"Also, by showing that A. afarensis was involved in these activities, we showed that you do not need a large brain to do this," added Alemseged, director of the Department of Anthropology at the California Academy of Sciences.
"This is a kind of find that will force us to revise our human evolution and anthropology textbooks."
He and his colleagues from the Dikika Research Project made the determinations while working in the Afar Region of Ethiopia. There they unearthed two fossilized bones bearing stone tool marks. One of the bones belonged to a large, buffalo-sized, hoofed mammal, while the other was possibly from an Impala, gazelle or antelope.
Various types of electron microscopy, along with chemical analysis, determined that cut marks were inflicted while one or more individuals carved meat off the bones with a sharp stone tool. Percussion marks were also created when a stone tool broke open the bones to extract their nutritious marrow.
The fossilized bones were found sandwiched between volcanic deposits, which permitted reliable dating of them. Before this discovery, the world's oldest human evidence for butchery dated to 2.5 million years ago and came from Bouri and Gona, Ethiopia. No human remains were found in association with those fossilized prey bones, but A. afarensis remains were previously unearthed near the recent Afar Region discoveries.