The Gentoo penguin (Pygoscelis papua) is a penguin species (or possibly a species complex) in the genus Pygoscelis. It is most closely related to the Adélie penguin and the Chinstrap penguin. Gentoo penguins are the fastest underwater swimmers of all penguins, reaching speeds up to 36 km/h (22 mph). They are well adapted to extremely cold and harsh climates.
The Gentoo penguin is easily recognized by the wide, white stripe extending like a bonnet across the top of its head and its bright orange-red bill. It has pale whitish-pink, webbed feet, and a fairly long tail - the most prominent tail of all penguin species. Chicks have grey backs with white fronts. As the Gentoo penguin waddles along on land, its tail sticks out behind, sweeping from side to side, hence the scientific name Pygoscelis, which means "rump-tailed".
Gentoo penguins are found along the coastlines of the Antarctic Peninsula, sub-Antarctic islands, and the Falkland Islands in the southern part of the Atlantic Ocean. They breed on many subantarctic islands. The main colonies are on the Falkland Islands, South Georgia, the South Sandwich Islands, and the Kerguelen Islands; smaller colonies are found on: Macquarie Island, Heard Islands, Crozet Islands, South Shetland Islands, and the Antarctic Peninsula. Gentoos breed on ice-free surfaces. Colonies can be located directly on the shoreline or considerably inland. They prefer shallow coastal areas and often nest between tufts of grass.
Gentoo penguins are diurnal and social birds, breeding in colonies and remaining together for the rest of the year. They typically live and breed in the same areas. Gentoos are very shy and do not tend to defend their territories. When encountering a predator, they will simply retreat. However, they become extremely territorial, when it comes to their nests. Every year, these birds undergo molting, which usually takes place right after fledge and departure of the chicks, lasting 25 days. During the molt, they fast and don’t go to forage at the sea. For this reason, before molting, during January, adult individuals travel to the sea to forage, staying there for about 55 days.
Gentoos are carnivorous (piscivorous) birds. Their usual diet consists of fish, cephalopods as well as crustaceans such as krill or shrimp.
Generally, Gentoo penguins are seasonally monogamous, though some pairs may remain together throughout their life. They congregate into large breeding colonies of up to 2.000 pairs at a breeding site. As the breeding season begins, the pair constructs a nest. The penguins usually build their nests at a distance of about 1 meter from each other. The female lays 2 eggs from June to the end of November. Both the male and the female participate in the incubation process, taking turns. Incubation lasts about 34-36 days, after which the chicks hatch out, staying in the nest for the following 30 days, until they form creches. At about 80-100 days old, the young undergo their first molt, gaining the sub-adult plumage, after which they go out to the sea. Typically, they first breed at 3-4 years of age, though they can occasionally breed earlier - at 2 years old.
Primary threats to this species include pollution and association with fisheries. On the other hand, human disturbance in the form of scientific studies is among other threats. Thus, penguin colonies on Kerguelen Island and Possession Island have been threatened by scientific bases around the area.
According to IUCN Red List, the total population size of the Gentoo penguin is 774,000 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List, and its numbers today are stable.