page_title: Emperor penguin
section_title: Courtship and breeding
hierarchical_section_title: Emperor penguin / Behaviour / Courtship and breeding
caption_attribution_description: Deutsch&#x3a;&#32; Ei von Kaiserpinguin. Jacques Perrin de Brichambaut.English&#x3a;&#32; Egg of Emperor Penguin. Collection of Jacques Perrin de Brichambaut.Français&#x202f;&#x3a;&#32; Œuf de Manchot empereur. Collection de Jacques Perrin de Brichambaut.
context_page_description: The emperor penguin is the tallest and heaviest of all living penguin species and is endemic to Antarctica. The male and female are similar in plumage and size, reaching 100 cm in length and weighing from 22 to 45 kg. Feathers of the head and back are black and sharply delineated from the white belly, pale-yellow breast and bright-yellow ear patches. Like all penguins it is flightless, with a streamlined body, and wings stiffened and flattened into flippers for a marine habitat. Its diet consists primarily of fish, but also includes crustaceans, such as krill, and cephalopods, such as squid. While hunting, the species can remain submerged around 20 minutes, diving to a depth of 535 m. It has several adaptations to facilitate this, including an unusually structured haemoglobin to allow it to function at low oxygen levels, solid bones to reduce barotrauma, and the ability to reduce its metabolism and shut down non-essential organ functions.
  The only penguin species that breeds during the Antarctic winter, emperor penguins trek 50–120 km over the ice to breeding colonies which can contain up to several thousand individuals.
context_section_description: Although Emperor penguins can breed at around three years of age, they generally don't begin breeding for another one to three years. The yearly reproductive cycle begins at the start of the Antarctic winter, in March and April, when all mature emperor penguins travel to colonial nesting areas, often walking 50 to 120 km (31 to 75 mi) inland from the edge of the pack ice. The start of travel appears to be triggered by decreasing day lengths; emperor penguins in captivity have been induced successfully into breeding by using artificial lighting systems mimicking seasonal Antarctic day lengths. The British Antarctic Survey (BAS) used satellite imagery to find new Emperor penguin breeding sites in Antarctica, a discovery that will increase the estimated population of the Emperor penguins by 5 to 10 percent to 278,000 breeding pairs. Given their remote location and miserable conditions, penguin populations are found by scanning aerial imagery and locating enormous pages of ice that have been stained with their guano. The new discoveries bring the number of known breeding sites increased from 50 to 61.
  The penguins start courtship in March or April, when the temperature can be as low as −40 °C (−40 °F). A lone male gives an ecstatic display, where it stands still and places its head on its chest before inhaling and giving a courtship call for 1–2 seconds; it then moves around the colony and repeats the call. A male and female then stand face to face, with one extending its head and neck up and the other mirroring it; they both hold this posture for several minutes. Once in pairs, couples waddle around the colony together, with the female usually following the male. Before copulation, one bird bows deeply to its mate, its bill pointed close to the ground, and its mate then does the same.
  Contrary to popular belief, Emperor penguins do not mate for life; they are serially monogamous, having only one mate each year, and remaining faithful to that mate. However, fidelity between years is only around 15%. The narrow window of opportunity available for mating appears to be an influence, as there is a priority to mate and breed which usually precludes waiting for the previous year's partner to arrive at the colony.
  The female penguin lays one 460–470 g (1.01–1.04 lb) egg in May or early June; it is vaguely pear-shaped, pale greenish-white, and measures around 12 cm × 8 cm (4 ³⁄₄ in × 3 ¹⁄₄ in). It represents just 2.3% of its mother's body weight, making it one of the smallest eggs relative to the maternal weight in any bird species. 15.7% of the weight of an emperor penguin egg is shell; like those of other penguin species, the shell is relatively thick, which helps minimize risk of breakage.
  After laying, the mother's food reserves are exhausted and she very carefully transfers the egg to the male, and then immediately returns to the sea for two months to feed. The transfer of the egg can be awkward and difficult, especially for first-time parents, and many couples drop or crack the egg in the process. When this happens, the chick inside is quickly lost, as the egg cannot withstand the sub-freezing temperatures on the icy ground for more than one to two minutes. When a couple loses an egg in this manner, their relationship is ended and both walk back to the sea. They will return to the colony next year to try mating again. After the female departs for the sea and the male takes charge of their egg, he spends the dark, stormy winter incubating the egg in his brood pouch, balancing it on the tops of his feet, for around 65-75 consecutive days until hatching. The emperor penguin is the only species where this behaviour is observed; in all other penguin species both parents take shifts incubating. By the time the egg hatches, the male will have fasted for around 120 days since arriving at the colony. To survive the cold and savage winds of up to 200 km/h (120 mph), the males huddle together, taking turns in the middle of the huddle. They have also been observed with their backs to the wind to conserve body heat. In the four months of t
caption: The egg of the emperor penguin. It is 13.5 × 9.5 cm and vaguely pear-shaped. Muséum de Toulouse
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