Signs of Stone Age arms race
A DRAMATIC change in the weather thousands of years ago created a hunters’ paradise in the southern Cape that led to a Stone Age weapons race.
Scientists working in the Pinnacle Point cave complex outside Mossel Bay have long been puzzled by the large number of Stone Age hunting tools, such as miniature spear tips, that appeared in the area 70 000 years ago — long before they appeared anywhere else in the world.
New research findings show that the upsurge in Stone Age weapons coincided with a sudden shift in rainfall patterns in the southern Cape and a fall in sea levels, which created a grassy plain filled with animals stretching at times about 90km beyond the coastline today.
Researchers believe that perfect hunting conditions led to the production of small but deadly weapons, called microlithic tools, which have been unearthed in caves where our early ancestors lived.
“Microlithic technology appears in South Africa around 71 000 years ago, but worldwide you don’t see that. Usually these tools only appear about 20 000 years ago,” Professor Curtis Marean told the Sunday Times during a visit to the Pinnacle Point site last month. “People shifted to microlithic technology when more summer rains came to the south coast. At the same time, the sea level dropped and a huge coastal plain opened up. Where most South Africans look out and see the sea, there would have been a huge grassy plain.”
Evidence of changing rainfall and vegetation patterns was found in several stalagmites — the deposits found on cave floors caused by water dripping from the ceiling. By analysing these deposits, scientists were able to tell what kind of vegetation was growing
Researchers believe that perfect hunting conditions led to the production of small but deadly weapons
above the cave.
The analysis of fossil cave deposits showed that, when summer rains increased and the coastal plain developed, the area teemed with grassland animals such as hartebeest and wildebeest, which are not normally found in the Cape. The climate and the abundant supply of food combined to create optimal conditions for human development, researchers believe.
Working with stalagmites and stalactites — collectively known as speleothems — involved some unusual precautions, said Marean. Each sample had to be carefully wrapped in duct tape and medical fibreglass to protect against cracking and were then removed using a diamond-tipped saw or angle grinder. The samples were then analysed in a lab.
Guy Midgley, South African National Biodiversity Institute director of climate change and bioadaptation, said the Pinnacle Point research showed that man’s early ancestors had adapted to climate change. Present-day societies were not as adaptive, however, and were therefore more at risk.
“Agrarian societies that have become sedentary and very populous lack the capacity to adapt to climate change that was possessed by the low populations of mobile hunter-gatherer societies of old,” said Midgley.
The latest Pinnacle Point research follows earlier findings that show Southern Africa to be the birthplace of modern humans. Researchers believe that the area’s rich marine environment, with its abundance of healthy food full of omega oils, was another reason humans evolved here.
Fossil evidence of Homo sapiens has been found across Africa, including two 195 000-year-old skulls in Ethiopia. But the Mossel Bay site has consistently thrown up the oldest known evidence of modern human behaviour, resulting in its widespread recognition as the cradle of modern civilisation.
In a previous interview with the Sunday Times, Marean said the Cape had a strong claim to be the primary birthplace of modern humans. “Those other areas [in Africa] don’t have the same evidence for behavioural complexity. What we’re talking about here is the origins of modern humans — the modern behaviour of people like us who have language, who view the world through symbols, who express themselves artistically. That’s where the Cape is very rich,” he said.
The Pinnacle Point caves were declared a provincial heritage site in January, the first step towards having them declared a world heritage site.