Archaeologists have discovered the oldest known evidence for highly skilled stone tool making, dating to more than 2 million years ago. The find, announced in tomorrow's Nature, raises questions about whether hominids predating the genus Homo, to which modern humans belong, could have acquired such skills.
Clearly, some pre-Homo hominids had a rudimentary knack for it, because crude stone tools date back 2.6 million years--about 300,000 years before the appearance of Homo habilis, the earliest undisputed Homo species. But only members of the genus Homo were thought to possess the skills required to manufacture the array of blades, scrapers, and other standard tools used for hunting and gathering.
Maybe not. Excavating in 1997 near Lake Turkana in Kenya, an international team led by Hélène Roche of the House of Archaeology and Ethnology in Nanterre, near Paris, unearthed a cache of stone tools in a 2.34-million-year-old layer of volcanic sediment. Debris was so well preserved that the team could reconstruct more than 60 original stones, mostly chunks of lava, from which tools had been fashioned. The handiwork suggests considerable forethought and precision movements to strike stones together and produce well-crafted implements. "No one has previously identified such skill ... in artifacts that are so old," writes archaeologist James Steele of the University of Southampton, United Kingdom, in an accompanying commentary in Nature.
The findings raise the intriguing possibility that pre-Homo hominids made the tools, says Roche. In the Lake Turkana region, fossils of Homo habilis as old as 2.3 million years have never been found, although traces of older hominids, the australopithecines, are well known from this time. Roche thinks australopithecines may have possessed the toolmaking skills demonstrated by the recent find. "Maybe we just have to face the evidence," she says.