KEY POINTS:
For early humans, one of the first displays of modern behaviour was a sort of beach party and clam bake along the coast of South Africa.
Artifacts found in a cave on coastal cliffs overlooking the Indian Ocean showed that these people 164,000 years ago cooked mussels and other shellfish, used red pigment perhaps as body paint and made small stone blades that could be used at the tip of a spear - all far earlier than previously thought.
An international team of scientists, writing in the journal Nature, described the earliest evidence for humans living in a coastal habitat and exploiting the resources of the sea.
"We do not have human fossils from this site, but they were very likely modern humans indigenous to South Africa," Arizona State University anthropologist Curtis Marean, who led the study, said by email, noting our species, Homo sapiens, likely emerged between 200,000 and 150,000 years ago in Africa.
The world was in a glacial period from 195,000 to 125,000 years ago, with much of Africa in cold and dry conditions that may have prompted early humans to find new food sources and expand from inland to coastal habitats, the researchers said.
Marean said that the findings support the idea that on the far southern shore of Africa a small population of modern humans endured this glacial period by expanding their diet to include shellfish, harnessing new technologies, and by using symbolism in their social relations.
It may be that this was "the progenitor population" for all modern people, Marean said. Habitation of coastlines is of great interest to scientists wondering about the later spread of modern humans out of Africa.
The earliest previous evidence for people using marine resources and coastal habitats was from 125,000 years ago, the researchers said.
Writing a commentary accompanying the research, Sally McBrearty of the University of Connecticut and Chris Stringer of the Natural History Museum in London said these findings "provide strong evidence that early humans displayed key elements of modern behaviour" 164,000 years ago.
The Pinnacle Point cave site, on the south coast of South Africa, is located near Mossel Bay.
The scientists said they found shellfish, including brown mussels, at the site. The presence of a type of barnacle that grows on the skin of whales indicated these people also may have scavenged whales corpses that washed ashore, they said.
And they found pieces of pigments, particularly red ochre, probably used for decorating objects and painting their bodies, strongly suggesting the use of symbolic displays, Marean said.
"In our society, the analogy is putting on make-up, jewellery and fancy watches to indicate, or fool others, about our status and wealth," Marean added.
The researchers said this is the earliest known evidence for pigment use. And symbolic behaviour indicates that these people may have used some sort of language, they added.
The previous earliest evidence for tools like the small, thin stone blades found at the site dates to 70,000 years ago, the researchers said.
Shellfish were among the last additions to the human diet before the debut of domesticated plants and animals, Marean said. Early hunter-gatherer relatives of modern humans for millions of years dined on only land plants and animals, the scientists said.
"It is likely that shellfish was a critical food resource for the survival of this population during this long dry time period, when terrestrial food resources were likely less productive," Marean said.
- REUTERS