Penguins live in the freezing climate of the Antarctic.
At least that’s what most people believe, whether they are getting their information from biology textbooks or the animated movie “Happy Feet.” However, the image of penguins living ONLY in icy climates isn’t actually 100% true. In fact, one species of penguin- the Galapagos Penguin- actually lives near the equator, off the coast of Peru. Additional species in Australia, New Zealand and South Africa also have never set foot on the Antarctic continent. That said, it IS true that penguins are mostly cold climate birds.
Penguins live, survive and thrive in such cold temperatures because they have adapted to their icy environment in a variety of ingenious ways.
Penguins evolved in parts of the world where land life and vegetation is extremely limited. The Antarctic region, especially, can best be descibed as an “ice desert.” In order to survive, nature adapted penguins for life in the sea, which offers the most ready food source in icy conditions. Some penguin species will spend as much as 70-75% of their life in water.
Although penguins are definitely BIRDS, they are quite unlike the flying birds we see in our back yards. Where flying birds have hollow bones to make them more lightweight for flight, penguins have heavy solid bones that provide “ballast” for extensive dives after fish- their primary source of food. Penguins are remarkable divers, being able to reach depths of more than 1500 feet while staying submerged for up to 20 minutes. And while they may seem clumsy and slow on land, they are truly “built for speed” under water. Their bodies are virtually “torpedo shaped” and their flipper-like wings can propel them at speeds over 20 miles an hour- the Gentoo Penguin is generally recognized as the fastest swimmer.
But HOW does a penguin survive, in water that’s mostly near freezing, and in air temperatures that drop below minus 50 degrees? Part of the secret lies in an insulating layer of subcutaneous blubber (a type of fat) that protects it. This fatty layer allows the penguin to maintain its body temperature in water down to just below 26 degrees fahrenheit- the temperature at which sea water freezes.
On top of the fatty layers, Penguins have an extremely dense coat of interlocking and overlapping feathers. Where the blubber offers the best protection in water, the feathers are the first line of defense against freezing air. In extreme cold, penguins can puff up their feathers to create an insulating layer of air between their skin and the ambient atmosphere. They also spend a lot of time preening, much of which revolves around coating their feathers with oil from a gland near their tail. This makes their feathers all but water impermeable, explaining how they can stay in water for so long and still not get wet.
Penguins are also adapted for cold by their body shape. Consider a penguin’s “physique.” It’s basically a cylinder that’s pointed at each end. This means that it’s body surface area is the smallest it can possibly be, for an animal its size- as a result of which heat loss is kept to an absolute minimum.
The penguin’s biggest source of body heat loss is its feet, which also is generally the only part of its anatomy actually touching the ice or frozen rocks. Penguins are able to partly counter heat loss through their feet by lowering the bottom of their bodies enough that a fold of fat and feathers cover their feet, and some species additionally rock backwards so only their heels touch the ground, and they are actually balanced on a “tripod” of their heels and their stiff tail feathers (which have no blood circulation, and thus no heat loss).
Penguins’ social structure also serves to help them survive extreme cold. Many species will “huddle” together in groups of 1000s of birds, which allows them to conserve as much as 40-50% more body heat than an individual bird could. In addition, they will always turn their dark backs towards the sun, getting the most of any extra heat the dark color absorbs.
Thus the penguin has adapted to survive quite handily, despite frigid waters, freezing temperatures and 125 mile-an-hour winds.
