It’s not easy to survive in one of the coldest, harshest climates on earth, so how do the six penguin species that inhabit the Antarctic region withstand these fierce, frigid conditions? The answer to this is more than complex but is due to the extensive penguin adaptations over the years that have allowed them to withstand and continue living successfully on this remote, hostile continent.
Penguin adaptations in their feathers
Like any other birds, penguins’ bodies are covered in feathers; however, these feathers are significantly different than those found on other species.
Firstly, penguins naturally carry more genes for beta-keratin protein than any other bird on the planet, enabling them to develop a thick plumage of short, stiff feathers. These feathers don’t only just help them in protecting them during the harsh Antarctic winters when the temperature drops to as low as -30 degree Celsius, but they also keep them waterproof and warm under the water, particularly when swimming in waters as cold as -2.2 degree Celsius.
Secondly, it’s a common misconception that penguins are able to keep warm due to their high density of feathers. Instead, it is the combination of different types of feathers which is most effective at protecting them from the freezing cold.
For example, penguins have adapted a range of different feather types, These include the main quill-like feathers called contour feathers that cover their bodies, as well as two types of insulative feathers: plumules (downy feathers attached directly to the skin) and afterfeathers (downy plumes attached to the main feathers). Combined, these feathers provide a complex, overlapping network of insulation – an essential feature of penguin adaptations for the harsh Antarctic climate.
Finally, penguins’ feathers have also adapted to store air – which basically serves two purposes. This air can be released when penguins are underwater to prevent drag and to allow them to be streamlined and faster when swimming. It also enables them to quickly shed water when back on land.
Penguin adaptations in their skin
Penguins’ skin is another example of how these birds have adapted to the cold Antarctic climate. Penguins have been known to carry DSG1 gene, which in humans is linked to very thick skin on feet and palms. This means that over years penguins have developed a far thicker than the other birds, allowing them to survive in freezing weather.
Additionally, like all marine animals that live in Antarctica, they have a thick layer of insulating blubber under their skin that prevents cold temperatures from their body and act as a barrier to the cold.
Penguin adaptations in their feet
You may have at some point wondered how it is that penguins’ feet, despite being in direct contact with the ice, don’t freeze. The science behind this very thing allows us to understand another important way how penguins have adapted to live their lives in the harsh weather of Antarctica.
Firstly, their bodies can control the amount of blood flow that reaches their feet by varying the diameter of arterial vessels. In cold weather, this can be reduced, in hot weather, it can be increased.
Secondly, they have ‘countercurrent heat exchangers’ at the top of their legs. The arteries that lead towards the feet contain warm blood and as the arteries break into smaller vessels, they pass closely by the venous vessels that are bringing cold blood back from the feet. This allows heat to move between the two and so stops penguin’s feet from getting lower than 1°C freezing.
Emperor penguin adaptations
Emperor penguin is the only animal that breeds in the Antarctic winter, and this species has been forced to adapt to even severe conditions than most other species of penguins. A key adaptation to such cold environment is the fact that they have only a few extremities, such as very small flippers and bills, which ultimately means that less heat is lost when blood comes into contact with cold air.
But perhaps the most important and best known of the adaptations that penguins have done is their social behavior which sees them huddling together in groups of hundreds and thousands as a way protecting them from severe cold. These huddles are typically characterized by constant movements, as those penguins which are on the outskirts of the group don’t receive the same wind protection as penguins on the inside of the group.
As a result of these huddles, emperor penguins can reduce heat loss by up to an incredible 50%.
Emperor Penguin Anatomical Adaptations
The large size of emperor penguins helps them to retain heat. Emperors are twice in size to the next biggest penguin; this makes them able to successfully survive the extreme cold temperatures in winter without having to feed for long periods. A large size coupled with low surface to area ratio enables them to slow down the loss of heat, a simple shape and flippers that can be held close to the body also reduces surface area on land.
The short stiff tail of emperor penguins helps on land which basically forms a tripod when the penguin rocks back slightly on its heels, this gives the minimum contact area with the ice or snow to prevent heat loss.
Thick fat (or blubber) layers of this species of penguins act like insulation and help in trapping the body heat inside. This is a little like wrapping yourself in a blanket, but on the inside. In some animals this is even further refined, with the animals selectively able to reduce blood flow to the blubber layers. The further the blood is from the skin surface, the less heat is lost.
Blubber layers can also be used as an energy reserve, for example male elephant seals can live off their fat reserves during summer.
Chicks have soft down for insulation, this is a more effective insulator on land than the feathers that the adult birds have, but are of little use in the sea, and they must moult and grow feathers before they can swim.