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Penguins (Order Sphenisformes, Family Spheniscidae) are a distinctive group of flightless birds, which occupy the southern hemisphere. There are generally accepted to be 17 species of penguin. In 1620, Admiral Beaulieu considered penguins to be feathered fish, due to their adaptations to life underwater. They have a streamlined bullet-like shape, and wings that have modified to become flippers. Penguins have an awkward, waddling gait on land, but underwater, they are graceful, and effectively fly underwater using their wings and flexible bodies. Penguins need to preen their feathers regularly with a waxy secretion, to keep them waterproof, and they have a thick layer of blubber, which keeps them warm. Their short, webbed feet are set far back to act as a rudder when in the water. The tuxedo-like coloration of penguins helps to make them less visible when in the water. When viewed from below, their white bellies blend in with the bright sea surface. When viewed from above, their black backs blend in with the dark sea. This makes it harder for predators including orcas (killer whales), sharks, leopard seals and sea lions to detect them, as well as camouflaging them from their prey. Species differences in physical appearances are usually concentrated on the head region, so that they are visible when the bird is swimming on the surface of the water and displaying face to face on land. Penguins can stay underwater for a maximum of 18 minutes, which is not as long as some marine mammals (seals can stay underwater for an hour). They only need to come to the surface for a few seconds before they can undergo another long dive. Some of the larger penguins, such as kings and emperors, can dive below 240m (almost 900 ft). The name penguin probably derived from the Latin word ‘pinguis’ or the Spanish ‘pinguigo’, which refers to the large quantity of fat on the birds. The name was used to describe the extinct great auk of the Northern Hemisphere first. |
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