The penguin is the only bird on the planet that feels as good as a fish in the water, but absolutely cannot fly. Of all modern birds, only penguins move "standing". But of particular interest is their ability to survive in one of the most unfavorable places on Earth - Antarctica. The average annual temperature in the South Pole area is only -49, 3 degrees Celsius, and a record low -89 degrees. Add to this the wind, the speed of which sometimes reaches 100 m / s, and we get conditions in which, it would seem, it is simply impossible to survive.
Nevertheless, the entire coastal part of the mainland is inhabited by huge emperor penguins and adélie penguins. These birds spend most of their lives in the sea, sometimes plunging up to five hundred meters deep into the icy water, where even the sun's rays do not penetrate.
Nature took care of their survival, providing them with a unique thermoregulation mechanism. The penguin is kept warm in such harsh conditions by a fat layer up to 3 cm thick, above which there are three layers of waterproof feathers that evenly cover the entire body of the bird.
Such a "suit" is reliably protected from getting wet, in addition, the air between the feathers allows you to keep warm both in the water and in the open, blown space. During molting, penguins shed a large number of feathers at the same time and at this time are not able to swim in water and remain without food until new feathers grow.
The heat exchange in the only open parts of the penguin's body - the feet - deserves special attention. Amazing! Without sufficient protection, the paws of birds do not freeze, allowing them to stand in the cold for hours or swim in icy water. Reducing heat loss saves them from freezing: hot arterial blood in the paws of penguins gives up its heat to the counter flow of venous blood and thus cools. This effect is achieved due to the unusually close mutual arrangement of arteries and veins and is called the principle of backflow.
The temperature of the feet of a chinstrap penguin is usually about 4 degrees, which not only helps to retain heat, but also allows you to move freely on the ice. But warm paws would surely melt the ice and freeze into it.
The warmest penguin habitat is the Galapagos Islands, located at the equator. They definitely do not freeze there :)