Aptenodytes forsteri

Aptenodytes forsteri

True to its name, the emperor penguin is the largest of all penguins and one of the heaviest of all birds. Scientifically speaking, Aptenodytes means 'featherless diver' and alludes to the emperor penguin's astounding ability to dive deeper than any other bird on earth. However, contrary to what this name suggests, emperor penguins do have feathers - 4 layers of them in fact to protect them from the chilling Antarctic weather. But their feathers are so peculiar looking, almost scale-like, that early observers mistook them for something else.

A. forsteri, the emperor penguin's species name, honours Johann Reinhold Forster (1729-98). Forster was a naturalist on Captain James Cook's voyage around the world and was one of the first people ever to describe penguins.

All names aside, the emperor penguin is one of the 'coolest' birds on the planet. Read on to find out more...

What do they look like?

From a distance emperor penguins look like little men wearing tuxedos. They are easily recognized by their black cap, blue-grey neck, orange ear-patches and bill, yellow breast and white belly. Emperor penguins may stand as tall as 1.15 m (3.8 ft) and can weigh as much as 40 kg (88 lbs). They are the largest of the 17 penguin species and one of the heaviest birds on earth. How does your size compare?

Emperor chicks (far left in this picture) have a thick coat of grey down feathers. On the head, the down is dark with a large white circle surrounding each eye with a white band running between them under the chin. It is thought that these head markings help parents find their chicks in the darkness of the Antarctic winter. Once they lose their down, young emperor penguins are purely black and white in colour. After one year the collar feathers turn yellow and as the penguin ages these feathers gradually change to a deeper orange.

Where do they live?

Emperor penguins live off the coast of Antarctica. Unlike all other penguins in the Antarctic, emperor penguins do not migrate to warmer climates for the winter months. In fact, they are the only penguin that is able to survive the harsh Antarctic winters and breed during some of the worst weather conditions on earth.

Emperor penguins gather in huge, crowded groups called rookeries or colonies. There are approximately 45 colonies around Antarctica, that range in size from 200 to 50,000 penguins. Colonies of emperors gather on the sea ice (ice that forms naturally on the sea) around Antarctica and use coastal ice cliffs and icebergs for shelter. Amazingly, emperors are the only birds in the world that can, and usually do, spend their whole life without ever coming on land.

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Colony of Emperor Penguins

How do they keep warm?

Against the bone chilling Antarctic weather, the penguin's first defense is its feathers, just like a mammal's is its fur. Close to the skin, emperor penguins have a thick layer of woolly down, then 4 layers of scale-like feathers packed in at 80 feathers per square inch, all covered in a greasy waterproof coating. Like seals and whales, emperor penguins also have a thick layer of fat or blubber below the skin for extra insulation.

In the Antarctic in the dead of winter, temperatures can fall more than 40 degrees below zero; freezing winds (called katabatic winds) blow off the polar plateau and blizzards can reach speeds of 200km/hr. Under these conditions, feathers and blubber just aren't good enough and the emperor penguins must depend on each other to survive. Unlike other types of penguins who are all territorial, emperor penguins don't mind sharing their space with others. To keep warm, emperors crowd together in large groups called huddles or 'tortues' (turtles - as French investigators called them). Inside a huddle the temperature can rise as much as 20 degrees above the outside air temperature. Each emperor penguin takes its turn in the warmest and coldest spots in the huddle. In a continuous circling whirlpool-like motion, the birds on the edge of the huddle move in out of the wind and cold as the birds in the centre make their way towards the outside again. How's that for co-operation!?!

Why can't penguins fly?

It is true that penguins cannot fly in the way that we think of most birds flying, that is through the air. Penguins are so heavy and their wings so small (relative to the rest of their body) that their wings simply can't support them in the air. In the water though, a penguin's wings and streamline figure are perfectly suited for high speed travel. Underwater they are in flight, using their wings for propulsion they look like birds do flying in the air. As penguins get all of their food from the ocean and spend nearly their whole lives on the water (except when they are breeding) they really have no need to fly as other birds do.

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How do they get around?

Underwater, penguins are amazingly quick travellers with swimming speeds reaching 3.5 -4 m/s. (To compare, most fur seals and sea lions swim at speeds of less than 2m/s). When they aren't diving for food, penguins break into a curious (and incredible for a bird) behaviour called 'porpoising'. Swimming underwater just below the surface they build up a good speed, then shoot forwards into the air for some distance and drop back into the water. There they build up speed once again and the whole process is repeated.

Out of the water penguins stand up straight, like funny little men, with their webbed feet sticking out from underneath large bellies. On such short little legs, a penguin's walk becomes more of a waddle. At the best of times this makes for pretty slow travelling; to cover great distances penguins flop on their bellies and toboggan instead, using their wings to push them along the ice.

What do they eat?

Emperor penguins may seem awkward on land, but there is no doubt that they are strong and agile in the water. This makes them very good predators. Near the top of the ocean food chain, emperor penguins feed on fish, squid and krill. Those that prey on the emperors include large marine mammals, and sharks in the spring time. Emperor penguins are terrific divers and can dive deeper than any other bird. Records show that emperors have plunged as deep as 535 m (~1750 ft) and can hold their breath up to 18 minutes. For the most part though, emperors spend less than 5-6 minutes at a time underwater diving down around 100m.

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How do they reproduce?

Emperor penguins have a most unique breeding cycle! The breeding season occurs through the winter months and is coordinated with the forming and the break up of sea ice. As crazy as this may seem, the breeding season is actually perfectly coordinated so that the chicks will be mature enough to leave their parents by the summer, when conditions are better and there is more food around.

Mating pairs gather on breeding colonies early in the winter just after the sea ice has formed (around March). For the males, this is the beginning of a 3-4 month ordeal during which time they will court, mate and incubate an egg without a single meal. With this in mind, the males make sure to stock up before leaving for the breeding colony. Males often arrive on the colony so full that their

Around mid-May, the female lays one egg and almost immediately passes it to the male who will be in charge of incubation. Emperor penguin parents do not build a nest; instead the male penguin holds the egg on his feet and tucks it under a fold of his feathered skin to keep it warm. For 65 wintery days the male stays to incubate the egg through harsh Antarctic winter conditions. As all the breeding males are in the same boat they huddle together, eggs on feet, for warmth and survival.

Meanwhile the females are feeding out at sea, building up reserves of food that she will later regurgitate for the new-born chick soon to come. At the beginning of September, the female returns from the ocean and finds her mate by the sound of his call. The egg is carefully passed back from the male to the female and almost immediately it begins to hatch. This egg transfer takes no more than about ten seconds. If the egg or a newly hatched chick were to fall on the ice, it would freeze to death in two minutes. Now that the egg is hatched the male can finally head out to feed and from this point on the parents take turns going out to sea and returning to feed their offspring.

As the weather improves and the chicks develop, they gather into day-care centres called crèches while the penguin parents are feeding at sea. Chicks can recognize their parents by the sound of their call; when the pairs return from the water they trumpet at each crèche until their chick runs out to meet them.

As summer nears and the weather warms, the inshore ice begins to break up and food becomes more abundant. Sometime between December and February, the chicks downy coats are replaced with normal penguin feathers and the chicks leave their parents to venture out on their own. They must learn to swim and feed themselves for they will soon head off the colony and out to sea where they will stay for several years.

How long do they live?

It is not known for sure how long emperor penguins usually survive in the wild. It is estimated however that emperor chicks that reach adulthood have a good chance of surviving 20 years or more.

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Where can I find out more?

Check out these web sites for more information and lots of cool pictures on the emperor and other penguins...

University of Michigan's Animal Diversity Pages: Emperor Penguin

National Geographic's "Creature Feature": Emperor Penguin

Australian Antarctic Division | check here too!

Antarctic Connection Emperor Penguin page

Questions and answers about sea birds

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