The Gentoo Penguin (Pygoscelis papua) is easily identifiable by the wide white stripe extending like a bonnet across the top of its head. Chicks have grey backs with white fronts. Adult Gentoos reach a height of 75 to 90 cm. They are considered to be the fastest underwater swimming penguins and can reach speeds of up to 36 km/h.
Two sub-species of this penguin are recognized
- Pygoscelis papua papua
- and the smaller Pygoscelis papua ellsworthii.
Males have a maximum weight of about 8 kg before moulting and a minimum weight of about 5.5 kg before mating. For females the maximum weight is 7.5 kg before moulting, but their weight drops to below 5 kg when guarding the chicks in the nest.
Gentoos breed on many sub-Antarctic islands, however the main colonies are located on the Falkland Islands, South Georgia and Kerguelen Islands. Smaller populations are found on Macquarie Island, Heard Islands, South Shetland Islands and the Antarctic Peninsula. Currently the total breeding population is estimated to be over 300,000 pairs.
Nests are usually made from a circular pile of stones and can be quite large, measuring 20 cm high and 25 cm in diameter. The stones are guarded with intense jealousy and their ownership can be the subject of noisy disputes between rival penguins. They are also highly prized by females, even to the point that a male penguin can obtain the favors of a female by offering her a particularly nice stone.
Two eggs are laid, both weighing around 130 g. The parents share the duty of incubation and the eggs hatch after 34 to 36 days. The chicks remain in the nest for about 30 days and then being to form creches. The chicks moult into sub-adult plumage and go out to sea at about 80 to 100 days.
Gentoo penguins are opportunistic feeders, and around the Falklands are known to eat fish, crustaceans (such as krill) and squid. Fish make up about 15% of their diet.
In the water, sea lions, leopard seals, and orca, are all predators of the Gentoo. On land there are no predators to the adults, but birds have been known to steal their eggs and chicks.
The Gentoo are the most timid species of penguin.
The name gentoo comes from the Portuguese language, being a corruption of the word gentio meaning “pagan” or “gentile”. During the 17th century, the name was also applied to members of the Hindu faith.