Watching TV programs about Antarctica, the homeland of penguins, many are wondering how these birds manage to live and reproduce in such unfriendly conditions. And a shiver goes through the body as the camera captures the naked paws of the penguins huddled together on the icy shore. Why aren't their limbs freezing?
For a long time, scientists from many countries have tried to find an answer to the question of why penguins do not freeze their paws. It turned out to be surprisingly simple. The limbs of this bird are already cold! Their temperature is slightly above zero degrees. Touching snow or ice, they do not cool down, as they are not at all warm by themselves.
Why are the naked paws of a penguin so cold? Everything is explained by their special structure. Ornithologists have found that there are a huge number of blood vessels in the feet of this bird. And between the veins and arteries located there, there is a constant heat exchange. The cooled venous blood rises from the paws up to the body of the penguin, warming up along the way. This is very important, because if the blood reached the body, keeping the temperature low, the bird would simply freeze, despite its thick and dense plumage. And arterial blood, on the contrary, descends to the lower extremities, cooling down along the way, warming the body. When she reaches her paws, her temperature approaches zero. This phenomenon is called "reverse flow". It not only helps the bird to survive in the frosty Arctic winters, but also allows it to maintain the ability to move. After all, if the penguin's paws were warm, they would freeze to ice.
In addition, penguins retain heat not only in their paws, but throughout the body by slowing down blood flow. During a strong drop in air temperature, they huddle in flocks and try to move as little as possible. By periodically changing places, they allow the birds on the edge to keep warm inside the group of companions. The body of penguins at this time enters a state similar to that which occurs in animals that hibernate - bears, marmots, turtles. However, this state is less deep, and, in case of danger, the penguins quickly come to their senses and have time to react.
