Reconceptualising the palaeozoogeography of the Sahara and the dispersal of early modern humans

Abstract

Abstract Genetic and archaeological lines of evidence both suggest that Homo sapiens dispersed out of Africa sometime between 130 and 50 ka, and that a likely route was across the ‘green Sahara’. However, there is an absence of definitive evidence for trans-Sahara dispersal even though some animal species appear to have done so. To further our understanding of this dispersal, we present a model that considers the different ways humans can affect animal distributions and vice versa. We define three different mechanisms: facilitation, co-distribution and translocation. We then use North Africa during the last two interglacial humid phases as a testbed to evaluate each mechanism by analysing animal, fossil and rock art distributions, molecular phylogeny, archaeology and linguistics. We demonstrate strong evidence for facilitation with some evidence for co-distribution and translocation. Facilitation during the penultimate interglacial can be associated with the dispersal of H. sapiens out of Africa. Keywords : Dispersal, facilitation, co-distribution, translocation, Sahara INTRODUCTION Saharan palaeozoogeography has traditionally been pursued through phenotypic and distributional analyses of modern and fossil animal species. A revolution in our understanding in this area has been brought about by a significant increase in genetic analyses of desert species, new models of the palaeohydrology of the Sahara and a better knowledge of the role of hominins in the dispersal of a wide variety of species. Ancillary disciplines, such as rock art studies, continue to provide new insights into the presence of larger species and human interactions with them. Synchronic ethnography also brings models of human/animal interactions to bear on the modelling of past relationships. This chapter is intended to bring together these new findings and put forward a preliminary analysis of the relationship between human and animal dispersal in the early Sahara. Genetic and archaeological studies suggest that Homo sapiens dispersed out of Africa sometime between 130 and 50 ka (Macaulay et al. 2005; Gunz et al. 2009; Boivin et al. 2013). This is likely to have been preceded by at least three waves of hominin dispersals out of Africa between 1.9 and 0.7 Ma (Bar-Yosef and Belfer-Cohen 2001), with the possibility of an earlier wave around 2.5 Ma (Dennell 2009), and with additional suggestions of further migrations around 780–700 ka (Martinez-Navarro and Rabinovich 2011) and 600 ka (e.g., Lahr and Foley 1998) and.