Modern humans '44 000 years ago'
31 July 2012
An international team, including scientists from South Africa's Wits University, has published research that substantially increases the age at which we can trace the emergence of behaviourally modern humans - through direct links to the San people of southern Africa.
The question of when and where anatomically modern humans first emerged (Africa, about 200 000 years ago, the evidence indicates) still leaves open the question: when and where did human cultures similar to ours emerge?
Until now, most archaeologists believed the oldest traces of San hunter-gatherer culture in southern Africa dated back 10 000 or at most 20 000 years.
The new research - published online in the prestigious journal Proceedings of the National Academy of Sciences on Monday - pushes this much further back in time, to 44 000 years ago.
Border Cave, South Africa
The research team, comprising scientists from South Africa, France, Italy, Norway, the USA and Britain, drew its conclusions from archaeological material discovered at Border Cave in South Africa.
Located in the foothills of the Lebombo Mountains in KwaZulu-Natal province, the site has yielded exceptionally well-preserved organic material.
According to Lucinda Backwell, a senior researcher at Wits University's Bernard Price Institute for Paleontological Research, the dating and analysis of this material "has allowed us to demonstrate that many elements of material culture that characterise the lifestyle of San hunter-gatherers in southern Africa were part of the culture and technology of the inhabitants of this site 44 000 years ago."
Backwell said in a statement on Monday that the team's results had shown without a doubt that, at around 44 000 years ago, the people at Border Cave were using digging sticks weighted with perforated stones, like those traditionally used by the San.
Earliest evidence of use of poison, beeswax
"They adorned themselves with ostrich egg and marine shell beads, and notched bones for notational purposes," said Backwell. "They fashioned fine bone points for use as awls and poisoned arrowheads. One point is decorated with a spiral groove filled with red ochre, which closely parallels similar marks that San make to identify their arrowheads when hunting."
According to the researchers, chemical analysis of residues on a wooden stick decorated with incisions reveals that, like San objects used for the same purpose, it was used to hold and carry a poison-containing ricinoleic acid found in castor beans. This represents the earliest evidence for the use of poison.
A lump of beeswax, mixed with the resin of toxic Euphorbia, and possibly egg, was wrapped in vegetal fibres made from the inner bark of a woody plant.
"This complex compound used for hafting arrowheads or tools, directly dated to 40 000 years ago, is the oldest known evidence of the use of beeswax," said Backwell.
Warthog tusks were shaped into awls and possibly spear heads. The use of small pieces of stone to arm hunting weapons was confirmed by the discovery of resin residue still adhering to some of the tools, which chemical analysis identified as a suberin (waxy substance) produced from the sap of Podocarpus (yellowwood) trees.
The study of stone tools discovered in the same archaeological layers as the organic remains, and from older deposits, showed a gradual evolution in stone tool technology, the researchers found.
Organic artifacts 'appeared relatively abruptly'
"Organic artifacts, unambiguously reminiscent of San material culture, appear relatively abruptly, highlighting an apparent mismatch in rates of cultural change.
"This finding supports the view that what we perceive today as 'modern behaviour' is the result of non-linear trajectories that may be better understood when documented at a regional scale."
The research team, led by Francesco d'Errico, director of research at the French National Research Centre, published its findings in the articles: "Early evidence of San material culture represented by organic artifacts from Border Cave, South Africa".
The team comprised d'Errico, Backwell, Paola Villa, Ilaria Degano, Jeannette Luceiko, Marion Bamford - a palaeobotanist also from the Bernard Price Institute - Thomas Higham, Maria Perla Colombini, and Peter Beaumont.
A second article, "Border Cave and the Beginning of the Later Stone Age in South Africa", was also published on Monday. The authors were Paola Villa, Sylvain Soriano, Tsenka Tsanova, Ilaria Degano, Thomas Higham, Francesco d'Errico, Lucinda Backwell, Jeannette Luceiko, Maria Perla Colombini and Peter Beaumont.