Read our open access article, available for download here: https://doi.org/10.1371/journal.pone.0241068
Stone points in South Africa show ancient humans’ innovative adaptations to an arid environment
Our new study reports that ancient humans in South Africa were making stone points using a distinctive method known as ‘Nubian technology’ which we argue shows a specific adaptation to desert conditions. Archaeological research in the Tankwa Karoo – today one of the most arid parts of South Africa – reveals that around 50,000 years ago, people were adapting their existing customs to make pointed tools using an entirely different method. Currently, this is only known at a handful of sites in this area, including one major tool-making site, Tweefontein, described in the research published in the journal PLOS ONE.
Originally named for its occurrence in the Nile Valley, Nubian technology has recently been found in Arabia and Israel, prompting theories about a ‘trail of breadcrumbs’ left by migrating populations around 120-70,000 years ago. However, we suggest that the presence of this technology in South Africa, some 6000 km away, is not the result of migrations but rather shows its independent invention many thousands of years later. The site of Tweefontein was discovered by authors Dr Emily Hallinan and Matthew Shaw in 2014 when we reported the first identification of Nubian technology in southern Africa. This new in-depth study of the stone tools at Tweefontein shows that these follow the same characteristic patterns as Nubian technology elsewhere, used to make hundreds of stone points. We argue that this is significant as it demonstrates a local innovation to deal with the specific challenges of being a hunter-gatherer in a desert environment. The fact that Nubian technology occurs in desert contexts in North Africa, Israel and Arabia could suggest that populations came up with the same technological solution under these conditions, known as convergent evolution. Considering how past humans were able to adapt their ways of making tools under the environmental challenges they faced is key to understanding how our species was ultimately able to disperse across the globe.
We carried out surveys recording thousands of stone tools on the land surface in the Tankwa Karoo, situated between the Cederberg and Roggeveld Mountains on the Western and Northern Cape Province border. While often archaeologists studying this period, known as the Middle Stone Age, focus on excavating cave sites, our alternative approach allows us to look at how past hunter-gatherers moved around the landscape as a whole. In addition to the mass-production of hundreds of points at Tweefontein, Nubian technology was recognised at twelve other locations where much smaller numbers of cores and points were discarded. In spite of numerous cave excavations elsewhere in South Africa, only one Nubian core has been reported from a site nearby, emphasising the important new perspectives that can be gained from studying sites in the open-air.