Pat Moon and his team travel the Kuskokwim River toward McGrath, Alaska, during the Iditarod Trail Sled Dog Race on March 7. (Marc Lester/Anchorage Daily News/Associated Press)
Sled dogs look on before hitting the trail at the official re-start of the 40th Iditarod Trail Sled Dog Race in Willow, Alaska on March 4. (Wayde Carroll/Reuters)
Aliy Zirkle laughs at the finish line of the Iditarod Trail Sled Dog Race in Nome, Alaska, on March 13. Zirkle placed second. (Marc Lester/Anchorage Daily News via Associated Press)
A leader in Pat Moon's dog team tugs at its harness during the official start of the Iditarod Trail Sled Dog Race in Willow, Alaska on March 4. (Bill Roth/Anchorage Daily News via Associated Press)
Two mushers cross the Farewell Burn during the Iditarod Trail Sled Dog Race on March 6 in Nikolai, Alaska. (Marc Lester/Anchorage Daily News via Associated Press)
One of Matt Gilbin's dogs grabs a quick snow snack as they wait for a slower musher to move into the finish shoot at the BLM airstrip along Campbell Creek during the Iditarod Trail Sled Dog Race on March 3 in Anchorage, Alaska. (Richard J. Murphey/Anchorage Daily News via Associated Press)
A musher makes the run between the Ophir and Cripple checkpoints during the Iditarod Trail Sled Dog Race on March 8. Snow machine tracks swirl near the trail. (Marc Lester/Anchorage Daily News via Associated Press)
Scott Janssen, of Anchorage, Alaska, reaches toward fans during the official restart of the Iditarod Trail Sled Dog Race in Willow, Alaska, on March 4. (Bill Roth/Anchorage Daily News via Associated Press)
Fans cheer for mushers on the long trail to Nome at the official re-start of the 40th Iditarod Trail Sled Dog Race in Willow, Alaska. (Wayde Carroll/Reuters)
Dallas Seavey pulls in to the checkpoint in Unalakleet, Alaska, during the Iditarod Trail Sled Dog Race on March 11. (Marc Lester/Anchorage Daily News via Associated Press)
Wolvie and Roscoe stir as Karen Ramstead prepares to feed them in Nikolai, Alaska, during the Iditarod Trail Sled Dog Race on March 7. (Marc Lester/Anchorage Daily News via Associated Press)
Wade Marrs takes a nap in the Nikolai School during the Iditarod Trail Sled Dog Race on March 6. (Marc Lester/Anchorage Daily News via Associated Press)
Musher Bill Pinkham collects hot water during his stop in Takotna, Alaska, during the Iditarod Trail Sled Dog Race on March 7. (Marc Lester/Anchorage Daily News via Associated Press)
Musher Colleen Robertia looks at Quigley as she prepares to leave the checkpoint in Nikolai, Alaska, during the Iditarod Trail Sled Dog Race on March 6. (Marc Lester/Anchorage Daily News via Associated Press)
DeeDee Jonrowe leaves the checkpoint in Nikolai, Alaska, during the Iditarod Trail Sled Dog Race on March 6. (Marc Lester/Anchorage Daily News via Associated Press)
Karin Hendrickson embraces her team leader Hatchet in Takotna, Alaska, during the Iditarod Trail Sled Dog Race on March 8. (Marc Lester/Anchorage Daily News via Associated Press)
A team competing in the Iditarod Trail Sled Dog Race heads into the Finger Lake checkpoint on March 5. (Marc Lester/Anchorage Daily News via Associated Press)
Sonny Lindner cooks dog food at the Ruby, Alaska, checkpoint during the Iditarod Trail Sled Dog Race on March 9. (Marc Lester/Anchorage Daily News via Associated Press)
Iditarod communications volunteers Angie Taggart (standing) and Keri Koger update the race standings in Nikolai, Alaska, during the Iditarod Trail Sled Dog Race on March 6. (Marc Lester/Anchorage Daily News via Associated Press)
Aliy Zirkle feeds her dog team in Unalakleet, Alaska, during the Iditarod Trail Sled Dog Race on March 11. (Marc Lester/Anchorage Daily News via Associated Press)
A musher crosses Norton Bay and heads into Koyuk, Alaska, during the Iditarod Trail Sled Dog Race on March 12. (Marc Lester/Anchorage Daily News via Associated Press)
Dallas Seavey holds his leaders, Diesel, left, and Guiness after he arrived at the finish line to claim victory in the Iditarod Trail Sled Dog Race in Nome, Alaska, on March 13. Seavey is the youngest musher to win the nearly 1,000-mile race across Alaska. (Marc Lester/Anchorage Daily News via Associated Press)
A musher rides his dog sled during a stage of the Sedivackuv Long dog sled race in Destne v Orlickych horach on Jan. 26. Each year, racers from all over Europe arrive to the village of Destne in the Orlicke mountains of the Czech Republic to take part in the race series. (Petr Josek/Reuters)
A musher and his dogs seen in a long exposure compete on a track near the Mont-Cenis Path during the ninth stage of La Grande Odyssee sled dogs race on Jan.17. The race crosses the Alps in France covering over 1000 km (621 miles) over 11 days. (Denis Balibouse/Reuters)
Rookie Marie-Anick Alie of Inukvik, Northwest Territories, rounds a corner near Goose Lake on the final day of the Anchorage Fur Rendezvous World Championship Sled Dog Race on Feb. 26. (Bill Roth/Anchorage Daily News via Associated Press)
A view of mushers as they prepare their dogs at the Polar Base at sunrise before the second part of the seventh stage of La Grande Odyssee sled dog race in Mont-Cenis on Jan. 15. The race crosses the Alps in France covering over 1000 km (621 miles) over 11 days. (Denis Balibouse/Reuters)
A musher greets his dog during a break in a stage of the Sedivackuv Long dog sled race in Destne v Orlickych horach on Jan. 26. Each year, racers from all over Europe arrive to the village of Destne in the Orlicke mountains of the Czech Republic to take part in the race series. (Petr Josek/Reuters)
Charles-Antoine Saucier competes during the Quebec Winter Carnival dog sled race in the streets of Old Quebec in Quebec City on Jan. 28. (Mathieu Belanger/Reuters)
A siberian husky is ready to start at the sled dog race in Schoeneck, eastern Germany on Jan. 28. (Hendrik Schmidt/AFP/Getty Images)