HUMAN EVOLUTION Vol. 28 n.3-4 (137-170) - 2013 Oppenheimer S. Human’s Association with Water Bodies: Institute of Cognitive and Evolutionary The ‘Exaggerated Diving Reflex’ and Anthropology, School of Anthropology and Museum Ethnography, its Relationship with the Evolutionary University of Oxford, UK. Allometry of Human Pelvic and Brain Sizes E-mail:
[email protected] As Darwin suggested, humans first evolved in Africa, then quickly spread out. Occupation sites from the Palaeolithic to the present show a niche preference for proximity to water bod- ies, rivers, lakes and sea coasts. From 165 Kya there is clear evidence for shellfish use, with characteristic shell middens in littoral zones. Genetic phylo-geography for Anatomically Modern Humans (AMH) indicates there was a single definitive exit from near the Horn Africa about 70 Kya, moving, with ex- traordinary rapidity, along coastlines around the Indian Ocean to Bali, later to China and the Americas. They crossed the sea to New Guinea and Australia by 50 KYA. Although AMH were not the first humans to cross Wallace’s Line, they were the first to make open-sea voyages of over 100 miles. Why are anatomi- cally modern humans associated with water bodies? Is it to do with their daily need for fresh drinking water? Is there any spe- cial significance to their exploitation of the food they find there, or is it just making the best of their niche? What aspect of their past evolution explains their ‘exaggerated mammalian diving reflex’? How is it connected with water? The pan-vertebrate reflex cardio-vascular response to extreme hypoxia has long been acknowledged as essential protection in terrestrial vertebrates against the risk of perinatal asphyxia as their milieu changes from aqueous to air.