More than three million years ago, our ancient human ancestors stood on two feet and walked upright. But new analysis of a child's foot from a 3.3 million-year-old fossil skeleton shows that our ancestors, at least the youngest ones, still had adaptations to help them climb trees like their apelike cousins.
The tiny foot, about the size of a human thumb, is part of a nearly complete 3.3 million-year-old skeleton of a young female Australopithecus afarensis. Zeresenay (Zeray) Alemseged, professor of organismal biology and anatomy at the University of Chicago and senior author of the study, discovered the fossil in 2002 in the Dikika region of Ethiopia.
“The skeleton continues to provide new, really amazing insight in terms of the many adaptations that our early human ancestors had,” Alemseged said. “Now to identify features that are slightly apelike in an otherwise very humanlike creature is a bit of a surprise.”