How Does the Iditarod Race Work? (LiveScience.com)

Each March, the Lance Armstrongs of the canine world take to the mountains with their sled drivers, or mushers, in the world's longest sled race.

Called the Iditarod Trail Sled Dog Race, the event begins in Anchorage, Alaska, and ends in Nome on the western Bering

Sea coast. Teams of 12 to 16 dogs and their musher cover over 1,150

miles (1,850 km) in about 10 to 17 days. Each dog has a microchip, about the size of a grain of rice,

inserted beneath its skin to help race organizers keep track of so many dogs

over the lengthy race.

Cold-loving dogs

The dogs often trek through heavy blizzards and endure temperatures as

low as minus 40 degrees Fahrenheit (minus 40 degrees C).

The treacherous terrain and chill might do in your average pup, but not these sled dogs, which are not

all purebred Siberian Huskies, but mutts, with a mix of

Husky, Alaskan Malamute, Pointer and other breeds.

Michael Davis of Oklahoma State University's Center for Veterinary

Health Sciences has studied the sled

dogs for the past 10 years. He runs check-ups on the dogs before

and after races as well as during controlled experiments for which he

sets up races with groups of sled dogs. The secret to the dogs' feats of

day-to-day endurance lies in their ability to "reprogram" their bodies'

responses to stress after just one day of competition, something humans

can't do.

Ultra athletes

Davis found that just like human athletes, conditioned sled

dogs show body damage during their first day of exercise.

For instance, when any athlete, canine or Homo sapiens, pounds

the pavement or icy ground for miles, bits of muscle enzymes and

proteins leak out from their cells. Scientists say this is a sign of

cell damage. Our cells do recover in a day or so, but as soon as we go for another

run, the same damage happens all over again.

For sled dogs, that's not the case. "If you then take them out and do

exactly the same exercise the following day and the day after that, and

the day after that, you don't continue to get that leakage [of enzymes

and proteins]," Davis told LiveScience.

He added, "In the course of just a day or two, they manage to adapt

their system so that exercise that was injuring a muscle cell here and

there on the first day is no longer injuring muscle cells."

Davis found the sled dogs somehow reprogram their bodies after that

first or second day of training with an athletic armor of sorts to

prevent other bodily stresses as well.

Hungry canines

The four-legged

fur-balls also have appetites rivaling any human athlete. During

race season, the dogs, which weigh a mere 55 pounds (25 kg), consume

12,000 calories a day, Davis said.

For comparison, Olympic swimmer Michael

Phelps reportedly eats some 10,000 to 12,000 calories a day during

competitions. But Phelps boasts at least three times the weight of a

race dog, Davis said.

"The challenge is getting 12,000 calories into a little dog like that

and it has to be very calorie-dense," he said. "While they're racing,

they're eating a diet that is pushing between 60 and 70 percent fat."

(Every gram of fat contains nine calories, compared with the 4 calories

in a gram of protein or carbohydrate.)

Whatever it is that allows sled dogs to chow down on so much fatty food

and stay healthy could be beneficial to humans. And so results of Davis'

findings have implications for humans who have become obese or

developed Type 2 diabetes.

"If you feed a diet that's very high fat to a human, a lot of humans

become obese and they develop type 2 diabetes. And the dogs don't,"

Davis said. "There is no such thing as an obese Type 2 diabetic sled dog

despite the fact that they're eating a diet that should produce that."

Iditarod history

The dogs and their drivers have a long history.

The late Dorothy G.

Page, then chairman of the Wasilla-Knik

Centennial, conceived the idea of having a sled-dog race along the trail

in

1967. She had been intrigued that dog teams could travel over land

(along this

trail) that was inaccessible by automobiles. Two short races were

completed

along part of the trail in 1967 and 1969. The first complete race to

Nome

occurred in 1973.

Soon after, the Iditarod Trail became the major thoroughfare

through Alaska with dog sleds carrying mail, supplies and just

individuals

traveling place to place.

Today the trail is made up of a northern and southern route,

with races alternating between the two on even- (northern) and odd-

(southern) numbered

years. In the early years of the race, mushers only traversed the

northern

trail. But when the board of directors realized the smaller villages

were being

impacted by the race coming through year after year, they decided to use

both

sections.

Here are some past records along the trail:

Sometimes a sled driver can be nipping at the heels of the winner. The closest finish was in 1978 when Dick Mackey finished one second ahead of

Rick Swenson. The winner was decided by the nose of the lead dog across the

finish line.

Taken from here