We found 2.9-million-year-old stone tools used to butcher ancient hippos—but likely not by our ancestors

On the shores of Lake Victoria in Kenya, a short valley extends south towards the looming Mount Homa. From it have emerged some of the oldest-known stone tools used to butcher large animals, as well as the oldest remains of one of our early cousins, Paranthropus—a genus we think co-existed with our direct ancestors.