The original sled dogs were chosen for their size, brute strength and stamina, but modern sled dogs are generally mixed-breed (‘Alaskan’) huskies who have been bred for generations for their endurance, strength, speed, tough feet, good attitude and appetites, and most importantly their desire to pull in harness and their abilities to run well within a team.

Some kennels still concentrate solely on pure-bred sled dogs, typically Siberian Huskies, Alaskan Malamutes or Canadian or American Inuit Dogs, but the majority of modern sled dogs found in long-distance races are truthfully 'genetic mutts' and the name that is most commonly used to refer to them as a group today is 'Alaskan Huskies'.

Theses modern sled dogs come in many different shapes (or conformations), sizes and a wide variety of colorings; from as small as 35 pounds up to 70 pounds or more. Typically, the modern long-distance Alaskan Huskies weigh between 45 and 60 pounds. Mushers strive for a well balanced dog team that matches all dogs for both size (approximately the same) and gait (the walking, trotting or running speeds of the dogs as well as the 'transition speed' where a dog will switch from one gait to another) so that the entire dog team moves in similar a fashion which increases overall team efficiency. Mismatched teams (large and smaller dogs, different running styles and gaits) can also perform well in long-distance sled dog races, but usually mushers will try to build their teams from sled dogs of similar size, structure and gaits.

Modern Sled Dogs must have good feet. Good canine feet for long-distance sled dogs are typically closely spaced (i.e. toes not spread out or ‘splayed’) and tough (i.e. resistant to both wear and injury). While good feet can be bred for, all sled dogs competing in long-distance races must also be provided with excellent foot care by their mushers. Booties are often worn as a protective covering, this helps the dogs naturally tough feet to cover long distances without difficulties. Extreme cold and new snow can lead to trail conditions that are abrasive to the dogs’ feet and also add more friction to the trail, preventing the sleds from gliding easily. Booties for the dogs are a necessity under these kinds of trail conditions. 

Dogs sweat only through the mouths (panting) and feet, and not through pores of their skin like humans, so there is a constant need for mushers to balance the use of booties for protection with the dogs’ requirements for thermoregulation, or controlling their body temperatures, so mushers remove their dogs’ booties upon arrival at rest stops and when trail condition are good, teams may run without booties to allow their feet to have some breathing room.

Mushers are constantly inspecting their dogs feet all year long and throughout the race, and as a well known mushing expression says, “As go their feet, so go the dogs” meaning that everything rides on the feet of the dogs and even minor issues will lead to trouble if they are not dealt with quickly and effectively by the musher.

Modern sled dogs are canine athletes, and must be very fit to participate in races as demanding as the Yukon Quest. Any dogs that are even somewhat overweight will likely lead to unnecessary soreness as their joints and muscles cannot support the extra strain and effort the additional weight creates. Typically, the early pre-season training runs are very short distances and designed to get the sled dogs back into ‘running shape’ before the more serious training season begins.

Because these sled dogs are so athletic, many people seeing long-distance sled dogs for the first time are amazed by how small or thin they look; but in fact they are in excellent physical condition much like an Olympic marathon runner would ‘appear thin’ the day before their main race and compared to someone who never exercises, they would appear ‘too small’ at any time of year!

Modern sled dogs must also possess good fur, with an undercoat that insulates them from the cold temperatures where they live and run and an overcoat (also called a ‘guard hair coat’) that prevents the build-up of ice and snow in windy and cold conditions. With changing climatic conditions in the North, some years’ warmer weather can present challenges to these well-coated dogs, and mushers must take extra measures to prevent their heavier-coated dogs from overheating on warmer winter days.

Another important quality that musher looks for in their sled dog is how well they eat. From a young age, when the dogs are still pups, mushers will try to impart good eating habits with their dogs. Picky eaters tend to become more picky out on the trail or when weather conditions turn colder. Mushers look for dogs that eat with enthusiasm all the time, regardless of weather conditions of if they are tired. This way, their dogs eat well during training and on the race so that they can consume a sufficient amount of calories to be able to keep themselves warm while running and resting, even at extremely cold temperatures, and also be able to perform to their maximum abilities during the race. Just like people, if you are hungry, it’s more difficult to do what you can do than if you are well fed.

Finally, mushers look for sled dogs that love to run in harness, work well in a team with other sled dogs, and who get along well with the musher and have that ‘special bond’ that is at the core of great dog teams and their mushers. Although all the physical traits are necessary for sled dogs to be able to complete at the level of the Yukon Quest, it is often said that, “Attitude is Everything” and some dogs with lesser physical abilities, just like some less-talented human athletes, can often become superstars because of their tough mental attitude towards both life and the world of competition. The best modern sled dogs are well-bred, raised with care and love and are energetic and eager to please their musher.