The first archeologists to find strange stone artifacts on Naxos were French researchers working on the Greek island in 1981. Naxos, the largest in a cluster known as the Cyclades that dot the Aegean Sea, is rich in the type of archeology many would recognize from classical exhibits in museums: 5,000-year-old, beautifully proportioned white marble figurines; 3,000-year-old, strikingly patterned pottery vessels.
These scrappy pieces of rock looked much, much older.
“The stone tools they were finding on the site looked nothing like the stone tools that had ever been found before on prehistoric sites in the Cycladic Islands,” said Tristan Carter, an archeologist at McMaster University in Hamilton.
Archeologists have long believed that the first people to colonize the region were early farmers who arrived by boat approximately 9,000 years ago. Only humans who had made the leap from a hunter-gatherer subsistence to organized agriculture — a major revolution in the history of our species, one that saw a lurch forward in technological and social complexity — could have accomplished the sea crossing.
But the stone tools on Naxos appeared to be hewn by Paleolithic people — much more ancient humans, perhaps not members of our species at all. Since 2013, Carter has co-directed a new round of investigations on Naxos. He and a handful of others working in the region have begun to furnish evidence that humans reached the islands of the Aegean Sea 250,000 years ago and maybe earlier. If those dates are confirmed, it means the first people there were Neanderthals, their probable ancestors, Homo heidelbergensis or maybe even Homo erectus.
Could these archaic hominins have travelled by boat?
Sea voyaging is supposed to be an indicator of “behavioural modernity,” the suite of capabilities that distinguishes us from our primitive, now-extinct human cousins and from primates. A crossing of any major distance requires the tool-making and co-operation necessary to build a craft, the navigational savvy to pilot it and, perhaps most significantly, the imagination and daring to conceive of the journey in the first place.
Other researchers insist that much better evidence needs to be discovered to attribute such complex behaviours to Neanderthals and other hominins: a rewriting of a significant chapter in the evolution of our genus.
“If things like erectus were deliberately zooming around bodies of water 1.5 million years ago, that would be an absolutely massive deal for overturning our received understanding for how these creatures think and behave,” said Tom Leppard, Renfrew fellow in archeology at the University of Cambridge, and a cautious voice in the debate.
In recent years, many of these behavioural firewalls have crumbled. Archeologists have found indications, some still disputed, that Neanderthals carved cave symbols, painted their bodies with pigment, created musical instruments and jewelry, and intentionally buried their dead — all practices thought to be exclusive to us. Most stunningly, scientists have shown that living people with European or Asian ancestry carry a small amount of Neanderthal DNA, evidence of prehistoric interbreeding.
“Research over the last couple decades has just perpetually shown us that all of these characters are more capable, more complex that we thought,” Carter said. “It’s all about the archeology of ego in us.”
Still, he is the first to say that with the stakes so high, his team must be incredibly careful in how they work and what they claim: “There’s going to be a very high bar for us.”
The French team on Naxos was not the first working on Aegean and Mediterranean islands to report artifacts older than the Neolithic, as the era that began with the adoption of agriculture is known. But the older discoveries were piecemeal and never stood up to scrutiny.
Two years ago, Carter and project co-director Demetris Athanassoulis obtained permission to excavate the formerly French site on Naxos, known as Stelida.
“I had always had a sneaking feeling, having visited Stelida a few times during my PhD many moons ago, that maybe this site fit into these new discoveries.”
The site is challenging. The researchers believe it was a quarry, where people came to retrieve the material to make stone tools for hundreds of thousands of years.
“It’s like going to a factory and only seeing the stuff they threw out,” Carter said.
After years of work, Carter’s team has found loads of artifacts, including distinctive tool types that on mainland Greece have been exclusively associated with Neanderthals and Homo heidelbergensis and could be more than 250,000 years old. But that won’t be enough to convince the skeptics: they need artifacts buried in clearly defined layers of soil that can be accurately dated.
“A lot of people are going, “Aha! You have proven you have Neanderthal seafarers,’” Carter said. “We’ve always said, first of all, we’ve got to wait until we’ve got really, really good scientific dates.”
Carter is relying on a method known as optically stimulated luminescence. Unlike radiocarbon dating, optically stimulated luminescence works on extremely old soil deposits, but takes months to process. Early lab results have dated some of the Stelida artifacts to at least 50,000 years ago. But the team is still waiting for results from the lower layers of the site, where the pre-Neanderthal-looking tools were found.
Solid dates are important to estimate sea levels. Unlike Crete and Cyprus, (where excavating has taken place) Naxos is not a “true” island: when sea levels fell, it was connected to its neighbours to form one mega-Cycladic island. The region’s active tectonics don’t help: modellers disagree on whether that Cycladic land mass was connected to the mainland at times, allowing hominins to reach what is now Naxos by foot.
Because most working in the region are specialists in the cultures that produced those exquisite ivory figures and pottery, “a lot of the archeologists really weren’t trained to look for scatters of broken rocks, basically, because it wasn’t very exciting,” Alan Simmons said.
The artifacts may not look very exciting, but the implications are. If archaic hominins could reach the Aegean islands by boat, where else might we find them?
“We’ve always looked at the sea as a barrier,” Simmons said. “But what some people are arguing is maybe it wasn’t a barrier — maybe it was a highway.”