In order for the chicks to fledge in the late summer season, the emperor penguin must reproduce during the Antarctic’s harsh winter, when temperatures drop as low as minus 60 degrees Celsius and wind speeds reach up to 200 kilometres per hour (2) (4). Adults make the long journey (up to 120 kilometres) across the pack ice to the breeding colonies at the onset of winter, between March and April (3) (6).
Owing to the extremeness of the environment, the emperor penguin has little time to spend on courtship, and breeding pairs form relatively quickly. Potential mates stand face-to-face, raise their heads, and stretch tall into a static posture for several minutes, before relaxing again (2). If satisfied, the pair stays together for the next six weeks until the female lays a single egg, which is immediately transferred to the male’s feet where it is kept warm under a pouch of feathery skin. The female then departs for the sea to feed, and doesn’t return until spring, whilst the male remains to incubate the egg in constant darkness (2) (3) (4) (5) (7). In order to survive, the males cast aggression aside and huddle tightly together, with up to 5,000 penguins forming one huddle in large colonies (2) (4) (5).
Hatching of the emperor penguin chick coincides, around nine weeks later, with the return of the female, whereupon the male relinquishes feeding duties (2) (4) (5) (6). Free to head for the sea to feed for the first time in around four months, the male, which will have lost around half its bodyweight, must now undertake an arduous journey of up to 100 kilometres across the ice to reach open water (2) (6) (7). Once the male returns several weeks later, both adults take it in turns to provide the chick with regurgitated meals (2). At around one to two months old, the chick joins a group of other chicks known as a crèche, allowing both adults to forage at the same time (2) (3). Then, when the sea-ice begins to break up at the height of summer, the chicks and the adults all make the journey to the sea to forage (4) (6).
The emperor penguin feeds mainly on fish, squid and krill, which it hunts in the open sea or in gaps in the sea-ice (2) (3). Like other penguins, it is an expert swimmer, typically spending two and a half to nine minutes underwater whilst diving to depths of more than 400 metres (2) (5).