<P> The emperor penguin (Aptenodytes forsteri) 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 122 cm (48 in) in height and weighing from 22 to 45 kg (49 to 99 lb). The dorsal side and head 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 . </P> <P> Its diet consists primarily of fish, but can also include crustaceans, such as krill, and cephalopods, such as squid . In hunting, the species can remain submerged up to 18 minutes, diving to a depth of 535 m (1,755 ft). 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 . </P> <P> The only penguin species that breeds during the Antarctic winter, emperor penguins trek 50--120 km (31--75 mi) over the ice to breeding colonies which may include thousands of individuals . The female lays a single egg, which is incubated by the male while the female returns to the sea to feed; parents subsequently take turns foraging at sea and caring for their chick in the colony . The lifespan is typically 20 years in the wild, although observations suggest that some individuals may live to 50 years of age . </P> <P> Emperor penguins were described in 1844 by English zoologist George Robert Gray, who created the generic name from Ancient Greek word elements, ἀ - πτηνο - δύτης (a-ptēno - dytēs), "without - wings - diver". Its specific name is in honour of the German naturalist Johann Reinhold Forster, who accompanied Captain James Cook on his second voyage and officially named five other penguin species . Forster may have been the first person to sight the penguins in 1773--74; he recorded a sighting of what he believed to be A. patagonicus but, given the location, may well have been A. forsteri . </P>

What is the life cycle of the emperor penguin