For the last time in his 32-year mushing career, Mark Black will run what many say is the toughest dogsled race in the country.

Sunday at noon, Black will start the 27th John Beargrease Sled Dog Marathon (, along with 30 other mushers from throughout North America. For four days he'll will his 48-year-old body and his 14 sled dogs across 390 miles of frozen wilderness stretched along the North Shore of Lake Superior. He'll run day and night, starting in Duluth, heading north toward Grand Marais and back.

It's a trail that Black, who was born and raised in Duluth, has raced 15 times -- more than any other musher in Beargrease history.

Standing 6-6 and weighing 250 pounds, Black has become a Beargrease race institution. Every time he has finished the race he's placed in the top 10, and he won it in 2005.

"He has a presence," said race coordinator Pat Olson. The Beargrease purse this year is $35,000.

"You get used to seeing him, and it's sad to think he's not going to be there."

Black got his first taste of dogsled racing as a sophomore in high school. He borrowed a few dogs, including a German shepherd that served as a guard dog at his dad's marina, and ran a two-day 35-mile race in Wisconsin.

"I couldn't drive [a vehicle] yet, so my grandpa actually brought me down there and dropped me off and said he'd pick me up when the race was over," Black said.

Since then, he's devoted most of his life to dogsled racing. Five years ago he moved from Duluth to a cabin he built himself outside of Grand Marais. He lives with his wife and 32 sled dogs on an 80-acre property accessible only by snowmobile in the winter.

"[Dog sledding] is not a sport, it's a way of life for us," said Black's wife, Mary, who serves as Black's lead handler in races. Mary is also a musher who finished fourth in the Beargrease in 2004.

Black trains his dogs all winter, regularly spending more than eight hours on a sled every day.

The key to winning races, he said, is the dogs. And it's clear Black loves his. During cold winter nights, he wakes up at 1 a.m. to feed his charges fat, and it's not unusual for him to spend $1,000 a month on dog food. Before races, he'll have his lead dogs sleep inside with him.

"A dog is about the most honest thing there is." Black said. "They'll do just about anything that you ask as long as you've prepared them."

Black says that this year his team is stronger than ever. But the Beargrease has a way of humbling good teams and even the most experienced mushers.

"It's the toughest race physically I've ever run," said Black, who has competed in the Iditarod twice. "[Beargrease] is so fast paced."

Seven checkpoints along the trail offer resting and feeding opportunities for the teams. Each musher and dog team must accumulate a race-established minimum amount of rest before finishing the marathon Wednesday in Duluth.

Last year, out of 24 mushers, only six finished. Black has scratched from the race five times. The first time he ran it in 1985, he only made it halfway.

Surprisingly, the tough part about Beargrease is not the distance or the sub-zero temperatures, it's the terrain. The route cuts through the Sawtooth Mountains, which have a peak elevation of only about 1,400 feet. But the constant climbing and descending is brutal on the dogs and their mushers.

"The Beargrease is known for trashing dog teams," Black said.

The unique challenges of the Beargrease attract some of the most prominent mushers in the sport. This year's roster is stacked with the likes of Jason Barron, the two-year defending champion, and Jamie Nelson, an Iditarod regular and a four-time Beargrease winner.

But the grueling terrain that draws other mushers has worn out Black over the years. He can't run up hills as quickly as he once did, and it takes longer for him to recover from runs.

"Everything's gotta end some time," Black said. "I've got over 6,000 miles on my body on the Beargrease trail, and I think that's enough."