Penguin was originally the common name for the now extinct great auk of the N Atlantic and now used, starting in the 19th cent., for the unrelated antarctic diving birds. Penguins are the most highly specialized of all birds for marine life. They swim entirely by means of their flipperlike wings, using their webbed feet as rudders. Their stiff feathers serve as insulation, and are waterproof when oiled. Since their legs are set far back on their bodies, they waddle awkwardly on land, and often travel by tobogganing on their bellies over the ice as they migratesometimes great distanceseach fall to their nesting sites.
Photographer: John Bird