How long does a king penguin usually incubate its single egg before it hatches?

A king penguin usually incubates its single egg for about 55 days before it hatches.

King penguins have an unusual breeding cycle because they do not build nests and generally raise only one chick at a time. After laying, the female transfers the egg to the male, although both parents take turns carrying it on top of their feet beneath a loose fold of abdominal skin.

The incubation period is divided into shifts that typically last around two weeks. While one parent incubates, the other goes to sea to feed. This arrangement allows the egg to remain warm even in the cool sub-Antarctic environment where king penguins breed.

King penguins are often confused with emperor penguins, but their breeding schedules differ. Emperor penguins incubate their eggs through the Antarctic winter, while king penguins usually breed in milder island colonies. A king penguin chick may take many months to become independent after hatching.