Penguins were first documented in 1520 by explorer Ferdinand Magellan who sighted the fascinating birds on one of his many ocean voyages. Most live in habitats free of land predators where their inability to fly is not detrimental to survival. Contrary to popular belief, penguins cannot be found at the North Pole or in Alaska. Penguins' bodies are densely covered by feathers, sometimes as many as 70 per square inch. Penguin species can be differentiated by their head and facial markings as well as their size.
Penguins have wings or paddle-like flippers which they use to swim.
Their feet are webbed and positioned near the tail to aid in steering in water. Penguin bones are heavier than the air-filled skeletons of flying birds. On land, most penguins walk standing upright while some species toboggan on their stomachs, and yet others hop as a form of locomotion. Penguins have good hearing, little or no sense of smell, vision believed to be better suited for water than air, and a poorly developed sense of taste. Penguins are considered the most social of all birds.