Shellfish collecting at Blombos Cave – possible insights into Late Pleistocene subsistence

Understanding the subsistence behaviour of anatomically modern humans living at Blombos Cave (BBC) (South Africa) during the Middle Stone Age (MSA) may shed light on their foraging efficiency. Analysis of the shellfish remains may inform us about the way people gathered. These results can be used to assess their knowledge of the environment and assess their ability to plan, coordinate, execute and optimise their foraging activities. Here I report an analysis, ranking 19 shellfish species in terms of species preference, meat weight, caloric value, size, encounter rate, extraction effort, location of occurrence and seasonal peaks. The selected species are common
in most BBC levels and exploited by contemporary local communities. I measure these variables by comparing the minimal number of individuals of each represented species. The ranking will run from low to high, indicating difficult to more easy to obtain and process prey. The samples come from BBC levels 1-3 (~78.8 ka to ~72.7 ka), creating a diachronic overview of MSA shellfish subsistence at BBC. If low ranked species are common, then there probably was a preference for more difficult to collect, yet perhaps more rewarding in terms of meat and caloric returns, prey. In this scenario it is likely that the people at BBC had a good understanding of the coastal environment and its resources. They planned their foraging sessions using this knowledge extensively. If they show no preference for particular species and if high ranked species are
common then it is unlikely that the people at BBC were as efficient gatherers as modern hunter gatherers. It would imply ad hoc foraging behaviour in which people roamed the coast randomly and showed no planning depth in terms of shellfish handling costs and seasonal and monthly peaks.