Siberia's Denisova cave held the pinky bone of an unknown early human species, a genetics team reported in March. The Naturejournal study, led by Johannes Krause of Germany's Max Planck Institute for Evolutionary Anthropology, offered no answer for what happened to this "archaic" human species, more than one million years old and living near their human and Neanderthal cousins as recently as 30,000 years ago. More on Evolution