare of their dogs, and two dogs have died, including one on Lance Mackey's team.
Norwegian rookie Thomas Waerner was photographed preparing his team under the northern lights, while mushers were seen massaging dogs' paws and applying ointment at checkpoints.
