Emperor penguin  (Aptenodytes forsteri)

The emperor penguin is classified as Least Concern (LC) on the IUCN Red List (1).

Standing over a metre in height and weighing up to 40 kilograms, the emperor penguin (Aptenodytes forsteri) is the undisputed heavyweight of the penguin world (2) (4) (5). Slow and dignified, the emperor penguin is a stunning bird with a blue-grey back that shades into a black tail, and a characteristically white belly flushed with yellow (2) (4) (6). Deep yellow ear patches on either side of the head fade down the neck and the upper chest, while the remainder of the head and throat is black (2) (6).

In order to limit heat loss, the emperor penguin’s extremities are reduced in size, with a small head and bill relative to body size, and flippers that are proportionately 25 percent smaller than those of other penguins (2). A highly developed counter-current circulatory system also provides an efficient mechanism for retaining heat within the body. Furthermore, the scale-like feathers of the emperor penguin are tightly packed in multiple layers that only the harshest winds can ruffle, while the feet are strongly clawed for gripping the ice (2) (6) (7).

Emperor penguin chicks are mostly silvery grey, with a blackish head and a conspicuous white mask around the eyes, cheek and throat (3).

The emperor penguin has a circumpolar distribution (3), and being a true Antarctic bird is rarely seen in sub-Antarctic waters (4). There are around 40 known breeding colonies, all of which occur on the pack ice surrounding the Antarctic continent, the Antarctic Peninsula and nearby islands (2) (3) (6).

The breeding colonies of the emperor penguin are mainly found on level areas of stable sea-ice. These may be close to the coast or up to 18 kilometres offshore, and are often sheltered sites in the lee of ice-cliffs, hills or bergs (3).

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).

Owing to the apparent stability of its large and wide-ranging population, the emperor penguin is not currently considered to be threatened (8). Sadly, however, climate change models predict a colossal reduction in the extent of the Antarctic sea-ice, which would result in the loss of large areas of emperor penguin breeding habitat. Based on climate change models, recent research indicates this species could decline by as much as 95 percent by 2100 (9). Another study also suggests that increasing eco-tourism and consequential disturbance could also be having a negative effect on the emperor penguin (10).

In the face of climate change, the emperor penguin will likely have to adapt, migrate, or change the timing of its breeding season in order to survive. Unfortunately, such a long-lived species is unlikely to be able to adapt fast enough (9).

Recommendations have been made to reduce the level of disturbance by eco-tourists by encouraging people to walk in small, tight knit groups and to stop moving whenever close to travelling emperor penguins (10).

View information on this species at the UNEP World Conservation Monitoring Centre.

To find out more about the emperor penguin, as well as other Antarctic penguins, visit:

• British Antarctic Survey:
  http://www.antarctica.ac.uk/
• BBC Wildlife Finder:
  http://www.bbc.co.uk/nature/species/Emperor_Penguin

To find out more about the projected impact of climate change on the emperor penguin, see:

• Jenouvier, S., Caswell, H., Barbraud, C., Holland, M., Stroeve, J. and Weimerskirch, H. (2009) Demographic models and IPCC climate projections predict the decline of emperor penguin population. Proceedings of the National Academy of Sciences of the United States of America, 106: 1844-1847.

For more information on this and other bird species, see:

• BirdLife International:
  http://www.birdlife.org/