Though they are considered birds -- they lay eggs and have feathers -- penguins spend most of their lives at sea as fast and powerful predators -- a stark contrast to the clumsy, waddling penguin on land. The penguin's powerful flippers, gives them the ability to dive and hunt at ocean depths where no other bird can go.
No matter how awkward it is, every penguin must return to land. Each year penguins forsake the sea and struggle ashore to mate and lay eggs. Rockhopper penguins climb 90 foot cliffs to their nest; Adelies travel 3,000 perilous miles to breeding colonies.