Testing a refugium model for the dispersal of Late Pleistocene huntergatherer

Over the last decade, many scholars have pointed to the “Southern Corridor” as the most likely dispersal route of anatomically modern humans out of Africa, across the Red Sea and into Arabia ~70-50 kya. However, little attention has been paid to the environmental and social contexts from which these African founder populations emerged. Our refugium model for Late Pleistocene Homo sapiens aggregation and dispersal, proposes two competing hypothesises. The first argues that the hyperarid and cold conditions of OIS 4 ~ 70-60 kya made much of northern Africa, the Horn and parts of Central and East Afirca uninhabitable for large hunter-gatherer groups. The wetter SW Ethiopian highlands served as a paleoenvironmental refugium that attracted culturally diverse hunter-gatherer groups from surrounding regions. We suggest that contact between these culturally diverse foraging groups may have stimulated technological and social innovations. Armed with these technological and social skills, hunter-gatherer populations would have been able to successfully and rapidly adapt to a wide range of conditions as they migrated out of the SW Ethiopian highlands across and out of Africa. The second hypothesis suggests it wasn’t until the beginning of OIS 3 ~ 60-50 kya that ameliorating but rapidly fluctuating paleoecological conditions provided the stimulus necessary for SW Ethiopian hunter-gatherer groups to develop the key social and technological innovations necessary for successful dispersal through and out of Afirca. After outlining this model, we discuss our current research initiative in SW Ethiopia designed to test these hypotheses. This includes paleoenvironmental research as well as archaeological surveys and excavations in and around Moche Borago Rockshelter.