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 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. The relationship of penguins to other groups is not yet well understood.