An undated handout photograph shows the Nyayanga site on the Homa Peninsula of Lake Victoria in southwestern Kenya, where hundreds of stone tools dating to roughly 2.9 million years ago made by early human ancestors were found, also known as the Oldowan toolkit, were used to butcher hippos and pound plant material, according to new research led by an international team of scientists. J.S. Oliver, Homa Peninsula Paleoanthropology Project/Handout via REUTERS