Fauna of the Antarctic

The Adélie penguin is one of five penguin species which breed in the Antarctic. Click to enlarge
The Adélie penguin is one of five penguin species which breed in the Antarctic.
Source: Fritz Hertel/UBA

What the polar bear is to the Arctic, the penguin is to the Antarctic. Of the 18 penguin species there are in the world, five of them breed only in the Antarctic. The region has more to offer than the sight of these charming flightless birds. Although there is not such a large of number of species at the southern end of the world, many kinds of animals have adapted to the harsh living conditions.

Table of Contents

 

Krill as the basis for the food chain

The number of higher animal species present in the Antarctic is relatively small. Their habitat is limited to the narrow, ice-free coastal areas and the ocean, on which they depend for their food. The most important link in the food chain of the Southern Ocean is Antarctic krill (Euphausia superba), a shrimp-like crustacean measuring four to six cm in length. It feeds mainly on planktonic diatoms and zooplankton. With an estimated total incidence of one billion tonnes in the Antarctic, krill is the basic food resource for many living creatures such as squid, bony fish, penguins and sea birds, seals and whales.

Some 208 species of fish live in the coastal region and under the shelf ice of Antarctica. 96 species (46 percent) are Antarctic fish (Notothenioidei), a suborder of perch-like fish (Perciformes) which is particularly well adapted to live at very low temperatures. Snailfish (Liparidae) and eelpouts (Zoarcidae) make up 31 percent and 11 percent of the other fish fauna, respectively. Most of these are benthic fish species living on the seafloor.

 

Little mascot in a tailcoat

The most widely recognised animal in the Antarctic is probably the penguin. This flightless diving bird lives exclusively in the southern hemisphere, but only five of all eighteen known species are residents of the Antarctic who are endemic as breeders on the continent, the adjacent ice or neighbouring islands. The most well known species is the emperor penguin (Aptenodytes forsteri), the largest diving bird on Earth and the only permanent inhabitant of the Antarctic. The other four penguin species of the Antarctic and the sub-Antarctic islands are the chinstrap penguin (Pygoscelis antarctica), the gentoo penguin  (Pygoscelis papua), the macaroni penguin (Eudyptes chrysolophus), and the Adélie penguin (Pygoscelis adeliae). Because of the cold ocean current, the other penguin species live on sub-Antarctic islands, along the west coast of South America, on the southern coast of Africa, in New Zealand and Australia, as well as on the Galapagos Islands.

In addition to penguins, there are about 26 species of sea birds in the Antarctic, including albatrosses, the southern giant petrel and Cape petrel, skuas, terns, sheathbills, and the snow and Antarctic petrels, which can even be found inland.

Only very small lower animals are permanent colonisers of Antarctica's ice-free land areas: tardigrades, mites or springtails (Collembola, a primitive group of insects). A special characteristic of the Antarctic Peninsula is the existence of the flightless Belgica antarctica midge, whose twelve-millimetre length makes it the largest endemic terrestrial animal.

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Only very few mammals – but very large ones

The two groups of marine mammals – seals and whales – are the only mammals present in the Antarctic. There are six species of seals: the crabeater seal (Lobodon carcinophagus), the southern elephant seal (Mirounga leonina), the Weddell seal (Leptonychotes weddelli), the Ross seal (Ommatophoca rossii), the fur seal (Arctocephalus spec.), and the leopard seal (Hydrurga leptonyx). The number of seals is far greater in the Antarctic than in the Arctic. The total world population of the Antarctic crabeater seal, for example, is estimated to be between eleven and twelve million.

This vast population of seals, as with many other species, thrives mainly due to the huge stocks of Antarctic krill.

Of the 80 whale species in the world, 14 are endemic in the Antarctic and are often present in the Antarctic summer. They include six baleen whales: the blue whale, the largest mammal on Earth; the fin whale, the world's second largest mammal; the sei whale; the humpback whale; and the Antarctic minke and common whales, in addition to seven toothed whales such as the killer whale, the sperm whale or bottlenose whales. Whale and seal hunting at the beginning of the 20th century decimated their populations. While some species have bounced back rather well (for example the crabeater seal, which now have populations of several million individuals), the populations of other species such as the blue whale are still far from ideal and still classified as endangered.

The present increase in tourism in the Antarctic is a new source of threat to native animals and their natural habitat. Approaching people can raise the stress levels of animal mothers and disrupt milk production or feeding, which can be life-threatening for their young. The mere presence of a human can cause an animal to feel disturbed, frightened or threatened. This is why one should observe animals at a safe distance so as not to displace them from their natural environment. Read more about the rules of conduct and behaviour and details on the distances to be kept in the Visitor Guidelines for the Antarctic.

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