Marine Animal Encyclopedia
Emperor Penguin Aptenodytes forsteri
Reaching heights of over three feet (one meter), the largest penguin in the world is the Emperor Penguin. Their markings resemble those of the King Penguin, but this species is larger and the two species generally do not have overlapping distributions. Emperor Penguins spend all year in Antarctica, while King Penguins live in sub-antarctic island groups and in southern South America.
Emperor Penguins are foraging predators that feed on fishes, squids, and sometimes krill in the cold, productive currents around Antarctica. Scientists have demonstrated that these penguins can dive to depths of at least 1700 feet (500 m) in search of food. Though they feed in the open ocean, Emperor Penguins nest on the ice surface. This penguin is the only species that nests during the winter, and its nesting cycle is fascinating. After mating, the female lays a single, large egg that the male will incubate it until it hatches. The transfer of the egg from the female to the male can be difficult, and some couples drop it. Even if the egg survives being dropped, it will quickly freeze to death, as the penguins have little means to pick it back up. As soon as the egg is safely with the male, the female heads to the open ocean to feed. The male keeps the egg on top of his feet, covered with a blanket of feathers, skin, and fat for two months in the dead of winter. During this time, he does not feed and huddles with other nearby males to conserve body heat. Temperatures may reach -40F (-40C). Penguins, like all birds, are warm blooded, so going two months without food takes an extreme toll on the male’s body, since he must rely on his energy stores. He may lose as much as 50% of his body weight. As the egg finally hatches, the females return to care for the newly hatched chick, and the male is finally able to leave and feed. This nesting strategy – each female only laying one egg and each male only caring for one egg – leads to monogamy in this species, where males and females have only one partner. However, unlike in some other penguin species, Emperor Penguins often have different partners from year to year.
As nesting colonies only form during the winter, Emperor Penguins are hard to study. It is very difficult for people to spend the winter in Antarctica. However, scientists have developed a means to track Emperor Penguin population sizes using satellites. As these penguins are clear black dots on an otherwise white landscape, satellite pictures of their breeding ground allow scientists to account for their numbers and study their movements.
The Emperor Penguin is considered near threatened. Populations are stable, and it is not currently at risk of extinction. However, this species may be particularly vulnerable to ecosystem changes caused by climate change. Both of Earth’s poles are changing more rapidly than other latitudes, so the Emperor Penguin’s habitat might be at risk. As this species nests primarily on ice, any significant change to Antarctic ice may threaten the breeding colonies. Therefore, it is important for scientists to continue to study the Antarctic ecosystem and Emperor Penguin populations to ensure that the numbers remain stable.