Research excavations like these in Siberia's Denisova Cave are yielding clues to the mating choices of early hominids. Bence Viola/Nature hide caption

itoggle caption Bence Viola/Nature

The first prehistoric chef who looked out at a field of grass in Africa and said, "dinner!" may have helped our ancestors use new resources in new locations. Roberto Schmidt/AFP/Getty Images hide caption

itoggle caption Roberto Schmidt/AFP/Getty Images