At a collapsed limestone cave on the Mediterranean coast of southern Turkiye, nearly 20,000 stone artifacts tell a remarkable story of continuity. Layer after layer, across a 30,000-year span that covers both Neanderthal and Homo sapiens occupations, the technology stays the same. The raw materials are the same. Even the seashells they chose to collect are the same.
The findings, published July 6 in PNAS by an international team led by Ismail Baykara (Gaziantep University) and Naoki Morimoto (Kyoto University), provide the strongest evidence yet that the two human species did not merely coexist in the Levant, they may have actively shared cultural traditions.
The site and the sequence
Ucagizli II Cave is located in Hatay Province, just a few kilometers north of the Turkiye-Syria border, on a wave-cut limestone platform 11 meters above sea level. The site was discovered in the 1980s but systematic excavations began only in 2020. Its older, better-known neighbor, Ucagizli I, preserves an Early Upper Paleolithic Homo sapiens occupation. Ucagizli II preserves both.
The lower layers, dated to 77,000 to 59,000 years ago, contain the remains of Neanderthal occupations: Levallois Mousterian stone tools, terrestrial game remains, and marine mollusks. The upper layers, dated to 59,000 to 47,000 years ago, contain the same, but left by Homo sapiens.
“We cannot definitively prove a temporal or physical overlap between the two hominin species at the site itself,” Morimoto told New Scientist. “However, this is indeed a central hypothesis that we are exploring.”
The shell that tells the story
The most striking evidence for shared culture comes not from stone tools, which could reflect similar functional constraints, but from seashells. Across both occupation layers, the researchers found nearly 30 specimens of Columbella rustica, a small marine gastropod known as the rustic dove shell. The shells had virtually no food value; they were collected, some with holes or broken tips suggesting they were strung as beads or pendants, purely for their appearance.
This specific shell preference is not coincidental. The team found that both Neanderthals and Homo sapiens at Ucagizli II overwhelmingly selected Columbella rustica over the many other shell species available on the nearby Mediterranean shore. “This strong preference suggests that both human groups shared a common cultural evaluation of this specific shell, finding it uniquely valuable or attractive,” Morimoto said.
Similar shell ornament use by Neanderthals has been documented in Iberia, where shells with pigment traces date to approximately 115,000 years ago, and at Vlakno Cave in Croatia. But the Ucagizli II evidence is unique in showing the same preference across the species boundary at a single site.
Cultural exchange, not independent invention
The researchers argue that the consistency in both tool technology and symbolic shell use is difficult to explain by independent parallel development alone. Instead, they propose a model of regional contact: populations of Neanderthals and Homo sapiens occupying overlapping territories in the Levant, observing each other, and transmitting cultural practices, even if they did not share the same cave at the same time.
“Given that daily survival and food procurement were literally matters of life or death, their shared focus on a non-utilitarian seashell is highly revealing,” Morimoto told Discover Magazine. “It demonstrates that even under intense survival pressures, both human groups placed a high value on potentially symbolic behaviors.”
External experts are taking the argument seriously. “They must have been aware of one another regularly,” said John Gowlett of the University of Liverpool. “This paper helps show that this did not need to mean separate material cultures or even hunting patterns.” Chris Stringer of the Natural History Museum in London noted that older Levant sites already show evidence of cultural sharing between the two species.
Caveats
The researchers are careful to note that the evidence does not prove direct cohabitation at Ucagizli II. The Neanderthal occupation ended before the Homo sapiens occupation began at this specific cave. The cultural exchange model is the most plausible explanation, but convergent evolution, both species independently arriving at similar solutions, cannot be fully ruled out. “This is a central hypothesis that we are exploring,” Morimoto said, “not a definitive conclusion.”
Sources
- Baykara, I., et al. “Long-term cultural continuity across the Neanderthal–modern human sequence at Ucagizli II Cave, northern Levant.” PNAS (July 6, 2026). DOI: 10.1073/pnas.2609061123. https://doi.org/10.1073/pnas.2609061123
- Woodford, J. “Artefacts hint at cultural exchange between Neanderthals and humans.” New Scientist (July 6, 2026). https://www.newscientist.com/article/2533108-artefacts-hint-at-cultural-exchange-between-neanderthals-and-humans/
- Phys.org: “Cave findings reveal modern humans, Neanderthals may have shared long-term cultural continuity” (July 2026). https://phys.org/news/2026-07-cave-reveal-modern-humans-neanderthals.html