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Penguins – An Overview
 Penguins are flightless sea birds of the Southern Hemisphere. In all, there are 18 species of penguins, found in South Australia, New Zealand, and off the coasts of Peru, Chile, and South Africa. Some species live as far north as the equatorial Galapagos Islands, but they are primarily cold-weather birds. There are seven species of Antarctic penguins: the Adelie, Gentoo, Macaroni, Chinstrap, Rockhopper, King, and Emperor. The Adelie and the Emperor are the two true Antarctic species.
The Oceans features three penguin species. Click on the names for more information about the penguins at the Indianapolis Zoo:
King penguins
Gentoo penguins
Rockhopper penguins
Penguins have a heavier skeleton than most birds, waterproof feathers, and specialized glands that extract and excrete excess salt. Their feathers, which even cover their bills and feet, combine with a thick layer of fat to insulate them. This works so effectively that the birds frequently overheat in the frigid waters. They vary, by species, from the sixteen inch, two and a half pound Little Blue penguin of Australia to the truly Antarctic sixty-six pound Emperor penguin, which stands more than three and a half feet tall. (The Emperor has actually been recorded at up to ninety pounds.)
Penguins swim like other birds fly. Their wings have not disappeared, nor have they become vestigial, useless appendages. Instead, they've evolved into flippers. Penguins use highly developed muscles to flap their wings to move forward, and they guide themselves with their tail. They are the only bird to "porpoise." That is to say, they launch themselves out of the water, momentarily flying in fluid arches as they continue to swim forward at high speeds like dolphins. Penguins do this in order to breathe, but porpoising also creates air bubbles that reduce friction during swimming. Gentoo penguins are thought to be the fastest of all swimming birds, achieving speeds of thirteen to seventeen miles per hour.
Penguins breed in colonies and can be fiercely territorial. They breed closely together mostly because there is very little ice-free space. But they are also highly social animals that recognize individuals and return as adults to the rookery where they were born. The colony helps these birds guard, protect, and defend their young. Within these colonies, penguins build rookeries with pebbles and guano. (The Emperor does not build any nest at all because it breeds on the ice.)
Penguins fall prey to leopard seals, sea lions, and killer whales. Skua gulls are the greatest natural threat to chicks and eggs. In their turn, penguins dive to hunt fish, squid and krill -- a small shrimp-like crustacean. Krill is a very large part of the diet. (In fact, the penguins’ dependence on krill was demonstrated in dramatic fashion in 1995, when thousands of Adelie and Emperor chicks died due to unusual movements of krill swarms.) Most penguins submerge for about one minute, but Emperors can dive as deep as 180 feet for up to 18 minutes.
The Macaroni and Rockhopper penguins are in the same genus, Eudyptes. Both have yellow crests decorating and distinguishing their heads. In fact, the Macaroni gets its name for this feature after "Macaroni Dandies," resplendently dressed 18th Century Englishmen. Some Macaronis breed on the Antarctic Peninsula. The five and a half pound Rockhopper is the smallest Antarctic species, but it compensates for its smallness by being the most aggressive of all penguins.
 The Gentoo, Chinstraps, and Adelies are the southernmost representatives of the genus Pygoscelis. These three species are roughly the same size. The Gentoo is the rarest of the three, with a population of about 350,000 to be found largely on South Georgia, an island northeast of the peninsula. The Chinstrap gets its name from markings on its head and neck, and it is considerably more abundant, at about ten million. Some Chinstrap penguins breed on the Antarctic Peninsula. The Adelie is the most numerous of the Antarctic penguins; it is also the species with the classic penguin look, being white and black with no adornments. On average, an Adelie weighs about 11 pounds and stands a little less than thirty inches tall. Along with the Emperor, the Adelie breeds widely on the continent proper. Its colonies sometimes number in the millions.
Photo by Scott Olmstead
The remaining two, the Emperor and the King of the genus Aptenodytes, look more alike than different. However, the Emperor is considerably larger, weighing twice as much on average. They both have yellow and orange markings around the neck (although the King's are brighter and tend more toward orange), black heads, white bellies, and blue-gray backs. The King breeds on the sub Antarctic islands, while the Emperor breeds on the continent's ice. Oddly, it is the only bird that will live off land its entire life.
Six of the seven Antarctic species breed during the summer; the Emperor breeds during the unbelievably cold, dark Antarctic winter. This is because the Emperor has a longer gestation period than other penguins, so it must time its cycle in order to ensure its chicks become independent during the summer abundance of food. The adults sacrifice greatly to do this, however. Both the males and females must incubate the egg continually on their feet, fasting up to three months during the winter.
Today, penguins are economically important in South America and South Africa for their guano, used for fertilizer, and as tourist attractions. In the past, commercial egg collecting caused severe damage to rookeries. Around the turn of the century, penguins were also slaughtered for their blubber -- especially the king. However, present day Antarctic penguins find their greatest human threats from inadvertent interference.
Since nearly all of Antarctica is covered in ice, competition for breeding space among penguins alone is difficult enough. However, the introduction of tourism and airstrips on the continent can affect penguins in unpredictable and dangerous ways. Unfortunate incidents, like the building of the French airstrip Dumont d'Urville on the rocky Adelie coastline, have ruined some of the best bird breeding areas on the continent. (In 1994, a tidal wave washed away a good deal of that airstrip.)
Two recent studies demonstrate that penguins have been infected with diseases most likely spread by carelessly discarded poultry. Australian scientists operating out of Mawson station detected antibodies for infections bursal disease virus (IBDV) in Emperor chicks and adult Adelies, and Swedish scientists found Salmonella in penguins on Bird Island.
Under the Antarctic Treaty System, the Agreed Measures for the Conservation of Antarctic Fauna and Flora (Recommendations III-8 of 1964) prohibit killing, wounding, capturing, or molesting any native mammal or bird in Antarctica without a permit. The Agreed Measures are included in and strengthened by the Protocol on Environmental Protection for the Antarctic Treaty. Annex II to the Protocol prohibits the import of live poultry, and requires specific treatment for dressed poultry and its disposal.
Source: Antarctic and Southern Ocean Coalition
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