Emperor penguin

Name and taxonomy

George Robert Gray, an English zoologist, described the species in 1844. He built the genus name Aptenodytes from Greek parts that mean a diver without wings. The species name honours Johann Reinhold Forster, the German naturalist who sailed with James Cook on his second voyage. Forster saw a large penguin in 1773 or 1774 and recorded it as a king penguin, but it was probably an emperor.

The emperor penguin sits in the family Spheniscidae and the order Sphenisciformes, which holds every penguin. Its only living relative in the genus is the king penguin, Aptenodytes patagonicus. Wikidata lists common names in more than twenty languages, such as Kaiserpinguin in German and manchot empereur in French. The English name and the German name both call the bird an emperor, and the king penguin takes the lesser title.

Evolution and relatives

Genetic studies place Aptenodytes at the base of the penguin family tree. In other words, the line that led to the emperor and king penguins split from every other penguin early. Evidence from mitochondrial and nuclear DNA puts that split at around 40 million years ago. A third species, Ridgen's penguin, is known from fossils in New Zealand that date to about three million years ago.

Penguins as a group belong with the tube-nosed seabirds and loons in a wider bird lineage called Aequornithes. Like other penguins, the emperor probably lost flight as its ancestors became better and better divers. Solid bones, a dense coat of feathers and a thick fat layer all fit a life spent in cold water.

Appearance

An adult measures 101 to 132 centimetres from bill to tail and weighs 22 to 45 kilograms. The standing height is lower than the body length, about 81 to 97 cm, and the tallest bird measured stood 108 cm. Many reports confuse the two figures, which is why some books give a height of 1.2 metres or more. Each flipper spans 76 to 89 cm, and the sexes look alike in colour and size. Males are heavier, and a female weighs about 18 kg less than a male on average.

The head, chin, throat, back and the top of the flippers are black. The belly and the underside of the flippers are white, and the upper breast is pale yellow. A bright yellow patch sits behind each ear and fades toward the shoulder. The bill is about 8 cm long, black on top, with a pink, orange or lilac stripe along the lower half. Chicks wear silver-grey down with a black head and a white face, and young birds have white cheeks and a black bill.

Over the Antarctic summer the dark plumage fades to brown, and the yearly moult follows in January and February. The moult takes about 34 days, which is fast for a bird. New feathers grow to a third of their length under the old ones before those fall, so the bird never loses its insulation.

Habitat and range

The emperor penguin lives all the way around Antarctica, almost entirely between 66 and 77 degrees south. It breeds on firm pack ice close to the coast, sometimes as far as 18 kilometres from the shore. Colonies form where ice cliffs and icebergs block some of the wind. Only three colonies on land have ever been reported, and one of those has since vanished. Since 2009, some colonies have moved onto shelf ice in years when the sea ice formed late.

By 2022 scientists knew of 66 breeding colonies. The most northerly is on Snow Hill Island near the tip of the Antarctic Peninsula. Outside the breeding season the birds spend most of their time in the pack ice zone, where open water is close by. Winter air can fall to minus 40 degrees Celsius, and the water stays near minus 1.8 degrees.

Wanderers have turned up on Heard Island, South Georgia, the Falkland Islands and the southern tip of South America. A few reach New Zealand, and in November 2024 one bird landed on a beach in Western Australia. GBIF holds records from 18 countries, but most of those are vagrants, museum specimens or zoo birds.

Diet and feeding

The emperor penguin eats fish, krill and squid, and the mix changes from place to place. Fish matter most, and the Antarctic silverfish makes up the largest share of the diet. Other regular prey are cod icefish, two kinds of squid and Antarctic krill. An adult eats about 2 to 3 kg a day, and up to 6 kg a day before the long fast of the breeding season. A rough, barbed tongue holds slippery prey so it cannot slide back out.

The bird hunts in open water, in ice-free patches called polynyas and in cracks in the pack ice. One tactic is to dive to about 50 metres and look up for fish that swim against the underside of the ice. It swims up, takes the fish, dives again and repeats the move about six times before it surfaces to breathe. Birds that hunt together may time their dives and surfacing as a group. A record dive reached 564 metres and lasted 21.8 minutes, and another bird touched 535 metres near McMurdo Sound.

Behaviour and social life

The emperor penguin is social at every stage of its life. It breeds in colonies of up to several thousand birds and often hunts in groups. It holds no territory and defends no nest site, because it has no nest. Individuals can be active by day or by night, and the species spreads out into the ocean from January to March.

The huddle is the behaviour that lets the species survive winter. Ten to several thousand birds pack together, each leaning on a neighbour, with the young in the centre. Birds on the cold upwind edge shuffle round to the sheltered side, so the whole mass slowly churns. Every bird gets a turn inside and a turn outside. One study found that 84% of pairs stayed together during a huddle, and a typical huddle lasted about 1.6 hours.

It swims at about 6 to 9 kilometres per hour and pushes with both the up and the down stroke of the flipper. On the ice it walks with a rocking gait or lies on its belly and pushes itself along with feet and flippers. To save heat on land it rests on its heels and tail, so the soles of its feet stay off the ice. It is strong, and a crew of six men once failed to hold a single male that they wanted for a zoo.

Communication and senses

Because there is no nest to return to, an emperor penguin must find its mate and chick by voice alone. Each bird has its own call, and the species shows the widest range of individual calls of any penguin. The call uses two frequency bands at the same time, which makes it easy to tell apart in a noisy colony. A chick begs with a whistle that rises and falls, and a parent answers only its own chick.

Once a pair has formed, both birds fall silent so that other penguins do not cut in. The calls return after the egg is laid, and the female uses them to pick out her mate among hundreds of males. Posture matters too: a bird that lifts its bill and holds its flippers slightly out is asking not to be attacked. Like other diving birds, the emperor probably sees well under water, but the sources say little about its senses.

Reproduction and life cycle

Emperor penguins can breed at about three years old, but most wait one to three more years. In March and April the adults walk 50 to 120 km across the ice to the colony as the days grow short. A lone male stands still, drops his head to his chest and gives a call that lasts one or two seconds. A pair then stand face to face, stretch their necks up and hold the pose for several minutes. The species does not mate for life, and only about 15% of pairs meet again the next year.

In May or early June the female lays one egg of about 460 to 470 grams. It is pale greenish white, about 12 by 8 cm, and only 2.3% of her weight, a tiny egg for a bird this size. She passes it to the male at once, and a dropped egg freezes on the ice within a minute or two. The male rests it on his feet under a fold of bare skin and holds it there for 65 to 75 days. He is the only male penguin that incubates alone, and by hatching he has fasted for about 120 days.

A newly hatched chick weighs about 315 g and needs its parents for both food and warmth. If the mother is still away, the father feeds it a curd from a gland in his throat for up to 7 days. The female returns from mid July to early August, finds her mate by his call and takes over the chick. The parents then swap duties, one at sea and one at the colony, until the chicks gather in a creche at 45 to 50 days. Chicks moult from November and leave for the sea in December and January at about half of adult weight. Only about 19% of chicks survive their first year, but an adult has a 95.1% chance of surviving each year.

Predators and threats

The leopard seal is the main predator of adults and takes birds soon after they enter the water. Orcas also take adults at sea, and they will attack a penguin of any age near the water. Neither seal nor orca depends on emperors, and both probably prefer smaller penguins when those are plentiful. Most dives are short and shallow, which cuts the time a predator has to reach the bird. A black back and a white belly hide the swimming shape from above and from below.

On the ice the southern giant petrel is the chief killer of chicks and causes over a third of chick deaths in some colonies. The south polar skua mostly takes dead chicks and eggs, because the live chicks are too large by the time it arrives. Cold, starvation and storms kill far more chicks than any predator. The largest threat to the species is the loss and early break-up of sea ice as the climate warms.

Population and conservation

A 2009 count from satellite images put the population at about 595,000 adults in 46 colonies. Later surveys raised the number of known breeding sites to 61, and then to 66. About 35% of the known birds live north of the Antarctic Circle. Satellite images from 2009 to 2018 showed a fall of about 10%, or more than 20,000 adults.

The IUCN listed the species as Near Threatened from 2012, then raised it to Endangered in April 2026. The new listing rests on projected sea-ice loss rather than on a count that has already fallen. Chile and Argentina list it as Vulnerable, and the United States has weighed it for its Endangered Species Act. One model predicts a 45% chance that numbers will halve by 2073. A 2023 study found that more than 90% of colonies could face near extinction from breeding failure by the end of the century.

The Halley Bay colony, the second largest, lost almost every chick for three years after 2015 when the ice broke early. Some of those birds moved 55 km south to the Dawson-Lambton colony, which grew tenfold. The Dion Islands colony, studied since 1948, vanished at some point before 2009, the first known loss of a whole colony.

Relationship with humans

Antarctica had no people before the modern age, so no human culture grew up alongside this bird. Scientists study it to learn how a body copes with deep dives, low oxygen and extreme cold. Tour operators run day trips and overnight trips to see colonies, mostly in the Antarctic summer. One study found that chicks in a creche grew nervous when a helicopter came within 1,000 metres. Researchers also suspect that people carried bird diseases such as avian influenza to the continent.

Zoos have tried to keep emperors since the 1930s, and early attempts mostly failed. Aalborg Zoo in Denmark built a chilled house and kept one bird for 20 years. SeaWorld San Diego hatched the first captive chicks, and over 20 have followed there since 1980. In 2011 a young emperor came ashore in New Zealand, ate 3 kg of sand and was nursed back to health before release. The species harms no one, and no negative effect on people is known.

In culture and myth

There is no traditional folklore about the emperor penguin, because no people lived where it breeds. Its place in culture is modern and comes mostly from film. The French documentary March of the Penguins, released in 2005, followed a colony through one breeding season. Happy Feet, from 2006, made a dancing emperor chick its hero and carried a message about warming seas and overfishing. Surf's Up, from 2007, gave the species a surfing character.

More than 30 countries have printed the bird on postage stamps, including Australia, Britain, Chile and France. In popular writing the emperor stands for endurance and for devoted parents. More recently it has become a symbol of what melting sea ice will cost.