Both of the marked bones came from large mammals. One fossil is a rib fragment, the other a femur shaft fragment. Both are marred by cut, scrape, and percussion marks. Microscope and elemental analysis using secondary electron imaging and energy dispersive x-ray spectrometry demonstrated that these marks were created before the bones fossilized meaning that we can eliminate recent damage as the cause of these marks. Dr. Hamdallah Bearat from the Ira A. Fulton Schools of Engineering at Arizona State University determined that one cut mark even contained a tiny, embedded piece of rock that was likely left behind during the butchering process.
"Most of the marks have features that indicate without doubt that they were inflicted by stone tools," explains Dr. Curtis Marean from the Institute of Human Origins at Arizona State University, who performed the mark identifications. "And the range of actions includes cutting and scraping for the removal of flesh, and percussion on the femur for breaking it to access marrow."
"The bones come from 2 animals, one (a femur) the size of a goat and the other (a rib) at least the size of a cow," notes Marean. "Our closest living relatives, the chimps and bonobos, don't hunt or scavenge animals this size, so this suggests that the Dikika australopithecines had already begun to engage in hunting or scavenging larger mammals. This places them in competitive and risky contexts."
While it is clear that the australopithecines at Dikika were using sharp-edged stones to carve meat from bo
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