Unlike the dog’s body, the pads of its paws are not covered with fur, which would serve as insulation from the cold.
The thin fat layer is also not able to perform this function – the surface area of the pad is quite significant, therefore, heat loss is inevitable.
People avoid blood hypothermia in this situation helps the natural defense mechanism – the reduction of the walls of the vessels of the extremities and, as a result, a decrease in blood flow in them. However, we should not forget that by protecting the body from freezing due to hypothermia of the blood in the hands and feet, the limbs themselves are at risk of frostbite.
Scientists from Japan’s Yamasaki Gakuen University conducted a study of the location of blood vessels in the paws of adult dogs. An article detailing their findings was published in the journal Veterinary Dermatology.
As it turned out, the arteries through which blood enters the dog’s paws are equipped with a network of small veins that are countercurrent.
In other words, each artery that carries blood along the pads is accompanied by several venules, through which the blood flows in the opposite direction. This makes it possible to exchange heat between the vessels: heat from the arterial blood is transferred to the venous vessels, which is not dispersed in the external space. As a result, the blood does not cool down and does not cause hypothermia of the body, but the paws do not freeze, because they do not remain without blood supply.
Scientists believe that this discovery makes it possible to say that the distant ancestors of today’s domestic dogs lived in a cold climate, as a result of which they formed this adaptation, which makes it possible to move on snow or ice without consequences. It should be noted, however, that many breeds have lost this useful property during their life near humans, so modern Pets should be restricted from walking in winter.