The genus Aptenodytes
, which consists of the Emperor
Penguins, differs in many respects from the other living penguins. Apart from their outstanding size, their long slender bill and colourful plumage are their most apparent characteristics. No other bird can dive for as long or as deep as Emperor and King Penguins. In contrast to all other penguins, they lay only a single egg and build no nest at all, balancing their egg and, later, the chick, on their feet. The breeding biology of these two species is quite different from each other but both are extreme. They also have behavioural characteristics not found in other penguin species.
Both species have a circumpolar distribution: the King Penguin in the sub-Antarctic, restricted to islands; the Emperor Penguin in the high Antarctic.
Moult is pre-nuptial in King Penguins, post-nuptial in Emperor Penguins. Emperor Penguins often moult away from the breeding colonies.