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Emperor penguin (view source)

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The '''emperor penguin''' (''Aptenodytes forsteri'') is the tallest and heaviest of all living penguin species and is endemic to [[Antarctica]]. The male and female are similar in plumage and size, reaching 122 cm (48 in) in height and weighing from 22 to 45 kg (49 to 99 lb). The dorsal side and head are black and sharply delineated from the white belly, pale-yellow breast and bright-yellow ear patches. Like all penguins it is flightless, with a streamlined body, and wings stiffened and flattened into flippers for a marine habitat.
[[File:Emperor Penguins-Snow Hill Island.jpg|thumb|right|Adult and juvenile emperor penguins ]]
The '''emperor penguin''' (''Aptenodytes forsteri'') is the tallest and heaviest of all living [[penguin]] species and is endemic to [[Antarctica]]. The male and female are similar in plumage and size, reaching 122 cm (48 in) in height and weighing from 22 to 45 kg (49 to 99 lb). The dorsal side and head are black and sharply delineated from the white belly, pale-yellow breast and bright-yellow ear patches. Like all penguins it is flightless, with a streamlined body, and wings stiffened and flattened into flippers for a marine habitat.


Its diet consists primarily of fish, but can also include crustaceans, such as [[krill]], and cephalopods, such as squid. In hunting, the species can remain submerged up to 18 minutes, diving to a depth of 535 m (1,755 ft). It has several adaptations to facilitate this, including an unusually structured haemoglobin to allow it to function at low oxygen levels, solid bones to reduce barotrauma, and the ability to reduce its metabolism and shut down non-essential organ functions.
Its diet consists primarily of fish, but can also include crustaceans, such as [[krill]], and cephalopods, such as squid. In hunting, the species can remain submerged up to 18 minutes, diving to a depth of 535 m (1,755 ft). It has several adaptations to facilitate this, including an unusually structured haemoglobin to allow it to function at low oxygen levels, solid bones to reduce barotrauma, and the ability to reduce its metabolism and shut down non-essential organ functions.
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==Description==
==Description==
Adult emperor penguins stand up to 110–130 cm (43–51 in) tall. The weight ranges from 22.7 to 45.4 kg (50 to 100 lb) and varies by sex, with males weighing more than females. It is the fifth heaviest living bird species, after only the larger varieties of ratite. The weight also varies by season, as both male and female penguins lose substantial mass while raising hatchlings and incubating their egg. A male emperor penguin must withstand the Antarctic cold for more than two months to protect his egg from extreme cold. During this entire time he does not eat anything. Most male penguins will lose about 12 kg (26 lb) while they wait for their chicks to hatch. The mean weight of males at the start of the breeding season is 38 kg (84 lb) and that of females is 29.5 kg (65 lb). After the breeding season this drops to 23 kg (51 lb) for both sexes.
Adult emperor penguins stand up to 110–130 cm (43–51 in) tall. The weight ranges from 22.7 to 45.4 kg (50 to 100 lb) and varies by sex, with males weighing more than females. It is the fifth heaviest living bird species, after only the larger varieties of ratite. The weight also varies by season, as both male and female penguins lose substantial mass while raising hatchlings and incubating their egg. A male emperor penguin must withstand the Antarctic cold for more than two months to protect his egg from extreme cold. During this entire time he does not eat anything. Most male penguins will lose about 12 kg (26 lb) while they wait for their chicks to hatch. The mean weight of males at the start of the breeding season is 38 kg (84 lb) and that of females is 29.5 kg (65 lb). After the breeding season this drops to 23 kg (51 lb) for both sexes.
 
[[File:Kaiserpinguine mit Jungen.jpg|thumb|500px|right|Colony of emperor penguins]]
Like all penguin species, emperor penguins have streamlined bodies to minimize drag while swimming, and wings that are more like stiff, flat flippers. The tongue is equipped with rear-facing barbs to prevent prey from escaping when caught. Males and females are similar in size and coloration. The adult has deep black dorsal feathers, covering the head, chin, throat, back, dorsal part of the flippers, and tail. The black plumage is sharply delineated from the light-colored plumage elsewhere. The underparts of the wings and belly are white, becoming pale yellow in the upper breast, while the ear patches are bright yellow. The upper mandible of the 8 cm (3 in) long bill is black, and the lower mandible can be pink, orange or lilac. In juveniles, the auricular patches, chin and throat are white, while its bill is black. Emperor penguin chicks are typically covered with silver-grey down and have black heads and white masks. A chick with all-white plumage was found in 2001, but was not considered to be an albino as it did not have pink eyes. Chicks weigh around 315 g (11 oz) after hatching, and fledge when they reach about 50% of adult weight.  
Like all penguin species, emperor penguins have streamlined bodies to minimize drag while swimming, and wings that are more like stiff, flat flippers. The tongue is equipped with rear-facing barbs to prevent prey from escaping when caught. Males and females are similar in size and coloration. The adult has deep black dorsal feathers, covering the head, chin, throat, back, dorsal part of the flippers, and tail. The black plumage is sharply delineated from the light-colored plumage elsewhere. The underparts of the wings and belly are white, becoming pale yellow in the upper breast, while the ear patches are bright yellow. The upper mandible of the 8 cm (3 in) long bill is black, and the lower mandible can be pink, orange or lilac. In juveniles, the auricular patches, chin and throat are white, while its bill is black. Emperor penguin chicks are typically covered with silver-grey down and have black heads and white masks. A chick with all-white plumage was found in 2001, but was not considered to be an albino as it did not have pink eyes. Chicks weigh around 315 g (11 oz) after hatching, and fledge when they reach about 50% of adult weight.  


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==Distribution and habitat==
==Distribution and habitat==
[[File:Empereur ranges.png|thumb|right|Emperor penguin range. Breeding areas in green]]
[[File:Empereur ranges.png|thumb|right|Emperor penguin range. Breeding areas in green]]
The emperor penguin has a circumpolar distribution in the [[Antarctica|Antarctic]] almost exclusively between the 66° and 77° south latitudes. It almost always breeds on stable [[pack ice]] near the coast and up to 18 km (11 mi) offshore. Breeding colonies are usually located in areas where ice cliffs and [[icebergs]] shelter them from the wind. Three land colonies have been reported: one (now disappeared) on a shingle spit at the Dion Islands on the [[Antarctic Peninsula]], one on a headland at Taylor Glacier in Victoria Land, and most recently one at Amundsen Bay. Since 2009, a number of colonies have been reported on [[ice-shelf|shelf ice]] rather than sea ice, in some cases moving to the shelf in years when sea ice forms late.
The emperor penguin has a circumpolar distribution in the [[Antarctica|Antarctic]] almost exclusively between the 66° and 77° south latitudes. It almost always breeds on stable [[pack ice]] near the coast and up to 18 km (11 mi) offshore.  Although they are known to hunt and swim around Westarctica, there are currently no known breeding colonies within the nation's borders. Breeding colonies are usually located in areas where ice cliffs and [[iceberg]]s shelter them from the wind. Three land colonies have been reported: one (now disappeared) on a shingle spit at the Dion Islands on the [[Antarctic Peninsula]], one on a headland at Taylor Glacier in Victoria Land, and most recently one at Amundsen Bay. Since 2009, a number of colonies have been reported on [[ice-shelf|shelf ice]] rather than sea ice, in some cases moving to the shelf in years when sea ice forms late.


The northernmost breeding population is on Snow Island, near the northern tip of the Peninsula.
The northernmost breeding population is on Snow Island, near the northern tip of the [[Antarctic Peninsula]].


The total population was estimated in 2009 to be at around 595,000 adult birds, in 46 known colonies spread around the Antarctic and sub-Antarctic; around 35% of the known population lives north of the [[Antarctic Circle]]. Colonies are known to fluctuate over time, often breaking into "suburbs" which move apart from the parent group, and some have been known to disappear entirely. The Cape Crozier colony on the Ross Sea dropped drastically in size between the first visits by the Discovery Expedition in 1902–03 and the later visits by the Terra Nova Expedition in 1910–11; it was reduced to a few hundred birds, and may have come close to extinction due to changes in the position of the ice shelf. By the 1960s it had rebounded dramatically, but by 2009 was again reduced to a small population of around 300.
The total population was estimated in 2009 to be at around 595,000 adult birds, in 46 known colonies spread around the Antarctic and sub-Antarctic; around 35% of the known population lives north of the [[Antarctic Circle]]. Colonies are known to fluctuate over time, often breaking into "suburbs" which move apart from the parent group, and some have been known to disappear entirely. The Cape Crozier colony on the Ross Sea dropped drastically in size between the first visits by the Discovery Expedition in 1902–03 and the later visits by the [[Terra Nova Expedition]] in 1910–11; it was reduced to a few hundred birds, and may have come close to extinction due to changes in the position of the ice shelf. By the 1960s it had rebounded dramatically, but by 2009 was again reduced to a small population of around 300.


===Conservation status===
===Conservation status===
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==Behavior==
==Behavior==
[[File:PENGUIN LIFECYCLE H.jpg|thumb|450px|left|Lifecycle of the Emperor Penguin]]
The emperor penguin is a social animal in its nesting and its foraging behavior; birds hunting together may coordinate their diving and surfacing. Individuals may be active day or night. A mature adult travels throughout most of the year between the nesting area and ocean foraging areas; the species disperses into the oceans from January to March.
The emperor penguin is a social animal in its nesting and its foraging behavior; birds hunting together may coordinate their diving and surfacing. Individuals may be active day or night. A mature adult travels throughout most of the year between the nesting area and ocean foraging areas; the species disperses into the oceans from January to March.


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===Predators===
===Predators===
The emperor penguin's predators include birds and aquatic mammals. [[Southern giant petrels]] are the predominant land predator of chicks, responsible for up to 34% of chick deaths in some colonies though they often scavenge dead penguins as well. The [[south polar skua]] mainly scavenges for dead chicks, as the live chicks are too large to be attacked by the time of its annual arrival in the colony. Occasionally, a parent may defend their chick from attack, although it may be more passive if the chick is sickly.
The emperor penguin's predators include birds and aquatic mammals. [[Southern giant petrel]]s are the predominant land predator of chicks, responsible for up to 34% of chick deaths in some colonies though they often scavenge dead penguins as well. The [[south polar skua]] mainly scavenges for dead chicks, as the live chicks are too large to be attacked by the time of its annual arrival in the colony. Occasionally, a parent may defend their chick from attack, although it may be more passive if the chick is sickly.


The only known predators thought to attack healthy adults, and who attack emperor penguins in the water, are both mammals. The first is the [[leopard seal]]), which takes some adult birds, as well as fledglings soon after they enter the water. [[Orca|Orcas]], mostly take adult birds, although they will attack penguins of any age in or near water.
The only known predators thought to attack healthy adults, and who attack emperor penguins in the water, are both mammals. The first is the [[leopard seal]]), which takes some adult birds, as well as fledglings soon after they enter the water. [[Orca|Orcas]], mostly take adult birds, although they will attack penguins of any age in or near water.


===Courtship and breeding===
===Courtship and breeding===
[[File:EmperorPenguinFeedingChick.jpg|thumb|right|500px|Emperor penguin feeding chick]]
Emperor penguins are able to breed at around three years of age, and usually commence breeding around one to three years later. The yearly reproductive cycle begins at the start of the Antarctic winter, in March and April, when all mature emperor penguins travel to colonial nesting areas, often walking 50 to 120 km (31 to 75 mi) inland from the edge of the [[pack ice]]. The start of travel appears to be triggered by decreasing day lengths; emperor penguins in captivity have been induced successfully into breeding by using lighting systems mimicking seasonal Antarctic day lengths.
Emperor penguins are able to breed at around three years of age, and usually commence breeding around one to three years later. The yearly reproductive cycle begins at the start of the Antarctic winter, in March and April, when all mature emperor penguins travel to colonial nesting areas, often walking 50 to 120 km (31 to 75 mi) inland from the edge of the [[pack ice]]. The start of travel appears to be triggered by decreasing day lengths; emperor penguins in captivity have been induced successfully into breeding by using lighting systems mimicking seasonal Antarctic day lengths.


The penguins start courtship in March or April, when the temperature can be as low as −40 °C (−40 °F). A lone male gives an ecstatic display, where it stands still and places its head on its chest before inhaling and giving a courtship call for 1–2 seconds; it then moves around the colony and repeats the call. A male and female then stand face to face, with one extending its head and neck up and the other mirroring it; they both hold this posture for several minutes. Once in pairs, couples waddle around the colony together, with the female usually following the male. Before copulation, one bird bows deeply to its mate, its bill pointed close to the ground, and its mate then does the same.
The penguins start courtship in March or April, when the temperature can be as low as −40 °C (−40 °F). A lone male gives an ecstatic display, where it stands still and places its head on its chest before inhaling and giving a courtship call for 1–2 seconds; it then moves around the colony and repeats the call. A male and female then stand face to face, with one extending its head and neck up and the other mirroring it; they both hold this posture for several minutes. Once in pairs, couples waddle around the colony together, with the female usually following the male. Before copulation, one bird bows deeply to its mate, its bill pointed close to the ground, and its mate then does the same.


Emperor penguins are serially monogamous. They have only one mate each year, and stay faithful to that mate. However, fidelity between years is only about 15%. The narrow window of opportunity available for mating appears to be an influence, as there is a priority to mate and breed which often precludes waiting for the appearance of the previous year's partner.
The female penguin lays one egg in May or early June. After laying, the mother's nutritional reserves are exhausted and she very carefully transfers the egg to the male, before immediately returning to the sea for two months to feed. The transfer of the egg can be awkward and difficult, and many couples drop the egg in the process. When this happens, the chick inside is quickly lost, as the egg cannot withstand the freezing temperatures on the icy ground. The male spends the dark winter incubating the egg in his brood pouch, balancing it on the tops of his feet, for 64 consecutive days until hatching. The emperor penguin is the only species where this behavior is observed; in all other penguin species both parents take shifts incubating.


The female penguin lays one 460–470 g (1.01–1.04 lb) egg in May or early June; it is vaguely pear-shaped, pale greenish-white, and measures around 12 cm × 8 cm (4 3⁄4 in × 3 1⁄4 in). It represents just 2.3% of its mother's body weight, making it one of the smallest eggs relative to the maternal weight in any bird species. 15.7% of the weight of an emperor penguin egg is shell; like those of other penguin species, the shell is relatively thick, which minimizes risk of breakage.
By the time the egg hatches, the male will have fasted for around 115 days since arriving at the colony. To survive the cold and winds of up to 200 km/h (120 mph), the males huddle together, taking turns in the middle of the huddle. They have also been observed with their backs to the wind to conserve body heat. The female penguin returns at any time from hatching to ten days afterwards, from mid-July to early August. She finds her mate among the hundreds of fathers by his vocal call and takes over caring for the chick, feeding it by regurgitating the food that she has stored in her stomach.


After laying, the mother's nutritional reserves are exhausted and she very carefully transfers the egg to the male, before immediately returning to the sea for two months to feed.[64] The transfer of the egg can be awkward and difficult, and many couples drop the egg in the process. When this happens, the chick inside is quickly lost, as the egg cannot withstand the freezing temperatures on the icy ground. The male spends the dark winter incubating the egg in his brood pouch, balancing it on the tops of his feet, for 64 consecutive days until hatching.[66] The emperor penguin is the only species where this behavior is observed; in all other penguin species both parents take shifts incubating. By the time the egg hatches, the male will have fasted for around 115 days since arriving at the colony.[66] To survive the cold and winds of up to 200 km/h (120 mph), the males huddle together, taking turns in the middle of the huddle. They have also been observed with their backs to the wind to conserve body heat. In the four months of travel, courtship, and incubation, the male may lose as much as 20 kg (44 lb), from a total mass of 38 to 18 kg (84 to 40 lb).
The male then leaves to take his turn at sea, spending around 24 days there before returning. The parents then take turns, one brooding while the other forages at sea. If the incubating parent is not relieved by its partner before its own energy reserves are depleted, then it returns to the sea to re-feed, abandoning its doomed egg or chick at the colony site. Abandoned chicks do not survive.


Hatching may take as long as two or three days to complete, as the shell of the egg is thick. Newly hatched chicks are semi-altricial, covered with only a thin layer of down and entirely dependent on their parents for food and warmth. If the chick hatches before the mother's return, the father feeds it a curd-like substance composed of 59% protein and 28% lipid, which is produced by a gland in his esophagus. This ability to produce "milk" in birds is only found in pigeons, flamingos and male Emperor penguins. The young chick is brooded in what is called the guard phase, spending time balanced on its parent's feet and sheltered in the brood pouch.
===Feeding===
 
The emperor penguin's diet consists mainly of fish, crustaceans and cephalopods, although its composition varies from population to population. Fish are usually the most important food source, and the [[Antarctic silverfish]] makes up the bulk of the bird's diet. Other prey commonly recorded include other fish of the family Nototheniidae, the [[glacial squid]], and the hooked squid species ''Kondakovia longimana'', as well as [[Antarctic krill]]. The emperor penguin searches for prey in the open water of the [[Southern Ocean]], in either ice-free areas of open water or tidal cracks in [[pack ice]]. One of its feeding strategies is to dive to around 50 m (160 ft), where it can easily spot sympagic fish like the [[bald notothen]] swimming against the bottom surface of the sea-ice; it swims up to the bottom of the ice and catches the fish. It then dives again and repeats the sequence about half a dozen times before surfacing to breathe.
The female penguin returns at any time from hatching to ten days afterwards, from mid-July to early August. She finds her mate among the hundreds of fathers by his vocal call and takes over caring for the chick, feeding it by regurgitating the food that she has stored in her stomach. The male then leaves to take his turn at sea, spending around 24 days there before returning. The parents then take turns, one brooding while the other forages at sea. If the incubating parent is not relieved by its partner before its own energy reserves are depleted, then it returns to the sea to re-feed, abandoning its doomed egg or chick at the colony site. Abandoned chicks do not survive.


About 45–50 days after hatching, the chicks form a crèche, huddling together for warmth and protection. During this time, both parents forage at sea and return periodically to feed their chicks. A crèche may comprise up to several thousand birds densely packed together and is essential for surviving the low Antarctic temperatures.
==National Symbol of Westarctica==
As the [[National Symbols of Westarctica|national symbol]] of [[Westarctica]], the emperor penguin has been used in many ways as a representation of Westarctica's solitary dominance over the icy realm of western [[Antarctica]]. It appears on many of the nation's [[Stamps of Westarctica|stamps]] and [[Coins of Westarctica|coins]] as well as on the [[Crown Jewels of Westarctica|Seal of the Grand Duke]]


From early November, chicks begin moulting into juvenile plumage, which takes up to two months and is often not completed by the time they leave the colony; adults cease feeding them during this time. All birds make the considerably shorter trek to the sea in December or January and spend the rest of the summer feeding there.


===Feeding===
The emperor penguin's diet consists mainly of fish, crustaceans and cephalopods, although its composition varies from population to population. Fish are usually the most important food source, and the [[Antarctic silverfish]] makes up the bulk of the bird's diet. Other prey commonly recorded include other fish of the family Nototheniidae, the [[glacial squid]], and the hooked squid species ''Kondakovia longimana'', as well as [[Antarctic krill]]. The emperor penguin searches for prey in the open water of the [[Southern Ocean]], in either ice-free areas of open water or tidal cracks in [[pack ice]]. One of its feeding strategies is to dive to around 50 m (160 ft), where it can easily spot sympagic fish like the [[bald notothen]] swimming against the bottom surface of the sea-ice; it swims up to the bottom of the ice and catches the fish. It then dives again and repeats the sequence about half a dozen times before surfacing to breathe.


[[Category:Penguins]]
[[Category:Penguins]]
[[Category:Animals of Westarctica]]
[[Category:Animals of Westarctica]]
[[Category:Symbols of Westarctica]]
[[Category:Symbols of Westarctica]]
[[Category:Featured Articles]]
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