Archaeologists excavating an ancient river bed in Israel have uncovered a vast prehistoric site where, half a million years ago, early humans created a hoard of elaborate flint tools that suggest their cognitive abilities were much closer to our own than previously thought.

Hundreds of thousands of artifacts have emerged since archeologists first stumbled upon the site last year while surveying an area slated a new neighborhood in the nearby Arab-Israeli town of Jaljulia.

Given that Israel is littered with archaeological remains from the dawn of man onwards, all new construction sites are explored by experts before building can begin.

“Usually in these surveys, you dig down a meter or two and go home,” says Lena Brailovsky, the Israel Antiquities Authority archaeologist who discovered the site. “But we knew that in open fields that are close to a river, we could expect to find prehistoric sites. We knew there was something here and we didn’t give up.”

A perfect spot for humans

Open gallery view A view of a half-a-million-year-old open-air prehistoric site found in Jaljulia, during a salvage excavation Credit: Ariel David

Brailovsky bulldozed her way to a depth of more than five meters until hitting paydirt: layer upon layer of tools and animal bones littering the open-air site.

Open gallery view Tel Aviv University archaeologist Ran Barkai shows a sections of sediments filled with pieces of flint and tools at a prehistoric site in Jaljulia. Credit: Ariel David

Since that discovery, in November 2016, the IAA and Tel Aviv University have been conducting a massive salvage excavation in a mad dash to learn as much possible from the site before construction work is greenlighted. Mounds of sediments have been removed over an area of about a hectare, uncovering at least six distinct sub-sites along the once-marshy banks of a stream that flowed through what is today the West Bank and central Israel.

“It was a perfect spot for humans,” says Ran Barkai, an archaeologist from Tel Aviv University. “The water brought flint nodules from the hills, which were used to make tools on the spot, and it attracted animals, which were hunted and butchered here. They had everything that prehistoric people needed.”

The dig may have only scratched the surface. There may be many more such “prehistoric mega-sites” around the Qana, now a seasonal stream that lies to the south of Jaljulia, Barkai says.

“Over time, the water changed course and the people moved with it. That’s why there are so many different sites,” Barkai told Haaretz during a recent visit. “It was like a prehistoric picnic spot, which people would return to over and over again.”

Homo erectus, inventor of the 'Swiss army knife'?

Based on the tools found at the site and early tests on the paleomagnetism of the sediments, the site has been tentatively dated to around half a million years ago, and attributed to Homo erectus, the species of hominid most likely to have that inhabited the area at the time.

Open gallery view Lena Brailovsky, an archaeologist with the Israel Antiquities Authority, displays some of the flint tools found in the prehistoric site at Jaljulia Credit: Ariel David

Open gallery view Hundreds of hand axes were uncovered in the excavation by Jaljulya, demonstrating technique that begs the question: Did man begin to develop much earlier than thought? Credit: Samuel Magal, Courtesy of the Israel Antiquities Authority

Erectus was most probably our direct ancestor, and is believed to have been the first hominid to leave Africa around 1.8 million years ago and spread through Eurasia. Firmer proof of the timing of the Jaljulia site awaits the results of dating tests for the layers of human habitation using optically stimulated luminescence, a method that can tell how long quartz grains have been out of sunlight (i.e., when they were buried).

Many of the artifacts found in Jaljulia are typical bifacial handaxes – Barkai jokingly calls them the “Swiss army knife of the Paleolithic” – which were all-purpose tools produced for more than a million years around the prehistoric world, with minimal changes.

But here’s the rub: mixed in amongst the multitude of handaxes, archaeologists also found flint tools produced using an early form of a different, much more complex technique.

This method, known as the Levallois technique, requires much more work and advanced planning, Barkai says.

Open gallery view Handaxes found at the prehistoric site in Jaljulia: these were much easier to make than the more complex Levallois tools Credit: Ariel David

The Levallois mystery

traditional handaxes were made by slowly hammering a piece of flint into a desired shape, Levallois tools were produced in two stages. First, the flint core was carefully knapped into a specific shape. Then, with one decisive stroke, the knapper would detach a flake that already had the form and size of the desired tool.

“It requires a conceptual leap that allows you to envision the desired tool in the flint core before you even start shaping it,” Barkai says.

This technique yields longer and thinner flakes, and may have been developed because hominids were starting to attach tools to wooden shafts, rather than just bludgeon away at things with their handheld axes, the archeologist speculates.

The Levallois technique was long thought to have been developed among more advanced hominids, Neanderthal and Homo sapiens, and to be the result of a decisive leap forward in our biological and technological evolution.

But Jaljulia – as well as the recent discovery of similar sites in Asia, Europe and Africa – is too ancient to be attributed to anatomically modern humans, Barkai says.

“There is a big discussion on the Levallois technique, when it was invented and whether there is a connection between physical evolution and technological evolution,” he says.

Such discoveries are likely to fuel the debate on questions that lie at the heart of prehistoric research: When did we stop being monkeys and become humans? What is it that makes us human, and how did we gain those nearly-ineffable qualities? And barring divine intervention (or a big black monolith), did this happen thanks to biological evolution or cultural development?

Open gallery view A flint core from which flakes have been detached half a million years ago using the Levallois technique, to archaeologists' surprise. Credit: Ariel David

Already in 2014, research published in the journal Science focused on a mix of handaxes and Levallois tools found in a gorge in Armenia that dated to more than 300,000 years ago. The study concluded that this co-occurrence of tools suggests the more advanced technique was not suddenly introduced by the arrival from Africa of a new, smarter hominid, but evolved locally out of previous methods.

If the dating of the Jaljulia site is confirmed, it would move the clock further backwards on a key technological milestones in our evolution – and one that most probably we Homo sapiens cannot claim as our own.

The advanced cognitive abilities required to make those tools would even predate the controlled use of fire, meaning fire that the hominins ignited themselves, as opposed to helping themselves to brushfire ignited by lightning. According to Barkai, there may be some evidence of sporadic use of fire at Jaljulia, but the earliest evidence of a sustained and controlled blaze was found at Qesem cave, less than 10 kilometers away – but dated to 100,000 years later. (Some archaeologists believe control of fire was achieved in Gesher Benot Yaakov, in northern Israel, as much as 800,000 years ago.)

Maayan Shemer, the IAA archaeologist leading the dig, says the team will work with city planners to strategically locate public gardens and other open spaces over the most promising areas, in hopes that one day researchers will be able to return to Jaljulia to renew their explorations.

Archaeologists closed the dig in December. The site is expected to be covered so that construction on the new neighborhood can begin. “On one hand, it’s sad to bury such an important find, on the other, if they hadn’t planned a new neighborhood, we might have never have known it was here,” Barkai says.