Here are some other key things to know about the four-legged competitors:
IT TAKES A TEAM
Mushers must have 12 to 16 dogs at the starting line. They must have at least six of those dogs to finish the race. If they don't have enough dogs at the end, too bad. Race rules say no new dogs can be added on the trail.
YOUTH VS. WISDOM
Most Iditarod dogs range in age from 2 to 7, but some dogs as young as 1 ½ and older than 9 have participated. With a good mix of ages, mushers get frisky youngsters and seasoned veterans. It's the older dogs that have come to memorize the trail. "Like, once a guy's been in the NBA finals, he knows it," race marshal Mark Nordman said.
SUPER CALORIE BURNERS
Oh, to have the metabolism of an Iditarod dog. These are not huge animals, generally ranging from 35 to 55 pounds. Yet each sled dog burns through at least 10,000 calories on the trail, continually snacking besides the three squares a day.
CANINE TRAIL MIX
The Iditarod diet used to be heavy on meat and fish, with some kibble thrown in. But the past decade has seen a reversal. Where it was once a combination of about 30 percent commercial dog food and 70 percent meat and fish, it's now the opposite for many teams, thanks to the development of increasingly high-quality commercial dog food. "It's why the pet industry has enjoyed the race so much, because they learn so much from the dogs that they can pass it on to the general community of pets," Nordman said.
DOG TEAM VITALS
Some dogs still die during the race, including a dropped dog that died of asphyxiation at a checkpoint last year after it was covered by snow from a severe storm. But dog deaths slammed by animal rights activists over the years have dramatically declined. Last year's death was the first since 2009. Dog care is a huge focus, with an average of six veterinarians assigned to each checkpoint to assess the animals' health through such indicators as heart rate, hydration and appetite. Warning signs vets look for include off-kilter gaits and attitudes.
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