A regional-scale mobility model for the early hominin occupation of the Lower Omo Valley (Ethiopia)

The ability of early hominins to adapt to diverse landscapes and ecological niches was a key factor in their range expansion. However, the behavioral and cognitive prerequisites underlying this adaptability remain poorly understood. Assuming that resource procurement played a pivotal role in hominin dispersal, we investigate the mobility-subsistence system of early Oldowan groups who occupied the Lower Omo landscape of southern Ethiopia some 2.3 million years ago (Ma). With its extensive archaeological record and scattered lithic resources, this context provides a landscape-scale record of early hominin behavior. Multiple lines of evidence derived from an integrated environmental, spatial and technological analysis indicate a regionally-structured mobility strategy, involving the provisioning of quartz pebbles and the transport of partially transformed products from distant sources to the biotic-rich but stone-poor margins of the paleo-Omo River, where highly mobile foraging activities were concentrated along the meandering channel. This regional strategy of early hominin displacement reflects a "Shungura exception" in the Early Pleistocene record. It coincides with the emergence of stone tool-mediated activities in the Lower Omo Valley, marking a tipping point in the capacity of early hominins to develop environment-specific adaptive strategies‒a crucial asset for their expansion into new ecological niches.