How Siberian Huskies are built for cold and long distances

The Siberian Husky was bred to pull light loads at moderate speed over long distances in the Siberian winter, and almost every trait that helps it in the cold makes it harder to keep in a warm house. The Kennel Club traces the breed to northeast Siberia, where it was known as the Chukchi sled dog after the people who used it for long-distance hauling. Its thick coat, its efficient trot and its appetite for work all come from that job.

The double coat

A husky's coat has two layers. The undercoat is soft, dense and short, and it traps a layer of still air against the skin. Snow can settle on a well-coated husky without melting, because so little body heat escapes through the fur. The outer guard hairs are longer and coarser. They shed snow and rain and protect the undercoat from wind.

Huskies shed the undercoat heavily, usually once or twice a year, in what owners call blowing the coat. For a few weeks the loose undercoat comes out in handfuls. Brushing through to the skin several times a week during a molt removes it before it mats, and the Kennel Club lists the breed as needing grooming more than once a week all year.

Shaving a husky for summer is a mistake. The coat insulates against heat as well as cold, and the guard hairs shield the skin from sun. Some dogs also regrow hair slowly or patchily after clipping. This is known as post-clipping alopecia, and a small veterinary dermatology study noted that it often responds poorly to treatment. Thorough brushing to remove dead undercoat does more to keep a husky cool than clippers do.

Heat exchange in the paws

Paws are the weak point in any dog's insulation. They have no fur on the pads, they touch the snow directly, and small extremities lose heat quickly. An anatomical study of dog footpads found that the arteries supplying the pad are wrapped in a network of small veins that works as a counter-current heat exchanger. Warm blood flowing down towards the pad passes its heat to the cooler blood returning to the body, so heat is recycled to the core instead of being lost to the ground. Other vessels let blood bypass the capillaries, keeping the pad surface warm enough to avoid damage.

That study was done in ordinary dogs, not huskies. The arrangement appears to be a feature of dogs in general, which helps explain why many breeds can walk on snow for long periods. It does not make huskies immune to frostbite or to ice balls packed between the toes. On long winter runs, check the feet for cuts, cracked pads and ice, and consider booties for dogs that run on crusted snow or salted roads.

What sled dog research shows about endurance

The best-known studies of endurance in dogs were done on Alaskan sled dogs, a working type bred for racing that often includes Siberian Husky ancestry but is not the same breed. The findings describe what conditioning can do in a dog built for distance, not a special trait of every pet Siberian.

In one study, conditioned sled dogs ran 160 km a day for up to five days on a high-fat, low-carbohydrate diet. Glycogen, the carbohydrate store in muscle, fell sharply after the first day's run. After the second day it had recovered to more than half of resting levels and stayed there, despite the dogs running every day. The authors credited the dogs' muscles with a strong ability to restore glycogen, but left open whether it came from rapid rebuilding during the short rest periods or from the muscles switching to other fuels.

Later work changed the picture of how these dogs fuel themselves. A review of the research on ultra-endurance sled dogs concluded that, although racing diets supply most of their energy as fat and protein, the dogs rely mainly on glucose as fuel while they run, and conditioning adapts their bodies to keep that glucose supply going. During week-long races their total energy use is very high, and racing diets are built around it.

Curling up against the cold

A resting husky in the snow typically curls into a tight ball with its bushy tail wrapped over its nose and feet. The position reduces the surface area exposed to cold air and covers the parts of the body with the thinnest fur. The tail over the face also shelters the nose from wind. It is a behavior worth allowing for at home: huskies kept outdoors in winter need a dry, draft-free shelter with bedding, not just a thick coat.

Bred for distance

The Chukchi used their dogs for long-distance hauling, and the breed still shows it. The Kennel Club calls the Siberian Husky the lightest and fastest of the sled dogs. Their natural gait is a smooth, ground-covering trot. They were bred to work in teams, and they are often sociable with other dogs, though many have a strong prey drive towards cats and small animals.

The Kennel Club places the breed in Breed Watch Category 2, which means it has points of concern for health and welfare. Its minimum advice for breeders is eye testing under the BVA/Kennel Club/ISDS Eye Scheme and attention to genetic diversity. Hip scoring for hip dysplasia is listed as best practice. Puppy buyers should ask to see both parents' eye certificates and hip scores.

The 1925 serum run to Nome

In January 1925 a diphtheria outbreak threatened the town of Nome, Alaska. With the town cut off by winter, antitoxin serum was carried the last stretch by dog sled. According to the Central Park Conservancy, twenty teams relayed it almost 1,100 km (700 miles) in blizzard conditions and temperatures of about -34°C (-30°F), finishing in five days and seven hours. Balto led the final team into Nome through some of the worst weather of the whole run and became its public face. Frederick Roth's statue of him was unveiled in Central Park in December 1925. He was one of many dogs across those twenty teams.

Caring for a husky today

• Exercise. The Kennel Club puts the breed in its highest band, more than 2 hours of exercise a day. Running, canicross and bikejoring suit huskies well in cool weather. A bored, under-exercised husky tends to dig, howl, chew and escape.
• Heat. In warm weather, exercise at dawn or late in the evening, keep sessions shorter, provide shade and water, and stop at heavy panting or slowing down. A dog that staggers, collapses or vomits after exercise in heat needs cooling with water and urgent veterinary care.
• Food. Feed to body condition, not to the breed's reputation. A family husky does not have a racing sled dog's workload, and many put on weight if they are fed as if they did. The ribs should be easy to feel under the coat.
• Fencing and recall. Many huskies are escape artists with limited recall. Secure fencing and a long line in open country keep them safe.
• Mental work. Scent games, food puzzles and short training sessions help a clever, independent dog settle.

Sources

1. Siberian Husky. The Kennel Club, Breeds A to Z.
2. A small scale study to evaluate the efficacy of microneedling in the presence or absence of platelet-rich plasma in the treatment of post-clipping alopecia in dogs. Veterinary Dermatology, 2020.
3. Functional anatomy of the footpad vasculature of dogs: scanning electron microscopy of vascular corrosion casts. Veterinary Dermatology, 2011.
4. Recovery of muscle glycogen concentrations in sled dogs during prolonged exercise. Medicine and Science in Sports and Exercise, 2005.
5. Glucocentric metabolism in ultra-endurance sled dogs. Integrative and Comparative Biology, 2021.
6. Balto statue. Central Park Conservancy.