Ancient stone 'breadcrumbs' reveal early human migration out of Africa

One of the distinctive stone tools, made with an ancient flint-knapping technology known as Nubian Levallois, found at the archaeological site in the Negev Desert.
One of the distinctive stone tools, made with an ancient flint-knapping technology known as Nubian Levallois, found at the archaeological site in the Negev Desert. (Image credit: Emil Eladjem/Israel Antiquities Authority)

About 130,000 years ago, an early wave of anatomically modern humans — Homo sapiens — left the Horn of Africa and spread north along the center of the Arabian Peninsula, which was wetter and greener than it is now. Their distinctive way of making flint points has been used as a "breadcrumb" trail to mark their progress. Now, scientists may have found the northernmost of these breadcrumbs in Israel's Negev Desert.

Archaeologists from the Israel Antiquities Authority (IAA) report they unearthed the distinctive flints, made with a technique called Nubian Levallois, at an ancient "flint-knapping" site near the city of Dimona, where a photovoltaic solar power plant will be built.The flints, which are thought to date back about 100,000 years, could be further evidence of the spread of Homo sapiens along the central Arabian route from Africa, said IAA archaeologist Maya Oron, who is also studying the Negev as a doctoral student at the Hebrew University of Jerusalem.

Related: Stark beauty: See images of Israel's Negev Desert

The site is rich in raw flint and is clearly where the ancient tools were manufactured, she said; if its age is confirmed, the finds may be a new breadcrumb along the trail of early modern humans into the northern regions of the Levant.

Some pieces of flint made with the same technique have been found in the Negev before, but those were found on the desert surface and their dating is uncertain; this is the first discovery of so many Nubian Levallois flints in a buried and datable archaeological layer, she said.

"We have hundreds of items of flint," Oron told Live Science. "We've mapped them in three coordinates, so that after we do the other work we can see what lay near what."

The finds were unearthed in southern Israel's Negev Desert, at a site being excavated by government archaeologists ahead of the construction of a solar power plant.

The finds were unearthed in southern Israel's Negev Desert, at a site being excavated by government archaeologists ahead of the construction of a solar power plant. (Image credit: Emil Eladjem/Israel Antiquities Authority)

Ancient technology

Nubian Levallois technology is a refinement of an earlier flint technology, now called "classic" Levallois, which is named after the Levallois-Perret suburb of Paris where it was found in the 19th century. 

Both methods allowed people to make several points out of a single lump of flint, by repeatedly knapping it — striking it with a harder stone, so that it fractures in specific ways — while the flake forming the point was still attached. The resulting core had a distinctive curved shape, called a "tortoise." 

Related: Photos: Mysterious human ancestor wielded oldest stone tools

In the Nubian Levallois technique, however, the resulting points were sharper and the core had a distinctive pointed shape, like the beak of a bird. It is named after Nubia, the region on the border of modern Egypt and Sudan where scientists think early modern humans used the technique about 130,000 years ago.

Both early modern humans and Neanderthals are thought to have used the Classic Levallois process. But many researchers think Nubian Levallois required greater planning skills to figure out and greater language skills for it to spread; as such, it could be a hallmark of Homo sapiens.

The site is the northernmost point where Nubian Levallois flint tools have been found in a datable archaeological layer, which is thought to be about 100,000 years old. (Image credit: Emil Eladjem/Israel Antiquities Authority)

Out of Africa

Some early modern humans are known to have first left Africa perhaps up to 270,000 years ago, but the routes they took and just when they took them is fiercely debated by scientists.

In any case, the spread of early modern humans through the center of the Arabian Peninsula about 100,000 years ago — perhaps over a land-bridge where the Bab-el-Mandeb Strait is now located — was probably not the last Homo sapiens migration out of Africa.

This wave is now thought to have died out, while a later Homo sapiens migration left the continent and entered what is now Israel about 60,000 years ago, perhaps along the northern coast of the Sinai Peninsula. It's this later migration of modern humans that is thought to have populated the rest of Asia, Oceania, Europe and the Americas.

The ancient technology used for making Nubian Levallois flints is thought to be a hallmark of early modern humans and could chart their progress from Africa through the Arabian Peninsula. (Image credit: Emil Eladjem/Israel Antiquities Authority)

Meanwhile, there is evidence that some Neanderthals from Europe lived in the region that now includes Israel about 100,000 years ago, Oron said.

"There is a lot of debate about the interaction between these two species in our area, because it happens much earlier than in Europe," she said.

Related: See photos of our closest human ancestor

The new Nubian Levallois flints add a further clue that could help explain the early spread of Homo sapiens in the region, and perhaps reveal more about their interactions with the Neanderthals who also lived there around that time: "It's like a jigsaw puzzle that we don't have all the pieces, but this is another piece in it," she said.

Oron and her colleagues have yet to publish their research in a peer-reviewed journal, but they hope to do so in about a year after they've completed radiocarbon dating of the artifacts.

Rémy Crassard, a prehistorian at the National Scientific Research Centre in France (CNRS) who has researched Nubian Levallois technology in the Arabian Peninsula, is keen to see the scientific publication of the finds. "This new discovery in the Negev could definitely add crucial information to our understanding of human dispersals out of Africa," he said.

Scientists debate the implications of Nubian Levallois flints, he said. 

"We still don't know the origins of this technology, if it has been re-invented through time and space without connections, or if it is a real marker of African dispersals of Homo sapiens," Crassard told Live Science. "More dated sites are needed both in Africa and in Arabia, as well as cautious comparative studies in material culture."

Originally published on Live Science.

Live Science Contributor

Tom Metcalfe is a freelance journalist and regular Live Science contributor who is based in London in the United Kingdom. Tom writes mainly about science, space, archaeology, the Earth and the oceans. He has also written for the BBC, NBC News, National Geographic, Scientific American, Air & Space, and many others.