Just like the world's top athletes, sled dogs also undergo arduous training to hone their iron will and strong physique. Sultana is such an excellent sled dog. Her genes give her a love for running, a passion for work and super adaptability to the wild environment. So you won’t see them in the training ground. The sled dogs are trained on the spot in the severe cold environment of ice and snow, and grow up in battle. In Alaska's Denali National Park, they're gearing up for the next working season.

Eight-year-old Sultana is the leader among sled dogs. (Photo taken in Denali National Park, Alaska)

A large wave of work is challenging sled dogs around the world. A large amount of materials for work and travel require the help of sled dogs. International events such as the Alaska Iditarod Sled Dog Race and Yukon Sled Dog Sports also attract about 1,300 sled dogs and thousands of people from all over the world to the ice and snow city of Alaska.

Contrary to popular belief, Siberian Huskies and Alaskan Malamutes are not workhorses. True Sled Dogs are an unofficial breed of sled dogs bred specifically for racing and handling work. Don't be fooled by their aggressive, ruffian-like faces. This kind of sled dog is hardworking and physically strong. It can pull hundreds of kilograms of cargo through ice and snow-covered areas at a time, like a machine that never needs to rest. It is a good and effective working partner of mankind.

As a sled dog, appearance is obviously not the most important, and pedigree is not judged (please note: this is not a beauty contest). The most important thing is work performance. It doesn’t matter whether the cat is black or white, as long as it can catch mice, it is a good cat. Howard Thompson, who now specializes in sled dog breeding in Wisconsin, said: "You must have a belief, which is the spirit of being at home all over the world. You feel that the scenery is always elsewhere. Only in this way can you keep running."

"Then, the sled dog must have a good appetite and must not be picky about food, no matter when and where." Long-distance treks in severe cold environments consume a lot of physical energy. Sled dogs like Sultana are often required to cross as long as 483 Kilometers and even further arduous tasks. It can take anywhere from a few days to a few weeks to complete such a task, and there is no room for being picky about food while sleeping in the open air.

"Sled dogs must have a strong body, especially claws that are as indestructible as steel." Charlotte Mooney, who is engaged in sled dog breeding in Montana, added. When competing, we can use professional tools (similar to human boots) to protect the sled dog's paws. But this will greatly slow down the running speed of the sled dog. It is also not applicable to such short-distance items.(shorter than 48 kilometers). You know, they run at lightning speed.