Footprints prove earliest humans walked 1.5 mn years ago
Footprints found by researchers in two 1.5 million-year-old sedimentary layers in Kenya show that some of the earliest humans walked like we do today.
The footprints found near Ileret in northern Kenya constitute the oldest evidence of an essentially modern human-like foot anatomy. These rarest of impressions yielded information about soft tissue form and structure not normally accessible in fossilised bones.
To ensure that comparisons made with modern human and other fossil hominid footprints were objective, the Ileret footprints were scanned and digitised by the study's lead author Matthew Bennett, a professor at Bournemouth University in Britain.
An optical laser scan showed two right footprints and a partial left along with a range of animal prints. This anatomical interpretation was the conclusion of John W.K. Harris, professor of anthropology at Rutgers University in New Jersey, US, and an international team of colleagues.
The researchers reported that the upper sediment layer contained three footprint trails: two trails of two prints each, one of seven prints and a number of isolated prints.
Five metres deeper, the other sediment surface preserved one trail of two prints and a single isolated smaller print, probably from a juvenile.
In these specimens, the big toe is parallel to the other toes unlike that of apes, where it is separated in a grasping configuration useful in the trees. The footprints show a pronounced human-like arch and short toes, typically associated with an upright bipedal stance.
The size, spacing and depth of the impressions were the basis of estimates of weight, stride and gait, all found to be within the range of modern humans, said a Rutgers statement.
Other institutions involved in this research included the George Washington University, Liverpool John Moores University, Smithsonian Institution, University of Cape Town and University of Nairobi. These findings featured as the cover story in Thursday's edition of Science.