The Adélie Penguin, Pygoscelis adeliae, is a species of
penguinPenguins are a group of aquatic, flightless birds living almost exclusively in the southern hemisphere, especially in Antarctica. Highly adapted for life in the water, penguins have countershaded dark and white plumage, and their wings have become flippers...
common along the entire
AntarcticThe Antarctic is the region around the Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica and the ice shelves, waters and island territories in the Southern Ocean situated south of the Antarctic Convergence...
coast. They are among the most southerly distributed of all
seabirdSeabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s, as are the
Emperor PenguinThe Emperor Penguin 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 in height and weighing anywhere from . The dorsal side and head are black and sharply delineated from the white belly,...
, the
South Polar SkuaThe South Polar Skua, Stercorarius maccormicki, is a large seabird in the skua family Stercorariidae. An older name for the bird is MacCormick’s Skua, after explorer and naval surgeon Robert McCormick, who first collected the type specimen...
, the Wilson's Storm Petrel, the
Snow PetrelThe Snow Petrel is the only member of the genus Pagodroma. It is one of only three birds that breed exclusively in Antarctica and has been seen at the South Pole. It has the most southerly breeding distribution of any bird.-Taxonomy:...
, and the
Antarctic PetrelThe Antarctic Petrel is a boldly marked dark brown and white petrel, found in Antarctica, most commonly in the Ross and Weddell seas. They eat Antarctic krill, fish, and small squid...
. In 1840, French explorer
Jules Dumont d'UrvilleJules Sébastien César Dumont d'Urville was a French explorer, naval officer and rear admiral, who explored the south and western Pacific, Australia, New Zealand and Antarctica.-Childhood:Dumont was born at Condé-sur-Noireau...
named them for his wife, Adéle.
Taxonomy
The Adélie Penguin is one of three species in the genus
PygoscelisThe genus Pygoscelis contains three living species of penguins collectively known as "The Brush-Tailed Penguins". Their appearance - black above, white below - is the stereotypical image of penguins, and so what most people think of when they think of penguins.-Taxonomy:Mitochondrial and nuclear...
.
MitochondrialIn cell biology, a mitochondrion is a membrane-enclosed organelle found in most eukaryotic cells. These organelles range from 0.5 to 1.0 micrometers in diameter...
and
nuclearIn cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...
DNADeoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
evidence suggests the
genusIn biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
split from other penguins around 38 million years ago, about 2 million years after the ancestors of the genus
AptenodytesThe genus Aptenodytes contains two extant species of penguins collectively known as "the great penguins".-Taxonomy:...
. In turn, the Adélie penguins split off from the other members of the genus around 19 million years ago.
Distribution and habitat
There are 38 colonies of Adélie penguins, and there are over 5 million Adélies in the
Ross SeaThe Ross Sea is a deep bay of the Southern Ocean in Antarctica between Victoria Land and Marie Byrd Land.-Description:The Ross Sea was discovered by James Ross in 1841. In the west of the Ross Sea is Ross Island with the Mt. Erebus volcano, in the east Roosevelt Island. The southern part is covered...
region.
Ross IslandRoss Island is an island formed by four volcanoes in the Ross Sea near the continent of Antarctica, off the coast of Victoria Land in McMurdo Sound.-Geography:...
supports a
colonyA bird colony is a large congregation of individuals of one or more species of bird that nest or roost in close proximity at a particular location. Many kinds of birds are known to congregate in groups of varying size; a congregation of nesting birds is called a breeding colony...
of approximately half a million Adélies. The Adélie penguins breed from October to February on shores around the Antarctic continent. Adelies build rough nests of stones. Two
eggBird eggs are laid by females and incubated for a time that varies according to the species; a single young hatches from each egg. Average clutch sizes range from one to about 17...
s are laid, these are incubated for 32 to 34 days by the parents taking turns (shifts typically last for 12 days). The chicks remain in the nest for 22 days before joining creches. The chicks
moultIn biology, moulting or molting , also known as sloughing, shedding, or for some species, ecdysis, is the manner in which an animal routinely casts off a part of its body , either at specific times of year, or at specific points in its life cycle.Moulting can involve the epidermis , pelage...
into their juvenile
plumagePlumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
and go out to sea after 50 to 60 days.
Adelie penguins live in groups called colonies.
Description
These penguins are mid-sized, being 46 to 75 cm (18.1 to 29.5 in) in length and 3.6 to 6 kg (7.9 to 13.2 lb) in weight. Distinctive marks are the white ring surrounding the eye and the feathers at the base of the bill. These long feathers hide most of the red bill. The tail is a little longer than other penguins' tails. The appearance looks somewhat like a
tuxedoA tuxedo is a type of semi-formal dress for men.Tuxedo may also refer to:-Places:Canada* Tuxedo, Winnipeg, Manitoba, a city neighborhood** Tuxedo , a provincial electoral district in Manitoba...
. They are a little smaller than other penguin species. Their appearance is closest to the stereotypical image of penguins as mostly black with a white belly.
Adelie penguins can swim up to 45 miles per hour.
Adelie penguins are preyed on by
leopard sealThe leopard seal , also referred to as the sea leopard, is the second largest species of seal in the Antarctic...
s and
skuaThe skuas are a group of seabirds with about seven species forming the family Stercorariidae and the genus Stercorarius. The three smaller skuas are called jaegers in North America....
.
Behavior
Like all penguins, the Adélie is highly social, foraging and nesting in groups. They are also very aggressive to other penguins that steal stones from their nest.
Specifics of their behaviour were documented extensively by
Apsley Cherry-GarrardApsley George Benet Cherry-Garrard was an English explorer of Antarctica. He was a survivor of the Terra Nova Expedition and is acclaimed for his historical account of this expedition, The Worst Journey in the World....
(a survivor of
Robert Falcon ScottCaptain Robert Falcon Scott, CVO was a Royal Navy officer and explorer who led two expeditions to the Antarctic regions: the Discovery Expedition, 1901–04, and the ill-fated Terra Nova Expedition, 1910–13...
’s fateful final journey to the South Pole) in his book
The Worst Journey in the WorldThe Worst Journey in the World is a memoir of the 1910–1913 British Antarctic Expedition led by Robert Falcon Scott. It was written and published in 1922 by a survivor of the expedition, Apsley Cherry-Garrard, and has earned wide praise for its frank treatment of the difficulties of the expedition,...
. Cherry-Garrard noted; “They are extraordinarily like children, these little people of the Antarctic world, either like children or like old men, full of their own importance." Certain displays of their selfishness were commented upon by Levick during his surveying of penguins in the Antarctic, "At the place where they most often went in [the water], a long terrace of ice about six feet in height ran for some hundreds of yards along the edge of the water, and here, just as on the sea-ice, crowds would stand near the brink. When they had succeeded in pushing one of their number over, all would crane their necks over the edge, and when they saw the pioneer safe in the water, the rest followed.”
It was observed how the penguin's intrigue could also put them in harms way, which Scott found a particular nuisance, “The great trouble with [the dog teams] has been due to the fatuous conduct of the penguins. Groups of these have been constantly leaping on to our [ice] floe. From the moment of landing on their feet their whole attitude expressed devouring curiosity and a pig-headed disgregard for their own safety. They waddle forward, poking their heads to and fro in their usually absurd way, in spite of a string of howling dogs straining to get at them. “Hulloa!” they seem to say, “here’s a game – what do all you ridiculous things want?” And they come a few steps nearer. The dogs make a rush as far as their harness or leashes allow. The penguins are not daunted in the least, but their ruffs go up and they squawk with semblance of anger.” Regularly this attitude lead to the demise of an Adélie penguin, "Then the final fatal steps forward are taken and they come within reach. There is a spring, a squawk, a horrid red patch on the snow, and the incident is closed.” Others on the mission to the South Pole were more receptive of this element of the Adélie's intrigue. Cherry-Garrard; “Meares and Dimitri exercised the dog-teams out upon the larger floes when we were held up for any length of time. One day a team was tethered by the side of the ship, and a penguin sighted them and hurried from afar off. The dogs became frantic with excitement as he neared them: he supposed it was a greeting, and the louder they barked and the more they strained at their ropes, the faster he bustled to meet them. He was extremely angry with a man who went and saved him from a very sudden end, clinging to his trousers with his beak, and furiously beating his shins with his flippers.” This was an occurrence of some regularity, “It was not an uncommon sight to see a little Adélie penguin standing within a few inches of the nose of a dog which was almost frantic with desire and passion.”
Due to their obstinate personality traits Cherry-Garrard held the birds in great regard, “Whatever [an Adélie] penguin does has individuality, and he lays bare his whole life for all to see. He cannot fly away. And because he is quaint in all that he does, but still more because he is fighting against bigger odds than any other bird, and fighting always with the most gallant pluck.”
Diet
The Adélie penguin is known to feed mainly on
Antarctic krillAntarctic krill, Euphausia superba, is a species of krill found in the Antarctic waters of the Southern Ocean. It is a shrimp-like crustacean that lives in large schools, called swarms, sometimes reaching densities of 10,000–30,000 individual animals per cubic metre...
, ice krill,
Antarctic silverfishThe Antarctic Silverfish, Pleuragramma antarcticum is a member of the suborder Notothenioidei of the Perciform fishes.Pleuragramma antarcticum is a keystone species in the ecosystem of the Southern Ocean....
, and
Glacial SquidThe Glacial Squid is the only known species in the monotypic genus Psychroteuthis, in the family Psychroteuthidae. While only one species has been confirmed, it is possible that two undescribed species also exist. The species occurs in coastal waters near Antarctica and South America. It grows to...
(diet varies depending on geographic location) during the chick-rearing season. The
stable isotopeStable isotopes are chemical isotopes that may or may not be radioactive, but if radioactive, have half-lives too long to be measured.Only 90 nuclides from the first 40 elements are energetically stable to any kind of decay save proton decay, in theory...
record of fossil
eggshellAn eggshell is the outer covering of a hard-shelled egg and of some forms of eggs with soft outer coats.- Insect eggs :Insects and other arthropods lay a variety of styles and shapes of eggs. Some have gelatinous or skin-like coverings, others have hard eggshells. Softer shells are mostly protein....
accumulated in colonies over the last 38,000 years reveals a sudden change from a fish-based diet to krill that started two hundred years ago. This is most likely due to the decline of the
Antarctic Fur SealThe Antarctic fur seal is one of eight seals in the genus Arctocephalus, and one of nine fur seals in the subfamily Arctocephalinae. As its name suggests, the Antarctic fur seal is distributed in Antarctic waters. Around 95% of the world population breeds at the Island of South Georgia...
since the late 18th century and
Baleen whaleThe Baleen whales, also called whalebone whales or great whales, form the Mysticeti, one of two suborders of the Cetacea . Baleen whales are characterized by having baleen plates for filtering food from water, rather than having teeth. This distinguishes them from the other suborder of cetaceans,...
s in the 20th century. The reduction of competition from these predators has resulted in a surplus of krill, which the penguins now exploit as an easier source of food.
Reproduction
Adélie penguins arrive at their breeding grounds in October or November, at the end of winter and the start of spring. Their nests consist of stones piled together. In December, the warmest month in Antarctica (about -2°C), the parents take turns incubating the egg; one goes to feed and the other stays to warm the egg. The parent who is incubating does not eat. In March, the adults and their young return to the sea. The Adélie penguin lives on sea ice but needs the ice-free land to breed. With a reduction in sea ice and a scarcity of food, populations of the Adélie penguin have dropped by 65% over the past 25 years.
Migration
Adélie penguins living in the
Ross SeaThe Ross Sea is a deep bay of the Southern Ocean in Antarctica between Victoria Land and Marie Byrd Land.-Description:The Ross Sea was discovered by James Ross in 1841. In the west of the Ross Sea is Ross Island with the Mt. Erebus volcano, in the east Roosevelt Island. The southern part is covered...
region migrate an average of about 13,000 kilometers during the year as they follow the sun from their breeding colonies to winter foraging grounds and back again. The longest treks have been recorded at 17,600 kilometers.
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