Assessment of the Southern Dispersal: GIS-Based Analyses of Potential Routes at Oxygen Isotopic Stage 4

This paper explores the geographic and environmental context of the Southern Dispersal Route, which has been proposed as a migratory route for Homo sapiens from East Africa to Australasia during oxygen isotope stage (OIS) 4 (71–59 kyr). A series of assumptions and constraints garnered from modern hunter-gatherer observations are used to build a model of coastal foragers, which is then integrated with high-resolution physiographic analyses to produce a potential dispersal route along the coastline of the Indian Ocean. Paleoenvironmental conditions that may have supplied critical resources or served as obstacles to human colonization are identified and discussed in regards to human subsistence, the speed of migration, and demographic expansion. These factors suggest that rapid dispersals along coastlines and river valleys would have occurred upon the initial expansion out of Africa, but slowed as populations expanded demographically into South Asia and the Sunda Shelf. This also suggests that archaeological signatures relating to the earliest modern Homo sapiens are more likely to be recovered in South Asia.     

The Archaeology of Aquatic Adaptations: Paradigms for a New Millennium

Although aquatic resources are often seen as central to the development of post-Pleistocene cultural complexity, most models of human evolution have all but ignored the role of aquatic or maritime adaptations during the earlier stages of human history. When did aquatic resources, maritime adaptations, and seafaring first play a significant role in human evolution? I explore this fundamental question by (1) reviewing various theories on the subject; (2) discussing a variety of problems that prevent archaeologists from providing a clear answer; and (3) examining the archaeological record for evidence of early aquatic resource use or seafaring. I conclude that aquatic resources, wherever they were both abundant and relatively accessible, have probably always been used opportunistically by our ancestors. Evidence suggests, however, that aquatic and maritime adaptations (including seafaring) played a significantly greater role in the demographic and geographic expansion of anatomically modern humans after about 150,000 years ago. Another significant expansion occurred somewhat later in time, with the development of more sophisticated seafaring, fishing, and marine hunting technologies.