The rendering industry likes to call itself the world's oldest recycling system. Nearly 100 percent of processed pigs will eventually get used — as meat and in uses as varied as medicine and pet food. iStockphoto hide caption

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A manatee swims underwater in the springs of Crystal River, Fla. — home to a group of residents who have sued the U.S. Fish and Wildlife Service, demanding that the agency consider removing the animals from the endangered species list. Amanda Cotton/iStockphoto hide caption

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The French enjoy horse meat — here's a horse meat butcher in Paris. But even the French were angry that they had been paying beef prices for it last year. Thomas Coex/AFP/Getty Images hide caption

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Mammuthus columbi, the Columbian mammoth, used to be common in America, but went extinct about 10,000 years ago. The specimen found south of Dallas is estimated to be 20,000 - 40,000 years old. Illustration by Karen Carr/Perot Museum of Nature and Science hide caption

itoggle caption Illustration by Karen Carr/Perot Museum of Nature and Science