Arctic abilities
What our polar breeds have in common is that they must have characteristics that make them suitable for surviving in an arctic climate. Ingvild Svorkmo Espelien (geneticist and breeder of working Samoyeds in Norway, kennel Vinterskogen) describes the difference between the abilities and characteristics of an arctic breed and other bredds as follows.
"Archic/polar properties. this is a common superstructure for all arctic breeds. Their function is actually primarily to be able to survive in polar regions. next comes traits/working characteristics. that is the big difference compared to alaskan huskies, who are very good sleddogs, but have uneven/poor polar characteristics. an example is snow. We never give water to our Samoyeds on trips in the winter or at the cabin. they eat snow and it works out for them. On races, something else happens, then we give water because they rest little. As a rule, Alaskan huskies cannot survive on snow. I could also mention the thickness of the skin, fur on the belly and ears, etc. Aktic characteristics must be followed carefully, and they are shown by the dogs being allowed to live outdoors in acric conditions in the winter - and indeed also in the summer. Samoyeds tolerate mosquitoes and other biting insects very well, and they tolerate much more heat than people realise."
Above: Greenland dogs working in snow.
Adaptations for Cold Environments
In cold environments mammals and birds use two major mechanisms to maintain homeothermy: (1) decreased conductance, reduction of heat loss by increasing the effectiveness of the insulation, and (2) increased heat production.
Many animals whose limbs are exposed to cold temperatures have counter-current heat exchange mechanisms to allow the tips of the extremities to be cold without cooling down the whole body, thus minimizing overall heat loss
In all mammals living in the cold regions of the earth, fur thickness increases in winter, sometimes by as much as 50%. Thick underhair is the principal insulating layer, whereas the longer and more visible guard hair serves as protection against wear and for protective coloration. However, unlike the well-insulated trunk of the body, the body extremities (legs, tail, ears, nose) of arctic mammals are thinly insulated and exposed to rapid cooling. To prevent these parts from becoming major avenues of heat loss, they are allowed to cool to low temperatures, often approaching the freezing point. The heat in the warm arterial blood is not lost from the body, however. Instead, a countercurrent heat exchange between the outgoing warm blood and the returning cold blood prevents heat loss. Arterial blood in the leg of an arctic mammal or bird passes in close contact with a network of small veins. Because arterial blood flow is opposite to that of returning venous blood, heat is exchanged very efficiently from artery to veins. By the time the arterial blood reaches the foot it has transferred nearly all of its heat to the veins returning blood to the body core. Thus little heat is lost from poorly insulated distal regions of the leg to the surrounding cold air. Countercurrent heat exchangers in appendages also are common in aquatic mammals such as seals and whales, which have thinly insulated flippers and flukes that would be avenues of excessive heat loss in the absence of this heatsalvaging arrangement.
Above: Countercurrent heat exchange in the leg of an arctic wolf. The upper diagram shows how the extremities cool when the animal is exposed to low air temperatures. The lower diagram depicts a portion of the front leg artery and vein, showing how heat is exchanged between arterial and venous blood. Heat is shunted back into the body and conserved.
Arctic adaptation for summer
Even the summer in the arctic areas becomes really hot in some places, which affects the animals' need to readjust and adapt to living in the heat. One of the most important polar characteristics linked to the summer months is our dogs' ability to shed properly. The correct shedding means that the dogs let go of all the undercoat and then put on a short and sparse undercoat over the summer. A dog that lacks the ability to shed all its undercoat will have a hard time during the summer months, risking moisture eczema and overheating. A dog without verbal shedding should not be taken to the mountains during the summer and carry a backpack. This is something the show judges should attach great importance to when judging our breeds during the summer months and remember that a dog with full winter wool is a fault in the arctic adaptation.
Above: An example of a Samoyed in correct summer fur.