How to

17 June 2016

How They Keep Warm: Penguins

Life exists on a larger scale in the Antarctic, even where the birdlife is concerned. Penguins do exist elsewhere, but nowhere are they more abundant than in the Antarctic. They’re also bigger there than they are anywhere else, even the lightest variant, the rockhopper, weighs in at more than 2.5kg. Emperors are the largest, and adelies are the most common.

The largeness is by design, it’s one of the myriad of adaptations they use to keep warm in the famously punishing winter months. Antarctica is the coldest place on Earth, and penguins are some of the only native land animals who don’t hibernate during the winter months, when wind speeds can often be in excess of 40kmh, and temperatures often drop well below -40°C. It is, indisputably, one of the harshest climates on the planet, and penguins have all but conquered it.

Aside from their size, penguins also sport the same kind of sub-cutaneous blubber as other mammals which live in similar conditions. Their downy feathers work well at keeping more warmth in on land, but penguins spend a great deal of their daily activity in the water, hunting. Their feathers are actually designed to deal with this, as they have a layer of woolly down, can flatten to streamline them and come apart again to shed water without losing precious heat. If you’ve ever seen penguins shaking themselves around to ruffle their feathers, it’s more than just an endearing affectation (although it is indeed adorable), it’s a way of puffing the feathers out to trap heat more effectively.

Of course, they aren’t completely covered with feathers – their feet and flippers are exposed, but they have a rather impressive way of accounting for this. There aren’t actually any active muscles within penguin’s feet or flippers; it’s all just tendon which is controlled by muscles deeper in their legs and chest, where it’s warm. In this way, they never seize up, and can operate at the same capacity regardless of temperature. That being said, the outer extremities are never allowed to dip below freezing, delicate control of blood flow takes care of that.

Of course the most effective, most famous method they use to keep warm is entirely behavioural – they huddle. During the coldest months, colonies will bunch together in very tight groups to conserve body heat, each individual alternating between the warm, comfortable inner reaches, and walking around the cold perimeter so that all of them get a fair share of the warmth. There’s more to it than that, though, as every 30-60 seconds all the penguins will shuffle their feet, creating a kind of Mexican wave effect which can restructure the huddle, preventing any of them from getting crushed or trampled.

The last, perhaps most important step is storage of food energy. With emperors, the female will make straight for the sea after mating, spending months building up a huge fat reserve while the male stays with the egg, keeping it warm in the huddle with a special blubbery pouch which folds over the egg to keep it protected. When the female gets back, he will have dropped in weight by anything up to 40%, and even when the swap is made the males have to travel for somewhere in the region of 115 days and hundreds of kilometres before he can actually start eating to fatten back up.

For these reasons, penguins are some of the most resilient animals on the planet. They’re keen hunters, have a myriad of defence measures against their own predators and can deal with cold better than perhaps any other animal of their size. 

Callum Davies

Callum is a film school graduate who is now making a name for himself as a journalist and content writer. His vices include flat whites and 90s hip-hop.