Woolly mammoths depended on tiny flowering plants for protein. Did the decline of the flowers cause their extinction? Per Möller/Johanna Anjar hide caption

itoggle caption Per Möller/Johanna Anjar

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