Rutgers University students discover ancient footprint in Kenya
"We knew we might have something special, but we also kept thinking, 'OK, these could be from a baboon,'" Braun said.
Turns out all that caution was unnecessary. Over three summers, Braun and his colleagues unearthed a bit of archaeological gold: what's believed to be the first known footprints of Homo erectus, an ancestor to modern humans. The finding was reported Friday in the journal Science.
The researchers, who included Rutgers professor John W.K. Harris and a team of international experts, determined the feet that left those prints 1.5 million years ago were almost exactly like ours, with nearly identical heels, insteps and toes. Significantly, the big toe ran parallel with the other toes, suggesting a modern upright gait.
The footprints also indicated that those who left them took long strides like modern humans, allowing them to run and travel long distances. That squares with the fossil record, which shows that Homo erectus began migrating out of Africa about 1.8 million years ago.
Only one cluster of older pre-human footprints has ever been found. They were discovered in 1978 in Laetoli, Tanzania, and had been left 3.7 million years ago by Australopithecus afarensis, the small, apelike species to which the famous skeleton "Lucy" belonged.
It was in the summer of 2005 that the researchers made their discovery a few miles east of Lake Turkana, though they didn't know initially how big it would be. The group was cutting into the wall of a bluff to examine the geology of the area when they noticed deformations in the sediment.
"It was odd-looking," said Braun, the son of a Star-Ledger columnist, Bob Braun. "We were looking at it from the side, and it wasn't until we excavated from the top that we realized these were footprints."
A fuller excavation began in the summer of 2006, followed by two more in 2007 and 2008. Their excitement growing, Harris and Braun turned to other experts for help.
Matthew R. Bennett, a professor from Bournemouth University in England, used a digital laser scanner to create three-dimensional images of the footprints in 2007, showing them in detail.
In all, the group found more than a dozen prints on two layers of sediment separated by about 10,000 years. In one layer, they found two trails of two footprints each and one that included seven prints. Three prints were found on the lower layer.