Longest fledging period

Native to northern Antarctica and subantarctic islands, king penguins (Aptenodytes patagonicus) have the longest breeding cycle of all penguins at 13–16 months, and it can take 10–13 months for their chicks to fledge (i.e., develop their first set of waterproof feathers), which is a record among all birds. This species lays one egg, which both parents take turns to incubate. Once the egg hatches, the parents share the work of feeding the chick for about six weeks, before both heading to sea to eat for about nine months, during which time the chicks are left on their own in the rookery. Because the chicks still have their downy feathers at this stage (which aren’t waterproof), they cannot go into the ocean to hunt for food, so they must fast during much of this period, often going for as long as 3–5 months without eating. When the parents finally return, they continue to feed their offspring for another few months until their first set of waterproof feathers grows in.

Older king penguin chicks are nearly the same size as the adults, but look so different that early explorers thought they were actually two separate species of penguin.

Standing approximately 70–100 centimetres (2 feet 3 inches–3 feet 3 inches) tall, king penguins are the second-largest living species of penguin, only surpassed by the emperor penguin (Aptenodytes forsteri).