Cold? No problem!
How do penguins protect themselves from the intense cold?
Take a close look at them. Their compact, stocky bodies mean that they are very efficient at retaining heat. Their necks are short and their feet and bills are the only parts of their bodies not covered with feathers.
In addition, penguins have a number of physiological and behavioural adaptations that help protect them from the intense cold.
First of all, their plumage is very dense — 12 feathers/cm². The middle part of each feather, called the rachis, is flat, so that the feathers can overlap, sort of like the tiles on a roof. This makes them more waterproof.
In addition, penguins have a well-developed oil gland at the base of their tails. They preen themselves using the oil secreted by the gland to make their plumage even more waterproof.
Each feather has little barbules that trap air. This air layer helps the birds preserve energy.
When penguins moult, the new feathers grow beneath the old ones and push them out, so the birds always have the same number of feathers.
There is also the fact that penguins have a thick layer of blubber. These three adaptations (feathers, air and blubber) keep them so well insulated that snow doesn’t even melt when it lands on them!
Penguins also have a highly developed circulatory system that helps to protect their extremities.
Veins and arteries form a counter-current heat-transfer system that keeps their extremities relatively cool without sending cold blood back to the heart that would shock it. (Image: temperature in centigrade)
Breathing frigid air would normally make it difficult to maintain the proper body temperature, but the blood vessels in the mucous membranes of penguins’ nasal passages warm it up as they breathe in.
In addition, like many animals, penguins shiver when they are cold in an effort to generate heat.
Finally, some species of penguins have behavioural adaptations that help them withstand the cold.
Emperor penguins, for example, which reproduce in the middle of winter, huddle together to protect themselves from blizzards.
These huddles may consist of hundreds, if not thousands, of individuals. The birds in the middle gradually move toward the outside, while those on the outside shuffle toward the centre. Sometimes you can even see young chicks practising this behaviour with one another!