ANCHORAGE, Alaska – Musher Nicolas Petit lost a huge lead in the Iditarod Trail Sled Dog Race on Monday when his dog team refused to keep going after he yelled at one of the animals.

A dog named Joey had been fighting with another dog on the team and jumped it during a break on the way to the Bering Sea checkpoint of Koyuk.

“I yelled at Joey, and everybody heard the yelling, and that doesn’t happen,” Petit told the Iditarod Insider website. “And then they wouldn’t go anymore. Anywhere. So we camped here.”

Several mushers passed Petit’s team on the trail, erasing his five-hour lead in the race. Pete Kaiser of Alaska was the first musher into Koyuk, followed about an hour later by defending champion Joar Ulsom of Norway.

Musher Peter Kaiser of Bethel, Alaska, leads his team past spectators during the ceremonial start of the Iditarod Trail Sled Dog Race in Anchorage, Alaska, in 2015. Kaiser passed the leader and was the first musher to reach the checkpoint in Koyuk on Monday. Associated Press/Rachel D’Oro

The checkpoint is 827 miles into the 1,000-mile race across Alaska.

Petit said his dogs are well-fed, and there’s no medical issue keeping them from getting up and running.

“It’s just a head thing,” he said. “We’ll see if one of these dog teams coming by will wake them up at all.”

People for the Ethical Treatment of Animals took issue with Petit’s reasoning.

“It’s not the dogs who need to have their heads examined – it’s anyone who supports this merciless race. Illness, injury, or fatigue likely prompted Nicolas Petit to drop four dogs from his team, forcing the remaining 10 to work even harder before they gave up altogether, which he blamed on ‘just a head thing,’ ” PETA Executive Vice President Tracy Reiman said in a statement.

“In the face of hundreds of exhausting miles of ice and snow along the Iditarod, now even the dogs are joining PETA in protesting this cruel race,” Reiman said.

But Libby Riddles, the 1985 Iditarod champion and the first woman to win the race, said the incident demonstrates why dog mushing is a fine art. It requires a balance between being competitive and keeping the dogs happy.

“People have this idea that you can force these dogs to Nome,” she said in a phone interview. “It’s not like that at all.”

“The amount of intuition and communication and trust and experience you have with your dogs is how it all happens and comes together, and Nic Petit happens to actually be one of the best in the business at this,” Riddles said.

Riddles been involved with mushing for 40 years and said she could live 20 lifetimes and not learn everything. But if the dogs get unhappy, they can quit on you, she said.

“Sometimes all it takes is just this one sour grape in the team,” Riddles said. “One dog that has a bad attitude, and it infects the whole rest of the team.”

Huskies in some ways are more primitive than other dogs, she said. Mushers are dealing with their pack mentality.

“It’s like a wolf. Things happen over food. Sometimes if they think a dog is a little wimpy, when they’re crabby, they might want to pick on it,” she said.

Petit will learn from the experience and rebuild, she said.

“I think Nic is handling this pretty well, actually. I think he wants to make sure to preserve a good mental attitude with these dogs for the rest of their careers. That’s what he’s looking at – not just today’s race,” Riddles said.

For Petit, it’s another bad memory from the stretch between the Shaktoolik and Koyuk checkpoints.

He was in command of last year’s race when he got off trail during a blizzard and lost the lead. He wound up finishing second behind Ulsom.

“Something about right here, huh?” he mused.

The race started March 2 in Willow, just north of Anchorage. The course through the Alaska wilderness took mushers over two mountain ranges and the frozen Yukon River before they reached the treacherous Bering Sea coast.

The winner is expected to come off the sea ice and mush down Nome’s main street to the finish line sometime in the middle of the week.