These remarkable little creatures can pull a sled 100 miles at a stretch, eat some raw meat, take a four-hour nap and then start happily barking at the chance to race 100 more miles.
Do they have some secret for endurance that humans don’t have?
They do, according to Michael Davis of Oklahoma State University’s Center for Veterinary Health Sciences. For the past ten years he has studied sled dogs. This week he will present his findings at a conference of the American Physiological Society.
In his study Dr. Davis found that sled dogs, like human athletes, show body damage during their first day of exercise. Bits of muscle enzymes and proteins leak from the cells, a sign of cell damage. Cells of human athletes recover in a day or so, but when they go for another run, the same damage happens all over again.
For sled dogs this is not the case. He explains in Live Science:
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.
Sled dogs can somehow reprogram their bodies after the first or second day of training with a sort of “athletic armor” to prevent further bodily stresses.
Their feats take a large number of calories. The dogs who typically weigh around 55 pounds eat 12,000 calories a day. To compare, Michael Phelps also eats 10,000 to 12,000 calories a day during competitions, but Phelps is three times the weight of the sled dog.
Four time Iditarod winner Martin Buser estimates the annual cost of feeding his 50 dogs is $55,000.
To get the necessary calories, the dogs are fed a diet high in fat. Fat has a higher concentration of calories than protein or carbohydrates. Humans who eat a diet high in fat often become obese and develop type 2 diabetes. According to Dr. Davis, finding out what allows the sled dogs to eat so much fat and stay healthy could benefit humans.
More information from Live Science
At one time Poodles were used as sled dogs and Poodles ran in the Iditarod.