This story was originally published on The Conversation. It appears here under a Creative Commons license. Just over two decades ago, as the new millennium began, it seemed that tracks left by our ancient human ancestors dating back more than about 50,000 years were excessively rare. Only four sites had been reported in the whole of Africa at that time. Two were from East Africa: Laetoli in Tanzania and Koobi Fora in Kenya; two were from South Africa (Nahoon and Langebaan). In fact the Nahoon site, reported in 1966, was…
