Hominin evolutionary history in the Arabian Desert and the Thar Desert

Abstract

Climatic fluctuations, and the waxing and waning of desert environments, have important implications for our understanding of human evolution. Increasing aridity and the expansion of drylands results in impoverished habitats and a reduction of biodiversity. Human adaptations to arid conditions are generally thought to develop relatively late in our evolutionary history, being mostly confined to the Holocene (Barker and Gilbertson 2000, Veth et al. 2005), although there are hints that semiarid adaptations may go back into the Early Pleistocene (Yeshurun et al. 2011). On the whole, however, the majority of the archaeological evidence indicates that human populations tended to track favourable habitats, where animals and plants could be hunted and gathered and where fresh water supplies were readily available. This begs the question as to why Palaeolithic archaeologists and palaeoanthropologists should be interested in deserts. One significant reason concerns the notion that fluctuations in arid and humid landscapes have significantly shaped evolutionary processes. That is, climatic shifts and alterations in wet and dry habitats influence human demographic responses, leading either to the expansion, contraction or extinction of populations (Foley and Lahr 1998). Yet little is known about the relationship between climate change and human population history in the great desert regions of the world. Recent mapping of palaeohydrological features and archaeological sites in the Sahara have suggested that the expansion of human settlements is closely tied to moist habitats in the Holocene and Late Pleistocene (Kuper and Kropelin 2006, Osborne et al. 2008, Drake et al. 2011) and indeed the movement of hominins out of Africa is also thought to be closely related to the presence of humid corridors (Dennell 2009, Frumkin et al. 2010, Petraglia et al. 2010). On the other hand, the expansion of arid and hyper-arid landscapes may create geographic barriers, resulting in population fragmentation and isolation and even extinction. The aim of this chapter is to examine two desert regions that likely played a significant role in the Out of Africa story: the Arabian Desert and the Thar Desert. Although very little is presently known about the relationship between environmental change and human occupation in these desert regions, it is worth outlining what is known in order to begin the process of building a framework for future investigation.