Antarctic Penguins - Paper

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Antarctic Penguins
Though penguins are assumed to be native to the South Pole, only four of the seventeen species have evolved the survival adaptations necessary to live and breed in the Antarctic year round. The physical features of the Adelie, Chinstrap, Gentoo, and Emperor penguins equip them to withstand the harshest living conditions in the world. Besides these four species, there are a number of others, including the yellow feathered Macaroni penguin and the King penguin that visit the Antarctic regularly but migrate to warmer waters to breed. Penguins that live in Antarctica year round have a thermoregulation system and a survival sense that allows them to live comfortably both on the ice and in the water. In the dark days of winter, when the Antarctic sees virtually no sunlight, the penguins that remain on the ice sheet sleep most of the day. To retain heat, penguins huddle in communities of up to 6,000 of their own species. When it's time to create a nest, most penguins build up a pile of rocks on top of the ice to place their eggs. The Emperor penguin, however, doesn't bother with a nest at all. The female Emperor lays just one egg and gives it to the male to protect while she goes off for weeks to feed. The male balances the egg on top of his feet, covering it with a small fold of skin called a brood patch. In the huddle, the male penguins rotate regularly so that none of the penguins have to stay on the outside of the circle exposed to the wind and cold for long periods of time. When it's time to take a turn on the outer edge of the pack, the penguins tuck their feathers in and shiver. The movement provides enough warmth until they can head back into the inner core and rest in the warmth. In order to reduce the cold of the ice, penguins often put their weight on their heels and tails. Antarctic penguins also have complex nasal passages that prevent 80 percent of their heat from leaving the body. When the sun is out, the black dorsal plumage attracts...
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