Scarcer food pushed the first Homo sapiens to re-sharpen their stone tools

A Middle Stone Age in full transformation

About 300,000 years ago, the appearance of the first Homo sapiens in Africa coincided with profound cultural and technological changes. They mark the beginning of the Middle Stone Age, Africa's middle prehistory, a period when stone-knapping techniques diversified markedly.

These upheavals unfolded in landscapes that were themselves changing. To understand how our earliest ancestors adapted, researchers must reconstruct the environments they lived in, a approach at the heart of this research.

Landscapes with no modern equivalent

Today, the interior of central South Africa is dominated by vast arid steppes. Yet about 200,000 years ago, the region supported a significant share of shrubs and plants suited to milder conditions, along with a substantial supply of fresh water.

Rainfall was also spread more evenly through the year, the opposite of the current seasonal pattern. These so-called "non-analogue" landscapes correspond to no major type of present-day South African ecosystem. At Florisbad, these changes may have altered the availability of food resources and, consequently, the practices of the first Homo sapiens.

Reading the past in plant wax

To reach these conclusions, scientists analysed n-alkanes, molecules found in the wax that protects plant leaves and that are preserved in sedimentary layers. The different forms of carbon and hydrogen they contain provide information on past vegetation and climate.

Thanks to luminescence dating of sand grains, researchers assigned an age of about 200,000 years to certain layers at Florisbad, the site where one of the oldest skulls attributed to Homo sapiens was discovered in 1932.

Tools reworked according to resources

By comparing these reconstructed landscapes with the stone tools and faunal remains uncovered at Florisbad, the researchers identified a link between environmental productivity and knapping techniques. When food was probably less abundant or harder to access, tools were retouched more extensively.

This additional work made them more durable and allowed them to be reused. Conversely, when resources were more accessible, lightly retouched flakes, quicker to produce, were enough to cut meat. Our ancestors thus constantly adjusted their subsistence strategies to their changing ecosystems.

Towards other sites in southern Africa

According to the authors of the study, these results show the role environmental change may have played in the way of life of the earliest representatives of our species. Applied to other sites in southern Africa, this approach could shed light on the role of climate variability in the history of the first human populations.

For prehistory enthusiasts, Middle Stone Age tool collections are displayed in several South African museums, and sites in the region open new avenues for visits as research progresses.