The emperor penguin (Aptenodytes forsteri) is the tallest and heaviest penguin species and lives only in Antarctica. Male and female emperor penguins look similar, growing up to 100 cm (39 in) long and weighing between 22 and 45 kg (49 to 99 lb). Their head and back feathers are black, clearly separated from their white belly, pale-yellow chest, and bright-yellow ear patches.
Like all penguins, emperor penguins cannot fly. They have a body shaped for swimming, and their wings are stiff and flat, acting as flippers for moving through water. They eat mainly fish, but also crustaceans like krill and cephalopods like squid. When hunting, emperor penguins can stay underwater for about 20 minutes and dive as deep as 535 meters (1,755 feet). They have special traits that help with this, such as a unique type of blood protein that works well at low oxygen levels, solid bones that help prevent pressure-related injuries, and the ability to slow their metabolism and stop non-essential body functions.
Emperor penguins are the only penguin species that breed during Antarctica’s winter. They travel 50 to 120 kilometers (31 to 75 miles) across the ice to reach breeding colonies that may have thousands of individuals. The female lays one egg, which the male incubates for about two months while the female returns to the sea to feed. Afterward, the parents take turns hunting for food and caring for their chick. In the wild, emperor penguins usually live 20 years, though some may live as long as 50 years.
Taxonomy
Emperor penguins were first described in 1844 by English zoologist George Robert Gray. He used parts of Ancient Greek words to create the genus name, "Aptenodytes," which means "without wings diver." The species name honors Johann Reinhold Forster, a German naturalist who traveled with Captain James Cook on his second voyage. Forster officially named five other penguin species. He may have been the first person to see emperor penguins in 1773–74. He recorded a sighting of what he thought was a king penguin (A. patagonicus), but the location suggests it might have been an emperor penguin (A. forsteri).
Emperor penguins and king penguins are the only two living species in the genus Aptenodytes. Fossils of a third species, Ridgen's penguin (A. ridgeni), were found in New Zealand from the late Pliocene, about three million years ago. Studies of penguin behavior and genetics show that Aptenodytes is a basal genus, meaning it split off from the branch that led to all other living penguin species. Evidence from mitochondrial and nuclear DNA suggests this split occurred around 40 million years ago.
Description
Adult emperor penguins are 110–120 cm (43–47 in) long, with an average length of 115 cm (45 in). Scientists measure penguins from the tip of their beak to the end of their tail, which can sometimes lead to confusion between body length and standing height. Some sources report standing heights as high as 1.5 m (4 ft 11 in), but most studies focus on body length. Some older papers mention a standing height of 1.2 m (3 ft 11 in). While standing height is rarely reported in scientific studies, Prévost (1961) measured 86 wild emperor penguins and found the tallest individual to be 1.08 m (3 ft 7 in). Friedman (1945) measured 22 wild penguins and recorded heights between 83–97 cm (33–38 in). Ksepka et al. (2012) measured the standing height of 11 emperor penguin skins in the American Museum of Natural History and found heights between 81–94 cm (32–37 in). Adult emperor penguins weigh between 22.7 and 45.4 kg (50 to 100 lb), with males typically heavier than females. They are the fifth heaviest living bird species, after large ratites. Weight changes with the season, as both males and females lose weight while raising chicks and incubating eggs. During the Antarctic winter, male emperor penguins protect their eggs for over two months without eating, losing about 12 kg (26 lb) of body weight. Adult penguins weigh between 25 kg (55 lb) and 45 kg (99 lb), with weights decreasing during the breeding season. Males usually weigh 18 kg (40 lb) more than females.
Emperor penguins have streamlined bodies to swim efficiently and wings that function like stiff, flat flippers. Their tongues have backward-facing barbs to help hold prey. Males and females are similar in size and color. Adult emperor penguins have dark black feathers on their heads, chins, throats, backs, flippers, and tails. Their black feathers sharply contrast with white feathers on their wings, bellies, and upper chests. Their ear patches are bright yellow, and their bills are 8 cm (3.1 in) long, with black upper parts and pink, orange, or lilac lower parts. Juvenile emperor penguins have white ear patches, chins, and throats, with black bills. Chicks are covered in silver-gray down, with black heads and white masks. A chick with completely white feathers was seen in 2001, but it was not considered an albino because it did not have pink eyes. Chicks weigh about 315 g (11.1 oz) after hatching and fledge when they reach about 50% of an adult’s weight.
Emperor penguins’ dark feathers fade to brown from November to February (the Antarctic summer) before their yearly molt in January and February. Molting takes about 34 days, which is faster than in most other birds. New feathers grow from the skin before old feathers fall out, helping reduce heat loss. New feathers then replace the old ones as they finish growing.
The average yearly survival rate of adult emperor penguins is 95.1%, with an average life expectancy of 19.9 years. Researchers estimate that 1% of hatched emperor penguins could live to be 50 years old. However, only 19% of chicks survive their first year of life, meaning 80% of the population consists of adults five years or older.
Emperor penguins do not have fixed nesting sites, so they rely on vocal sounds to identify mates, parents, and chicks. They use a complex system of calls, which vary more between individuals than any other penguin species. These calls use two frequency bands at once. Chicks use a whistling sound to beg for food and contact parents.
Emperor penguins breed in the coldest environment of any bird species. Air temperatures can drop to −40 °C (−40 °F), and wind speeds can reach 144 km/h (89 mph). Water temperatures are as low as −1.8 °C (28.8 °F), much colder than the penguins’ average body temperature of 39 °C (102 °F). To stay warm, emperor penguins have dense feathers that provide 80–90% of their insulation and a thick layer of fat under their skin (up to 3 cm or 1.2 in) before breeding. Their feathers are very dense, with about 9 feathers per square centimeter (58 per square inch). A combination of afterfeathers and down feathers likely helps with insulation. On land, muscles help hold feathers upright, trapping air next to the skin to reduce heat loss. In water, feathers flatten to waterproof the skin and underlayer. Preening (grooming) is essential for keeping feathers oily and water-repellent.
Emperor penguins can keep their body temperature stable without changing their metabolism in a wide range of temperatures, called the thermoneutral range (−10 to 20 °C or 14 to 68 °F). Below this range, their metabolism increases significantly, but they can still maintain their core body temperature from 38.0 °C (100.4 °F) down to −47 °C (−53 °F). Swimming, walking, and shivering increase metabolism, as does the breakdown of fats by enzymes triggered by the hormone glucagon. At temperatures above 20 °C (68 °F), emperor penguins may become stressed as their body temperature and metabolism rise. They may try to cool down by breathing faster and raising their wings to expose more skin to the air.
In addition to cold, emperor penguins face high pressure during deep dives, up to 40 times the surface pressure, which could cause injury in most animals. Their bones are solid, not air-filled, preventing such injuries. While diving, emperor penguins reduce oxygen use by slowing their heart rate to as low as 15–20 beats per minute and shutting down non-essential organs. This allows longer dives. Their hemoglobin and myoglobin can carry oxygen efficiently even at low blood concentrations, helping them function with very little oxygen without losing consciousness.
Distribution and habitat
The emperor penguin lives around the Antarctic, mostly between 66° and 77° south latitude. These penguins usually breed on stable pack ice near the coast and up to 18 km (11 mi) from the shore. Breeding colonies are often found in areas with ice cliffs and icebergs that protect them from strong winds. Three land colonies have been reported: one (now gone) on a shingle spit at the Dion Islands on the Antarctic Peninsula, one on a headland at Taylor Glacier in Victoria Land, and one at Amundsen Bay. Since 2009, some colonies have been found on shelf ice instead of sea ice, especially when sea ice forms late. As of 2022, there were 66 known breeding colonies.
The northernmost breeding population is on Snow Hill Island, near the northern tip of the Peninsula. Individual penguins have been seen on Heard Island, South Georgia, and occasionally in New Zealand. The furthest north a penguin has been recorded was in Denmark, Western Australia, in November 2024. This penguin, believed to have come from eastern Antarctica, was found by surfers and taken to conservationists for evaluation.
In 2009, the total population of emperor penguins was estimated to be about 595,000 adult birds, spread across 46 known colonies in the Antarctic and sub-Antarctic. Around 35% of the population lives north of the Antarctic Circle. Major breeding colonies were at Cape Washington, Coulman Island in Victoria Land, Halley Bay, Cape Colbeck, and Dibble Glacier. Colonies sometimes change over time, with groups splitting off and moving away from the main colony. Some colonies have disappeared entirely. The Cape Crozier colony on the Ross Sea shrank greatly between the Discovery Expedition in 1902–03 and the Terra Nova Expedition in 1910–11, dropping to a few hundred birds. It may have nearly gone extinct due to changes in ice shelf position. By the 1960s, it had recovered, but by 2009, it had again dropped to about 300 birds.
In April 2026, the International Union for Conservation of Nature (IUCN) declared emperor penguins and Antarctic fur seals as endangered species. The main reason for their decline is the loss of sea ice caused by climate change from greenhouse gas emissions. Satellite images from 2009 to 2018 showed a loss of about 10% of the emperor penguin population, over 20,000 adult birds. Based on this data, scientists estimate there is a 45% chance the population could drop by more than 50% by 2073.
After reviewing threats, scientists concluded that human-caused climate change is the biggest risk to emperor penguins. Early sea-ice break-up in spring is already affecting colonies, and future changes will continue to impact their breeding, feeding, and moulting habitats.
The species was previously listed as near threatened by the IUCN and as least concern before 2012. It is now being considered for the US Endangered Species Act along with nine other penguin species. The main reasons for increased risk include less food due to climate change and fishing, disease, habitat loss, and human disturbance at breeding sites. Tourism is a concern, as one study found that emperor penguin chicks become more nervous when helicopters approach within 1,000 m (3,300 ft).
Population declines of 50% in Terre Adélie were seen due to higher adult deaths, especially males, during a warm period in the late 1970s, which reduced sea-ice coverage. Egg hatching success also dropped when sea-ice increased, and chick deaths rose. Emperor penguins are highly sensitive to climate changes. In 2009, the Dion Islands colony, studied since 1948, was reported to have disappeared over the previous decade, with the birds’ fate unknown. This was the first confirmed loss of an entire colony. From September 2015, strong El Niño events, winds, and record-low sea ice caused almost total breeding failure in the Halley Bay colony, killing thousands of chicks for three years. Meanwhile, penguins moved to the Dawson-Lambton colony 55 km (34 mi) south, where the population increased tenfold between 2016 and 2018. However, this increase was smaller than the number of penguins lost from Halley Bay.
In January 2009, a study by the Woods Hole Oceanographic Institution predicted that global climate change could push emperor penguins to the brink of extinction by 2100. The study used a model to predict how sea-ice loss would affect a large colony at Terre Adélie. It forecasted an 87% population drop, from 3,000 breeding pairs in 2009 to 400 by 2100.
Another study in 2014 by the same institution again warned that emperor penguins face risks from global warming, which melts sea ice. This study predicted all colonies would decline by 2100 due to habitat loss. Loss of ice reduces krill, a key food source for emperor penguins. A 2023 study found that climate change could cause more than 90% of emperor penguin colonies to face near-extinction from breeding failures as rising temperatures lead to sea-ice loss.
Behaviour
The emperor penguin is a social animal that lives in groups during nesting and hunting. Birds that hunt together may work together when diving and coming up to the surface. These penguins are active both during the day and night. A grown emperor penguin spends most of the year traveling between its nesting area and the ocean where it hunts for food. The species spreads out into the ocean from January to March.
In 1971, the American scientist Gerry Kooyman changed how scientists study penguin hunting habits by attaching automatic devices to emperor penguins to record their dives. He found that the species can dive as deep as 265 meters (869 feet) and stay underwater for up to 18 minutes. Later research showed a female penguin dove to 535 meters (1,755 feet) near McMurdo Sound. Scientists believe emperor penguins may be able to dive even deeper and stay underwater longer, as the accuracy of the recording devices decreases at great depths. Studies of one penguin’s diving behavior showed it regularly dove to 150 meters (490 feet) in water that was 900 meters (3,000 feet) deep. It also made shallow dives of less than 50 meters (160 feet) and deeper dives of more than 400 meters (1,300 feet) in water that was 450 to 500 meters (1,480 to 1,640 feet) deep. This suggests the penguins may be hunting near the ocean floor. In 1994, a penguin from Auster rookery dove to 564 meters (1,850 feet), and the dive lasted 21.8 minutes.
Both male and female emperor penguins hunt for food up to 500 kilometers (310 miles) from their nesting areas to feed their chicks. During each trip, a penguin may travel 82 to 1,454 kilometers (51 to 903 miles). After a male penguin finishes incubating an egg, it goes directly to areas of open water called polynyas, which are about 100 kilometers (62 miles) from the colony.
The emperor penguin swims efficiently by using both upward and downward strokes. The upward stroke helps the penguin stay at a certain depth. Its average swimming speed is 6 to 9 kilometers per hour (3.7 to 5.6 miles per hour). On land, it walks with a wobbling gait or slides over ice on its belly, using its feet and wing-like flippers to move. Like all penguins, it cannot fly. Emperor penguins are very strong. In one instance, six men tried to catch a male penguin for a zoo, but the penguin pushed them around until they all had to work together to catch it. The penguin weighed about half as much as a human.
To stay warm, emperor penguins huddle together in a tight group called a huddle or turtle formation. These groups can include 10 to several hundred birds, with each penguin leaning on the one next to it. The center of the group is the warmest, so young penguins are usually there. Penguins on the outside of the group slowly move to the leeward side, creating a slow turning motion that allows each penguin to take turns being on the inside and outside.
Emperor penguins face dangers from birds and sea animals. Southern giant petrels are the main predators of baby penguins, causing more than one-third of chick deaths in some colonies. They also eat dead penguins. South polar skuas mainly eat dead chicks, as live chicks are too large for them to attack. Sometimes, a parent penguin may try to protect its chick, but it may not fight if the chick is sick or weak.
The only known predators that attack healthy adult emperor penguins in the ocean are leopard seals, which hunt adult and young penguins soon after they enter the water. Orcas, or killer whales, mostly hunt adult penguins at sea but may attack penguins of any age near water.
Although emperor penguins can begin breeding at about three years old, they usually start breeding one to three years later. The breeding cycle begins in March and April, when adult penguins travel to nesting areas, often walking 50 to 120 kilometers (31 to 75 miles) inland from the edge of the pack ice. The start of this journey seems to be triggered by shorter days. Scientists have used artificial lighting to mimic Antarctic day lengths and successfully encourage breeding in penguins held in captivity. Researchers used satellite images to find new emperor penguin nesting areas in Antarctica, increasing the estimated population by 5 to 10 percent to about 278,000 breeding pairs. Because these areas are remote and have harsh weather, scientists find penguin populations by looking at aerial images and identifying large areas of ice stained with penguin guano. These discoveries added 11 new nesting sites to the total of 50 previously known sites.
In March or April, when temperatures can drop to −40 °C (−40 °F), emperor penguins begin courtship. A male penguin stands still, places its head on its chest, and makes a short call before moving around the colony and repeating the call. A male and female then face each other, with one extending its head and neck and the other copying the movement. They hold this posture for several minutes. Once paired, the couple walks together, with the female usually following the male. Before mating, one penguin bows deeply to its partner, pointing its beak close to the ground, and the other does the same.
Contrary to popular belief, emperor penguins do not stay with the same mate for life. They are serially monogamous, meaning they have one mate each year but may choose a different mate the next year. Fidelity between years is about 15 percent. The short time available for mating seems to influence this, as penguins prioritize finding a mate and breeding over waiting for a previous partner to return.
In May or early June, the female penguin lays one egg that weighs 460 to 470 grams (16 to 17 ounces). The egg is pear-shaped, pale greenish-white, and measures about 12 centimeters by 8 centimeters (4.7 inches by 3.1 inches). It is only 2.3 percent of the mother’s body weight, making it one of the smallest eggs relative to the mother’s size in any bird species. About 15.7 percent of the egg’s weight is shell, which is thick to reduce the risk of breaking.
After laying the egg, the mother uses up all her food reserves. She carefully gives the egg to the male and returns to the sea for two months to feed. Transferring the egg can be difficult, especially for first-time parents, and many couples drop or crack the egg. If the egg breaks, the chick inside dies quickly because the egg cannot survive the cold for more than one to two minutes. If a couple loses an egg, they end their relationship and return to the sea, coming back to the colony the next year to try again. After a successful transfer, the female leaves, and the male incubates the egg on his feet for about 65 to 75 days. The emperor penguin is the only penguin species where the male alone incubates; in all other penguin species, both parents take turns. By the time the egg hatches, the male has fasted for about
Relationship with humans
Since the 1930s, people have tried to keep emperor penguins in captivity. Malcolm Davis of the National Zoological Park was among the first to attempt this. He captured penguins from Antarctica and successfully moved them to the National Zoological Park on March 5, 1940. These penguins lived there for up to six years.
Before the 1960s, most efforts to keep penguins in captivity failed. At that time, people had limited knowledge about caring for penguins and learned mostly through trial and error. Aalborg Zoo was the first to achieve some success. They built a cooled building for the penguins. One penguin lived there for 20 years, and a chick was born, though it died shortly after.
Today, emperor penguins are kept in only a few zoos and aquariums in North America and Asia. The first successful breeding of emperor penguins in captivity happened at SeaWorld San Diego, where more than 20 penguins have been born since 1980. In 1999, 55 emperor penguins were counted in North American zoos and aquariums. In China, the first successful breeding occurred at Nanjing Underwater World in 2009, followed by Laohutan Ocean Park in Dalian in 2010. Since then, emperor penguins have been kept and bred at other facilities in China. In 2017, the only confirmed set of twin emperor penguins (a rare event, as the species usually lays only one egg) hatched at Sun Asia Ocean World in Dalian. In Japan, emperor penguins are housed at the Port of Nagoya Public Aquarium and Wakayama Adventure World, with successful hatching at Adventure World.
In June 2011, a young emperor penguin was found on a beach near Wellington, New Zealand. The penguin had eaten 3 kg (6.6 lb) of sand, which it mistook for snow, along with sticks and stones. It required several surgeries to remove these items to save its life. After recovering, the penguin was named "Happy Feet" (after the 2006 movie) and fitted with a tracking device. It was released into the Southern Ocean 80 km (50 mi) north of Campbell Island on September 4. Scientists lost contact with the penguin eight days later, likely because the tracking device fell off or the penguin was eaten by a predator.
Emperor penguins are known for their unique life cycle in extreme environments. Their story has been shared in books and films. The French documentary La Marche de l'empereur (also called March of the Penguins in English) was widely shown in movie theaters in 2005. It described the penguins' reproductive cycle. The animated movie Happy Feet (2006) and its sequel Happy Feet Two (2011) feature emperor penguins as main characters. The films show their life cycle and highlight environmental issues like global warming and overfishing. The animated movie Surf's Up (2007) includes a surfing emperor penguin named Zeke "Big-Z" Topanga. Emperor penguins have also appeared on stamps in more than 30 countries, including Australia, Great Britain, Chile, and France. One stamp from 1962 showed an emperor penguin as part of an Antarctic expedition series.