Life Cycle Of Penguins

Penguins are some of the most unusual birds on earth. These semi-aquatic, flightless hunters can thrive in nearly any climate, from the tropics to the tundra. The penguin life cycle is fascinatingly intricate, especially that of emperor penguins. These birds are one of the few animal species that can live and breed in frigid Antarctica.

Emperor penguins are the tallest and heaviest penguins in the world, with newborns weighing around 11 ounces, and usually being around a foot long. For comparison, the world's smallest penguin species, the little penguin, is around this size when fully grown. Emperor penguin chicks come into the world during the harsh Antarctic winter, the most frigid winter on earth with temperatures that can easily drop to -100 degrees Fahrenheit. Because of this, and because chicks do not develop proper down (warm, insulating feathers) until a few weeks of age, they must spend the first few weeks of their lives being warmed by their parents. Male and female emperor penguins have an insulated pouch, called a brood pouch, between their feet, just below their bellies. Chicks must stay in this pouch until their down develops, about 45 days after they hatch.

Emperor penguin chicks are born into large groups called colonies. Penguins of all species are social, and stick together in colonies, even those that live in tropical climates. Emperor penguin colonies spread out in summer, but huddle together for warmth in winter. Sometimes, chicks hatch while their mothers are away, collecting food. The chick's father may feed the chick a kind of "milk" (produced by special glands in his throat) to help the chick survive until the mother returns. Flamingos, pigeons and emperor penguins are the only birds on earth that can produce such "milk." Even other species of penguin are not capable of producing it. Once the mother returns, the father penguin carefully transfers their chick to her brood pouch (the adults touch toes and nudge the baby from one pouch to another) and then leaves himself, to find food at sea. The mother penguin feeds her chick the food she gathered during her time away, by regurgitating, or vomiting, food into the chick's mouth. Once a chick's down develops, it will leave the brood pouches of its parents and join other chicks in its colony, huddling in a group called a crèche for warmth. The chick's parents will still return, in shifts, to feed the chick during this time.

Over the course of a few months, emperor penguin chicks grow to between 3 and 4 feet tall. Their baby down falls out and is gradually replaced with adult feathers. This process is called molting. Once a penguin chick has most of its adult feathers, its parents stop feeding it. As spring arrives, the penguin parents leave for the sea. Chicks must go without food until their adult feathers completely come in, which can take up to a month, at which point they are able to trek to the sea themselves and hunt.

Like all penguin species, adult emperor penguins have sleek, waterproof feathers. This is vitally important because emperor penguins do all of their hunting in the water. All penguin species eat a diet of mostly seafood, and emperor penguins are no exception. They can eat all manner of aquatic animals, from squid to crabs to fish. Their bodies are built for hunting underwater, from their strong flippers to their webbed feet. Despite their large size, adult emperor penguins are very fast underwater, which helps them hunt quick prey such as Antarctic silverfish. It also helps them avoid predators such as leopard seals and killer whales. These predators tend to go after young penguins, who are inexperienced at maneuvering underwater. This means that new penguin adults must learn quickly, in order to survive.

Emperor penguins live in colonies all their lives, though they only huddle together when weather gets harsh. Adult emperor penguins cannot breed until they are around three years old, and usually wait around two to three years after reaching sexual maturity to begin the process of finding a mate.

Male penguins give courtship displays to females, which involve calls and bobbing head movements. If a female is impressed by his display, she will join him, signaling to the rest of the colony that they have formed a mated pair.

Female penguins lay just one egg at a time. The eggs have thick shells, to insulate them from the cold. Most birds nest either in trees or on the ground. However, emperor penguin eggs would freeze in the open air, which means that the female penguin must pass her egg to her partner's brood pouch as soon as she lays it. This process is dangerous, since the egg will die within moments if it touches the frigid ground. Once the transfer is complete, the female penguins leave together, for the sea. The males watch after the egg for most of its incubation, until the females return around two months later. During this time, males may lose up to half their body weight.

When the female returns, the egg, or in some cases, the newly hatched chick, is transferred to the mother's pouch, and the males leave to find food for themselves and their families.

From chick to breeding adult, emperor penguins have one of the most complex life cycles of any bird, due to the extreme conditions they must bear, especially during mating season. Because of their physical and behavioral adaptations, these incredible birds are able to reproduce and thrive in some of the harshest conditions on earth.