Raw Material Surveys and Their Behavioral Implications in Highland Lesotho

Abstract

Archaeologists have long considered climate change a primary mechanism behind human behavioral adaptations. The Lesotho highlands’ Afromontane and climatically extreme environments offer a unique opportunity to examine proposed correlations between topography, climate, and human behavior. Previous studies suggest that warmer temperatures allowed humans to expand their diet breadth and foraging range, whereas colder temperatures restricted humans to resources in riverine corridors. These studies used faunal and floral change as proxies to track changes in forager mobility but did not consider how differential access to stone resources affected human behaviors. To account for this gap, we conducted a survey for knappable rocks around the Sehonghong rock shelter in eastern Lesotho, recording the materials present and their size and shape in the modern environment. We compared the survey results to later Pleistocene (~ 22–11 ka cal. BP) lithic assemblages at Sehonghong to better understand whether archaeological patterns match modern knappable rock availability. Contrary to previous hypotheses, we find that past peoples at Sehonghong were not limited to exclusively riverine resources during colder conditions. We then used flake-to-core and noncortical-to-cortical flake ratios to track changes in mobility and knappable rock procurement patterns. The ratios remain constant up until the Late Glacial, ca. 14 ka cal. BP, when we see an increase in both flake-to-core and noncortical-to-cortical ratios, suggesting increased movement of stone out of Sehonghong. These conclusions show that resource procurement and mobility patterns are not solely dependent on climate change but may be driven by more complicated causal mechanisms such as increased interaction and the formation of social networks across the Lesotho highlands and beyond.