Pub. date: 2006 | Online Pub. Date: September 15, 2007 | DOI: 10.4135/9781412952453 | Print ISBN: 9780761930297 | Online ISBN: 9781412952453 | Publisher:SAGE Publications, Inc.About this encyclopedia
Kevin D. Hunt
Among living primates, only humans are bipedal. It is not certain when this unique feature emerged, but it must have been before the 3.6 million-year-old Laetoli footprints were made. Although the prints were not made by completely modern feet, they are unequivocally the prints of bipeds. They are the impressions of feet that lacked a distinctive human rounded ball, or swelling, at the base of the great toe, that had no well-defined arch, and that retained ever so slightly divergent great toes. Somewhat later in time, the well-known 2.9 million-year-old Australopithecus afarensis Lucy fossil is the earliest human ancestor to display the clear skeletal hallmarks of bipedalism. Earlier fossils are either not yet described or lack the two most diagnostic parts, the pelvis and the distal (i.e., lower) femur. Despite the paucity of fossils near the beginning of the human lineage, most paleontologists regard bipedalism as the earliest distinctively human ...