Footprints uncovered in Kenya show that as early as 1.5 million years ago an ancestral species,almost certainly Homo Erectus,had already evolved the feet and walking gait of modern humans.
An international team of scientists,in a report on Friday in the journal Science,said the well-defined prints in an eroding bluff east of Lake Turkana provided the oldest evidence of an essentially modern humanlike foot anatomy. They said the find also added to evidence that painted a picture of Homo Erectus as the prehumans who took long evolutionary strides figuratively and,now it seems,also literally.
Where the individuals who made the tracks were going,or why,is beyond knowing by the cleverest scientist. The variability of the separation between some steps,researchers said,suggests that they were picking their way over an uneven surface,muddy enough to leave a mark an unintended message from an extinct species for the contemplation of its descendants.
Until now,no footprint trails had ever been associated with early members of our long-legged genus Homo. Preserved ancient footprints of any kind are rare. The only earlier prints of a protohuman species were found in 1978 at Laetoli,in Tanzania. Dated at 3.7 million years ago,they were made by Australopithecus afarensis,the diminutive species to which the famous Lucy skeleton belonged. The prints showed that the species already walked upright,but its short legs and long arms and its feet were in many ways ape-like.
Studying the more than a dozen prints,scientists determined that the individuals had heels,insteps and toes almost identical to those in humans,and that they walked with a long stride similar to human locomotion.
William L Junger,a paleoanthropologist at Stony Brook University in New York,said the footprints were further evidence that erectus had undergone a major structural change in body plan,and its much like our own. One obvious exception: the erectus brain,which was more advanced than those of previous ancestors,but was still much smaller than the Homo Sapien brain.