With their small body mass, why don't penguins freeze while they sleep?

Question

With their small body mass, why don't penguins freeze while they sleep?

Answer 1

They are not that small since they are about the size of a ten year old child with a large chest at 30 kg (66lb) even the Rockhopper is 2.5kg (5.5lb). This is large enough to supply adequate metabolic heat to survive the winter extremes each species experiences.

Emperors withstand the most extreme conditions with several adaptations beyond being larger.
In the coldest conditions, penguins sit supported on a tripod of two feet, rocked back on their heels to minimize contact & reduced blood flow, and a stiff tail that they lose no heat through because only feathers touch the ice.
Sea water only gets to -1.9°C (25.8°F), after that it would be solid and the birds would have more problems than cold. In the water it is blubber that keeps them warm just as it does for other sea mammals. On land the feathers are additional insulation with a special fluffy down under the outer water proofing feathers. Like any bird they fluff to increase insulation.
They have countercurrent circulation in their extremities, flippers & feet, where they loose most heat. The veins & arteries lie in close contact so heat is passed out of the warm, outgoing blood across to the returning chilled blood. They also reduce blood flow here in the coldest temperatures keeping their feet just above freezing. They have their muscles within their body cavity. This allows them to operate feet & flippers by tendons at a distance while keeping the vulnerable muscles warm.
When they get to warm they cool off by increasing blood flow to their extremities.

Answer 2

Penguins have the below mechanisms to cope with the cold -

*waterproof (of sorts) feathers, to insulate against the cold water/snow/ice etc
*decent layer of fat just under skin surface to further insulate them
*very social, group instincts to huddle, with constant rotation so so all get protection at some stage

and... most interesting...

the blood vessels ni a penguins legs and feet are purpose built for the weather. the soles of their feet are really tough and leathery and also have a fat layer for insulation and barely any blood vessels. then the vessels in their legs actually have the veins and arteries running side by side, very closely, with some smaller vessels possibly running in between. The idea is that heat is lost from the body through the feet - in contact with ice, so heat is lost as blood runs down to the feet. So with the position of their blood vessels, heat is actually transferred from the 'warmer' arteries into the 'cooler' veins returning the cooler blood back to the heart.　This way a penguin's feet are actually already at a cooler temperature to their body so less heat is lost to the environment and more is retained. from memory i think its something like 4 degrees C is the difference in temp, but thats purely on memory from a long time ago!

There is a name for this, which is also sketchy in my memory... its either counter something or cross something circulation. but i remember being introduced to it in biology and studying it in penguins!

Answer 3

most likely the amount of fat or blubber under the skin and the way the feathers lay for insulation also emperor penguins rotate in a circular mass taking turns in the middle to keep warm

Answer 4

Penguins pass relatively on the factor of floor, this manner to their ft, to maintain their ft heat. thinking, their ft are in basic terms bones and harden leather-based, there's no longer lots tissue to create a gangrene on their ft. They sleep at an identical time as they stand as a results of fact this manner the warmth loss is minimized.

Answer 5

penguins huddle up close to keep warm the warmest ones in the middle make their way to the edges so the ones on the edges get to go to the middle and so on