There are many different species of penguins, some more similar than others. Three closely related species are pictured above… Adelie, Chinstrap, and Gentoo (pictured in that order, left to
right). The graph shows how the populations of these penguins have changed since 1975. Adélie penguins live in tightly-packed breeding colonies that number in the thousands, giving birth to chicks during the Southern Hemisphere summer, usually in December. Gentoo penguins live in large, gregarious breeding colonies along the coastline. They build nests on beaches and in grass tussocks and are highly aggressive in defending their turf. Chinstrap penguins live for about 20 years and breed in large colonies, even at times living on icebergs floating in the open ocean. They are also an aggressive species, often getting into fights with other penguins.