Coastal resources and nutrition among Middle Stone Age hunter-gatherers in the Southwestern Cape

Doctoral Thesis


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University of Cape Town

This thesis presents new information on the macronutrient, micronutrient and fatty acid content of marine and terrestrial resources available to Middle Stone Age hunter-gatherers in the southwestern Cape, and examines the role of coastal and terrestrial foods in the diets of early modern humans in the region. The collection, consumption and systematic discard of intertidal molluscs by prehistoric people is firmly attested by the presence of shellfish residues at archaeological sites dating to the Last Interglacial (120 000 years ago) at Klasies River Mouth, Blombos Cave, Hoedjiespunt and Sea Harvest, or earlier (164 000 years ago) at Pinnacle Point. The incorporation of marine foods into the diet is one of several forms of innovative behaviour characteristic of the Middle Stone Age. Classification of fossil hominin remains from key sites in southern Africa as anatomically modern further marks the Middle Stone Age as a crucial stage in the evolution of our species. The apparent link between coastal resources, innovative behaviour and anatomical modernity is tantalising, and in need of further exploration. The nutrient content of one hundred and twenty three samples from a range of marine and terrestrial animals and plants known or presumed to have been eaten by Middle Stone Age hunter-gatherers in the southwestern Cape was measured using spectrophotometry and gas chromatography. When interpreted against existing knowledge on prehistoric subsistence strategies and ecology, these results provide a quantitative framework within which the relative utility of marine and terrestrial resources as a nutritional substrate for encephalising humans is evaluated. While terrestrial foods would have provided prehistoric people with sufficient energy and trace elements, sources of long-chain polyunsaturated fatty acids would have been limited. Marine foods, including intertidal mussels and limpets, are rich in the two most important omega-3 fatty acids found in the human brain, namely eicosapentaenoic and docosahexaenoic acid. The inclusion of coastal resources, particularly sessile, abundant, predictable and easily collected marine molluscs, in the diet would have been highly advantageous for groups of early modern humans in the vicinity of the Atlantic west coast. Pregnant and lactating women and very young children, who have some of the highest requirements for brain-specific nutrients, are likely to have benefitted the most.

Includes bibliographical references.