47. Sphenisciformes (Penguins)

Supremely adapted diving birds of the cold oceans of the Southern Hemisphere, penguins form the only family within the order Sphenisciformes. Represented by some 18 to 20 living species, penguins pursue fish, squid, and crustacea under water. The modified wings that they use as flippers are useless for flight. Dense, short feathers and a heavy layer of fat insulate penguins from the extremely cold waters they inhabit. Although all penguin species are native to the Southern Hemisphere, they are not found only in cold climates, such as Antarctica. In fact, only a few species of penguin live so far south. Several species are found in the temperate zone, and one species, the Galápagos penguin, lives near the equator.