Sphenisciformes

(vertebrate zoology) The penguins, an order of aquatic birds found only in the Southern Hemisphere and characterized by paddlelike wings, erect posture, and scalelike feathers.

The penguins, a small monotypic order of flightless, marine swimming birds found in the southern oceans. Classification schemes that hypothesize a link between penguins and loons have no support in fact.

Penguins are medium-sized to large birds. They are completely flightless, their wings having been modified into stiff, flattened flippers. They stand upright on legs that are far posterior and that terminate in four toes, the anterior three of which are webbed. Penguins swim and dive well, using only their wings for propulsion: their feet are used only for steering. Terrestrial locomotion is by walking, hopping, or sliding on the belly while pushing with the wings. The plumage consists of dense, scalelike feathers that are black dorsally and white ventrally. A distinctive pattern or crest, often yellow, occurs on the head. Penguins are gregarious, breeding in large colonies along the coast. The males and females, which are identical, form strong pair bonds and share in the incubation and care of the downy nestlings. The older young of some species are kept in large groups, or creches. The emperor penguin (Aptenodytes forsteri) breeds on the ice pack along the Antarctic coasts during the fall. Incubation of the one or two eggs is the responsibility of the male, which remains on the nest for over 2 months in the winter without eating.

Penguins are found only in the cold southern oceans, on the Antarctic continent and its surrounding islands and northward to Australia, New Zealand, South America, and Africa. One species, the Galápagos penguins (Spheniscus mendiculus), is found in the Galápagos Islands, which are on the Equator but are surrounded by the cold Humboldt Current. See also Aves.