Ancient lakes are discovered in South Africa, indicating Stone Age humans
In some of South Africa's most dry locations, scientists have discovered ancient lakes, raising the possibility that Stone Age humans were more widespread than previously believed, according to a new study published in PNAS on May 15.
The research offers a rare picture of a diversified and productive area that may have sustained communities of prehistoric hunter-gatherers.
The mystery behind hunter-gatherers in South Africa
"This is currently the best evidence for when these lakes existed. This region has been something of a gap on the map, climatically and archaeologically," revealed lead author Dr. Andrew Carr from the University of Leicester School of Geography, Geology and the Environment in a press release.
Numerous studies have been conducted on South Africa's Stone Age archaeological record, especially for the past 150,000 years. This is partly because the country is home to several impressive coastline caves and rock shelter sites.
However, the existence of humans and the resources at their disposal in the vast interior regions of the nation have remained much more of a mystery—until now.
According to the most recent research, numerous sizable bodies of water were likely maintained during the last Ice Age in the now-arid interior of South Africa, particularly between 50,000 and 40,000 years ago and again 31,000 years ago.
Significantly, the team simulated how much water was needed to fill these palaeo-lakes, which made it possible to reconstruct the climatic changes required to form lakes and their effects on the region's hydrology, flora, and fauna.
They explored three lakes from the arid western interior of South Africa to as far east as Kimberley. They assessed the lakes' size and capacity and dated the shorelines using radiocarbon and luminescence dating techniques.

The conditions required to form the studied lakes would have produced significant changes in the region's numerous (now ephemeral or short-lived) rivers and lakes as the water table rose, according to computer simulations of regional hydrology.
"We know humans were present at times during the last ice age, as archaeological materials are scattered across the landscape surface. This new work hints at when and why humans used this landscape," Carr said.
He explained that while these places appeared inhospitable today, they seemed less hostile during past periods. Additionally, he added that this may have impacted how and when groups of people used the terrain, as well as how they interacted and shared ideas.
"It also tells us something about the sensitivity of ecosystems and environments to global climatic change," he stated. "You can see how these desert landscapes can respond in quite significant ways to global climate changes and understand how the human species responded and how adaptable it would have been."
It was also highlighted in the press release that the area is particularly difficult for archaeology because most materials are exposed on the surface of the desert and lack stratigraphic context, making it difficult to determine how long they have been there.
The complete study was published in PNAS on May 15 and be found here.
Study abstract:
Determining the timing and drivers of Pleistocene hydrological change in the interior of South Africa is critical for testing hypotheses regarding the presence, dynamics, and resilience of human populations. Combining geological data and physically based distributed hydrological modeling, we demonstrate the presence of large paleolakes in South Africa's central interior during the last glacial period, and infer a regional-scale invigoration of hydrological networks, particularly during marine isotope stages 3 and 2, most notably 55 to 39 ka and 34 to 31 ka. The resulting hydrological reconstructions further permit investigation of regional floral and fauna responses using a modern analog approach. These suggest that the climate change required to sustain these water bodies would have replaced xeric shrubland with more productive, eutrophic grassland or higher grass-cover vegetation, capable of supporting a substantial increase in ungulate diversity and biomass. The existence of such resource-rich landscapes for protracted phases within the last glacial period likely exerted a recurrent draw on human societies, evidenced by extensive pan-side artifact assemblages. Thus, rather than representing a perennially uninhabited hinterland, the central interior's underrepresentation in late Pleistocene archeological narratives likely reflects taphonomic biases stemming from a dearth of rockshelters and regional geomorphic controls. These findings suggest that South Africa's central interior experienced greater climatic, ecological, and cultural dynamism than previously appreciated and potential to host human populations whose archaeological signatures deserve systematic investigation.