Sea food was good for the mind

by Andrew Farrer

In the 1960s the importance of coastal sites for man living in the Middle Stone Age (250 – 35 thousand years ago) was realised. It seems, from the volume of the remains in human archaeological sites, that shellfish and other marine resources made these locales so appealing. It has been suggested that, more than being just a new food source, shellfish played a role in the evolution of the modern human.

Sea food contains much higher levels of the Omega-3 fatty acids than terrestrial food sources. Omega-3 is famous for being an excellent resource for developing brains; providing some of the building blocks required for maximising brain potential. As a result, living on the coast placed our ancestors in an environment ideal to evolve the complex, organic computer we are now so proud of.

Initially the quantity of Omega-3 consumed would have fulfilled the requirements of our ancestors’ smaller brains but over the generations, as the brain became more expensive, the need for shellfish would have increased. This presents a simple hypothesis: exploitation of marine resources should increase over time. The problem is that Middle Stone Age sites are not described in enough detail to really explore the connection. Worse still, the definition of key criteria varies between sites, making inter-site interpretation virtually impossible.

Hoedjiespunt 1(33° 01’ 42” S 17° 57’ 34” E) is on a peninsula in Saldanha Bay, South Africa. Approximately 68 miles North-West of Cape Town. Images from Google Earth

Figure 1: Hoedjiespunt 1(33° 01’ 42” S 17° 57’ 34” E) is on a peninsula in Saldanha Bay, South Africa. Approximately 68 miles North-West of Cape Town. (Images: Google Earth)

Researchers from the universities of Tuebingen and Cape Town reopened excavations at Hoedjiespunt 1 (see Figure 1 for information) in an effort to set the standard for study and reporting of archaeological data. Will et al. represents the first paper published as a result of this work and focuses on the interpretation of lithics (stone tools) and behaviour. Removing the soil in no more than 3 cm deep layers at a time the researchers found over 3,000 lithic artefacts distributed between three Archaeological Horizons (Archaeological Horizons are layers within the soil, much like strata in rock but formed by human activity). Three unique layers containing archaeologically relevant remains demonstrate that the site was habituated at least three distinct times (See Figure 2). The lithics, dating of shells and consideration of sea levels suggests Hoedjiespunt 1 was utilised 130 – 119 thousand years ago.

The lithics were of four main raw materials: quartz, quartz porphyry, calcrete and silcrete. Only silcrete is considered a good quality stone for knapping (tool preparation) and it is the only material not to be found on site (closest deposits are 6 – 18 miles away). Whilst evidence of all stages of production is found for the other materials, silcrete tools were made off-site. Interestingly the knappers have used different techniques for the differing materials, presumably to get the best results from each stone.

Will et al. suggest that the presence of silcrete shows our ancestors carried tools at all times. They would then have instruments directly available in unexpected situations encountered whilst travelling. Hoedjiespunt 1 seems to have required tool use in quantities that would be impractical to have carried from elsewhere. Poorer quality materials still made adequate tools (quartz forms sharp edges and can be retouched as it goes blunt); so, to me, this seems an economic decision, it was simply more cost effective to use poorer on-site materials than transport good quality ones.

Ocher (a natural pigment) was also found in a modified form. Often used for ritualistic or symbolic drawing it’s commonly seen as a sign of behavioural modernity. It can, however, also be used for hide tanning, insect repellent and as an adhesive. Ocher found at Hoedjiespunt 1 was mainly in the form of pencils though no evidence of design was found.

Figure 2: The three Archaeological Horizons (AH I-III) are clear in the excavation. Topped by a modern humus layer and with shelly sand (SHES) below. (Image: Will et al. 2013)

Figure 2: The three Archaeological Horizons (AH I-III) are clear in the excavation. Topped by a modern humus layer and with shelly sand (SHES) below. (Image: Will et al. 2013)

Whilst comparison between Hoedjiespunt 1 and other sites would reveal the most about changing behaviour at different times and places, this is difficult as the details of other sites are frequently not known in as much depth as Hoedjiespunt 1. However, a lot can be drawn from on-site finds. Data shows that the site was used regularly for short periods (perhaps at specific times of year to coincide with marine resource harvesting) by mobile hunter-gathers. Absolute and relative dating strongly suggests that these were H. sapiens; our direct ancestors. These people demonstrated the ability to plan and appreciate quality; as seen by the non-local preparation and transport of silcrete tools. Connecting lithics to marine resource harvesting is difficult but we can note several factors that support such a conclusion: the shellfish deposits are not natural, shellfish are burned, the three horizons are consistent (the site was used for the same purpose repeatedly) and the locale is best explained by marine resource exploitation as it is neither sheltered from the elements nor a suitable base for terrestrial hunting. In conclusion, our ancestors appear to have had a sustained and stable system that integrated marine resources as a main food source into their diets at Hoedjiespunt 1 and probably elsewhere.

The importance of this paper is not that it presents a ground breaking result (it does not) but that it represents a very important part of science that is often glossed over in our media fuelled world; collection of knowledge. All the sensational headlines seen in newspapers and blogs are born from lots of hard work and the building of a huge base of knowledge. Then a hypothesis and (possibly) a theory can be developed. This paper aims to continue the trend for much more in depth archaeological site review. Will et al. have not proved or disproved the Omega-3 hypothesis but they have certainly provided necessary steps to do so.

 

Reference:

Will, M. et al., 2013. Coastal adaptations and the Middle Stone Age lithic assemblages from Hoedjiespunt 1 in the Western Cape, South Africa. Journal of Human Evolution, (64), pp.518–537. Available at: http://www.sciencedirect.com/science/article/pii/S0047248413000924 [Accessed May 31, 2013].

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