A file photo from 2011 shows a man touching a giant bronze sculpture of a mammoth in the Siberian city of Khanty-Mansiysk. A team of Russian and South Korean scientists who found a well-preserved frozen woolly mammoth carcass this month say it also included blood. Natalia Kolesnikova/AFP/Getty Images hide caption

itoggle caption Natalia Kolesnikova/AFP/Getty Images

Channel-billed toucans are important seed dispersers in rain forests. Courtesy of Lindolfo Souto/AAAS/Science hide caption

itoggle caption Courtesy of Lindolfo Souto/AAAS/Science

Whenever a steer or cow leaves a farm in Michigan or goes to a slaughterhouse, it passes by a tag reader, and its ID number goes to a central computer that keeps track of every animal's location. Dan Charles/NPR hide caption

itoggle caption Dan Charles/NPR