In this 2007 file photo the 3.2 million year old Australopithecus afarensis skeleton called Lucy and an artist's life-sized model (r.) are displayed at the Houston Museum of Natural Science in Houston. Lucy's feet were made for walking. That's the word from a team of researchers that has gotten the first look at a foot bone from an human relative that lived three million or more years ago.Michael Stravato/AP/File