The Earth Institute at Columbia University announced Wednesday that scientists working in the desert badlands of northwestern Kenya have found stone tools dating back 3.3 million years, long before the advent of modern humans.
They are by far the oldest such artifacts yet discovered. The tools, whose makers may or may not have been some sort of human ancestor, push the known date of such tools back by 700,000 years. They also may challenge the notion that our own most direct ancestors were the first to bang two rocks together to create a new technology, Earth Sky reported.
The researchers do not know who made these oldest of tools. But earlier finds suggest a possible answer: The skull of a 3.3-million-year-old hominin, Kenyanthropus platytops, was found in 1999 about a kilometer from the tool site. A K. platyops tooth and a bone from a skull were discovered a few hundred meters away, and an as-yet unidentified tooth has been found about 100 meters away.
Ancient stone artifacts from East Africa were first uncovered at Olduvai Gorge in Tanzania in the mid-20th century, and those tools were later associated with fossil discoveries in the 1960s of the early human ancestor Homo habilis. That species has been dated to 2.1 million to 1.5 million years ago.
Subsequent finds have pushed back the dates of humans’ evolutionary ancestors, and of stone tools, raising questions about who first made that cognitive leap. The discovery of a partial lower jaw in the Afar region of Ethiopia, announced on March 4, pushes the fossil record for the genus Homo to 2.8 million years ago. Evidence from recent papers, the authors note, suggests that there is anatomical evidence that Homo had evolved into several distinct lines by 2 million years ago.
There is some evidence of more primitive tool use going back even before the new find. In 2009, researchers at Dikika, Ethiopia, dug up 3.39 million-year-old animal bones marked with slashes and other cut marks, evidence that someone used stones to trim flesh from bone and perhaps crush bones to get at the marrow inside. That is the earliest evidence of meat and marrow consumption by hominins. No tools were found at the site, so it’s unclear whether the marks were made with crafted tools or simply sharp-edged stones. The only hominin fossil remains in the area dating to that time are from Australopithecus afarensis.
