Emperor penguins raise chicks through the Antarctic winter with no nest to find
Emperor penguins breed in the harshest conditions any bird faces: air down to minus 40 degrees Celsius and winds up to 144 kilometres per hour. With no fixed nest to return to, mates and chicks find each other purely by voice, among colonies that can number several thousand.
The emperor is the tallest and heaviest living penguin, found only in Antarctica. Adults stand about a metre tall and weigh 22 to 45 kilograms, with males and females alike in size and plumage. George Robert Gray described the species in 1844, building its genus name Aptenodytes from Greek for wingless diver; the species name honours Johann Reinhold Forster, the naturalist on Captain James Cook's second voyage. Its only living relative in the genus is the king penguin, while fossils of a third species from about three million years ago turned up in New Zealand.
Uniquely among penguins, emperors breed in winter. They walk 50 to 120 kilometres over the ice to colonies, usually on stable sea ice sheltered by ice cliffs and icebergs. The female lays a single egg and heads back to sea, while the male incubates it for just over two months. Because nobody has a fixed site, they rely on a complex set of calls with the widest individual variation of any bird to recognise partners and offspring.
Their bodies are built for extremes. They can hold their core temperature steady without speeding up metabolism across a range from minus 10 to 20 degrees, compared with a body temperature around 39 degrees and seawater at minus 1.8. On deep dives, where pressure can reach 40 times that at the surface, solid bones prevent barotrauma, the heart slows to 15 to 20 beats a minute, and non-essential organs shut down. Dives can last around 20 minutes. Barbs on the tongue point backwards to stop prey escaping, and the annual moult takes only about 34 days.
Adults survive well, at 95.1 percent a year and an average life expectancy of 19.9 years, but only 19 percent of chicks make it through their first year. Stragglers wander far: one reached Denmark, Western Australia, in November 2024, the most northerly record.
Source: Emperor penguin
