A new discovery of archaeological material at a site in southern Africa 600 km inland from the coast is challenging prior beliefs that the complex behaviors of Homo sapiens started in coastal environments, according to research published Wednesday in Nature.
A team of researchers from eight institutions in five countries — including Australia, South Africa, Canada, Austria and the United Kingdom — led an excavation of Ga-Mohana Hill North Rockshelter in the southern Kalahari Basin, where they found several nonutilitarian items, such as calcite crystals. These crystals are thought by archaeologists to have been collected and brought to the site 105,000 years ago, which provides evidence for complex behaviors. The people who used them in the Kalahari had rich social and spiritual lives, said Jayne Wilkins, a paleoarchaeologist and researcher at Griffith University.
"Items like these are generally associated with the deep roots of symbolism, art and culture," Wilkins said. "I think the crystals at Ga-Mohana were probably collected for some of the same reasons that people collect crystals today — for their beauty and striking visual properties, and perhaps to play a role in ritual activities."
These kinds of nonutilitarian items don't start making an appearance in southern Africa until 100,000 years ago, at around the same time Homo sapiens started making beads and engraving patterns on their objects.
Fragments of ostrich eggshells were also found at the site, which the researchers say may be the remains of containers used to store water.
Although previous studies of ancient Kalahari sites indicated that early humans lived there, none have found evidence for innovative human behaviors during this period.
Despite the important insight excavations of inland southern Africa might give to understanding human origins, the most important new discoveries about the emergence of Homo sapiens have come from the coast. As a result, some hypothesized that it was coastal adaptations that led to complex behaviors we see in modern humans.
"I wondered if the differences between the coastal and interior archaeological records were due more to research bias than reality, and I was inspired by my supervisors and mentors to go look for new sites that could shed light on early Homo sapiens origins in the Kalahari," Wilkins said.
Before this excavation of Ga-Mohana Hill, the team searched another rock shelter on the other side of the hill but found no Middle Stone Age archaeology. This was the first time the site had been fully investigated, according to Wilkins; archaeologists in the early 1980s had done a test search but concluded that the sediments were too mixed up to find useful information.
This most recent excavation not only found intact deposits but was also able to demonstrate that the artifacts they found had not been previously disturbed.
The modern Kalahari desert is a dry environment that would be difficult for early humans to survive in, but it's possible that at the time these Homo sapiens were collecting their crystals, it was a much wetter environment with abundant resources. Wilkins and her colleagues found deposits that are indicative of "past shallow pools and flowing surface waters."
There are many regions across the African continent, particularly in arid regions like Kalahari, and in West and Central Africa, that haven't been sufficiently investigated by archaeologists, according to Wilkins, but discoveries like this are shifting perceptions about viable excavation sites. This team of researchers is currently expanding excavations at Ga-Mohana Hill North Rockshelter to see what other time periods are represented there, as well as excavating other new sites in the southern Kalahari.
"The origin of our species was more complicated than we tend to think. There was no single magical moment in one place where, voila, now humans are smart and creative, and they can spread and take over the rest of Africa and the world," Wilkins said. "The more archaeological research we do in Africa, the more we can see that the emergence of Homo sapiens was a complex process."
The study "Innovative Homo sapiens behaviours at 105,000 years ago in a wetter Kalahari," published March 31 in Nature, was authored by Jayne Wilkins, Griffith University and University of Cape Town; Benjamin J. Schoville, University of Cape Town and University of Queensland; Robyn Pickering, Kyle S. Brown, Jessica von der Meden and Wendy Khumalo, University of Cape Town; Luke Gliganic and Michael C. Meyer, University of Innsbruck; Benjamin Collins, University of Cape Town and University of Manitoba; Sechaba Maape, University of the Witwatersrand; Alexander F. Blackwood, University of Cape Town and La Trobe University; and Amy Hatton, University of Cape Town and University College London.
This story has been updated to clarify which artifacts researchers defined as nonutilitarian.