Early humans had feet like ours and left lasting impressions in the form of 1.5 million-year-old footprints some of which were made by feet that could wear a size 9 men s shoe. The findings at a Northern Kenya site represent the oldest evidence of modern-human foot anatomy. They also help tell an ancestral story of humans who had fully transitioned from tree-dwellers to land walkers. “In a sense it s like putting flesh on the bones ” said John Harris an anthropologist with the Koobi Fora Field School of Rutgers University.
“The prints are so well preserved.” Almost human Harris and other colleagues report in the Feb. 27 issue of the journal Science on finding several footprint trails within two sedimentary rock layers. An upper sedimentary layer included two trails of two prints each one group of seven prints and a variety of isolated prints. The lower layer had a trail of two prints and a single isolated print likely from a smaller juvenile human. The researchers identified the footprints as probably belonging to a member of Homo ergaster an early form of Homo erectus. Such prints include modern foot features such as a rounded heel a human-like arch and a big toe that sits parallel to other toes. By contrast apes have more curved fingers and toes made for grasping tree branches. The earliest human ancestors such as Australopithecus afarensis still possessed many ape-like features more than 2 million years ago — the well-known “Lucy” specimen represents one such example.