Penguins are insulated from the frigid ocean water by three layers of short, dense feathers and an underlying layer of fat. The wings are modified into stiff flippers for rapid swimming under water, while the webbed feet are used together with the tail as rudders for turning. Penguin habitat on South Georgia Island Penguin , common name for flightless, aquatic birds of the southern hemisphere. The name penguin originally was applied to the now extinct great auk of the North Atlantic, a large flightless, black and white bird with an upright stance. Similar flightless birds were discovered subsequently in the southern hemisphere, and they were also called penguins, a name that is now restricted exclusively to these birds.
Many species exhibit red, orange, or yellow patches on the head and neck.
Because their short legs are placed far back on their bodies, penguins assume an upright posture. Penguins are grouped into 18 species and 6 genera, most of which are found in Antarctica and on sub Antarctic islands. Others are native to the coasts of Australia, South Africa, and South America and to the Gal pagos Islands. Both species are found on the Antarctic ice barrier. The king penguin is also found in Tierra del Fuego and on eight islands in the southern hemisphere.