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Latest News [ Back To News Index ] For more news articles click the News Index link above. How tools and meat-eating made us human  New finds from Ethiopia have shown that the world's oldest stone tools were made by hominids that selected their raw materials carefully and understood how they could be used. While little is known about the first toolmakers, they seem to have used their new skills to obtain a meat-rich diet. Ethiopian archaeologist Sileshi Semaw reports that sites on the Kada Gona River in north-eastern Ethiopia have yielded numerous stone flakes and cores. Based on radioisotopic argon-argon dating and the correlation of the Earth's ancient magnetic field with the deposits, in which the tools were found, he dates them to between 2.6 and 2.5 million years ago. The tools were largely made from trachyte, a stone that flakes neatly when struck with a stone hammer to give sharp-edged fragments that can be used immediately for cutting. Dr Semaw concludes, "Ancestral toolmakers selected raw materials with good flaking quality, chose appropriate size cobbles when making artefacts, sought for acute angles when striking the cobbles and produced sharp-edged implements used for cutting. The makers travelled long distances to acquire raw materials, implying mobility, long-term planning and foresight not recognised earlier." The purpose of the tools was the production of sharp edges which could be used for cutting up carcasses, for their nutritious meat, although whether this was from animals that had been hunted, or from scavenging on such useful things like lion kills, is not yet established. The site of Bouri, also in Ethiopia and dating to 2.5 million years ago, has yielded bones with cut-marks on them, indicating that purposeful meat eating began at least this early. "Further detailed research is needed to determine why meat became an important food item by this time and how it was acquired. It is also not clear whether the First tools were used for processing plant foods as well, although the habitat of the first toolmakers along watercourses would have meant such foods were available. Exactly who they were is also a matter of debate, although Dr Semaw is clear that Australopithecus afafensis, the species whose most famous member is "Lucy" - the 3.75-million-year-old skeleton found a quarter of a century ago in a neighbouring region of Ethiopia - was not a candidate. He believes that the newly discovered Australopithecus garhi and the first kinds of Homo are likely to have been responsible. Tools made by Homo have long been known from other sites from 2.4 million years ago onwards, "therefore early Homo may be uncontested as the maker and user of stone artefacts, but the case for Australopithecus garhi as the first toolmaker is also compelling," Dr Semaw says. Recent evidence identifying which parts of the brain were used in early tool making, and the fact that these are also the areas that have undergone explosive evolution in the past 2.5 million years, suggests that craftsmanship and mental development were correlated. Since the brain is known to be very energy-expensive, as the result of work by Dr Lesley Aiello at University College London, it seems possible that the adoption of a protein-rich diet may have been the other vital factor in making hominids into recognisable humans. [ Back To News Index ] |
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