Midden or Molehill: The Role of Coastal Adaptations in Human Evolution and Dispersal

Coastal adaptations have become an important topic in discussions about the evolution and dispersal of Homo sapiens. However, the actual distribution and potential relevance of coastal adaptations (broadly, the use of coastal resources and settlement along shorelines) in these processes remains debated, as is the claim that Neanderthals exhibited similar behaviors. To assess both questions, we performed a systematic review comparing coastal adaptations of H. sapiens during the African Middle Stone Age (MSA) with those of contemporaneous Neanderthals during the European Middle Paleolithic. In both species, systematic use of marine resources and coastal landscapes constitutes a consistent behavioral signature over?~?100,000 years (MIS 6–3) in several regions of Africa and Europe. We found more similarities than differences between Neanderthals and modern humans, with remaining disparities all in degree rather than kind. H. sapiens exploited a wider range of marine resources—particularly shellfish—more intensively. MSA shellfish-bearing sites are also more often associated with intense occupations on coastal landscapes, and more evidence of complex material culture such as shell beads. In terms of broader ramifications, Pleistocene coastal adaptations are best conceived of as an ‘add-on’ to previous adaptive strategies, complementing more frequently exploited inland resources and landscapes. Still, Neanderthals and modern humans increased their dietary breadth and quality, and added options for occupation and range expansion along coastlines. Potential evolutionary implications of these multi-generational behaviors include higher intakes of brain-selective nutrients as a basis for neurobiological changes connected to increased cognitive capacities, but also greater reproductive success, dispersal abilities and behavioral flexibility. Whether gradual differences between modern humans and Neanderthals stimulated different evolutionary trajectories is a question for future research.