Two species of humans occupied the same small cave in southern Türkiye across a span of roughly 20,000 years, and the stone tools and shell beads they left behind look strikingly alike. Neanderthals lived at Üçağızlı II Cave from approximately 77,000 to 59,000 years ago, and Homo sapiens moved in from about 59,000 to 47,000 years ago, according to a new study published in the Proceedings of the National Academy of Sciences. The overlap in material culture across that transition raises a pointed question: did one group learn from the other, or did two separate populations independently arrive at the same solutions?
Why the Üçağızlı II sequence changes the replacement debate
For decades, the dominant model of human evolution treated Neanderthals and modern humans as fundamentally separate lineages with distinct technologies and behaviors. When Homo sapiens expanded out of Africa, the story went, they replaced Neanderthals through superior cognition or more efficient tools. The record at Üçağızlı II complicates that narrative. The PNAS study on the cave documents the same stone-tool reduction strategies and the same types of pierced shell beads in layers attributed to both species. That continuity stretches across the boundary at roughly 59,000 years ago, when Neanderthal fossils give way to Homo sapiens remains in the stratigraphy.
If these shared traditions reflect direct cultural transmission, the implications are significant. It would mean Neanderthals and modern humans were not just coexisting in the same region but actively exchanging knowledge about how to shape stone and which shells to collect, pierce, and wear. The alternative explanation, independent invention, is harder to sustain when the same specific techniques appear in the same cave, in sequential layers, with no apparent break in the archaeological record.
One way to test the transmission hypothesis would be to compare micro-residue and use-wear signatures on tools from the transitional layers. If late Neanderthal and early sapiens toolkits show statistically higher similarity to each other than either shows to earlier or later layers at the same site, that would strengthen the case for learned behavior passing between the two groups. No such analysis has been published for Üçağızlı II, but the stratigraphic setup makes it an ideal candidate for future work that combines microscopic use-wear, refitting studies, and experimental replication of the knapping sequences.
Another line of evidence could come from high-resolution dating. At present, the transition is bracketed within several thousand years. Narrowing those ranges with additional radiometric samples or alternative chronometric techniques would clarify whether the change from Neanderthals to Homo sapiens was abrupt or gradual. A rapid handover with continuous tool traditions would strengthen the case for direct contact; a long gap between occupations would instead point toward cultural convergence after an interval of abandonment.
Grotte Mandrin and the pattern of shared caves
Üçağızlı II is not the only site where Neanderthals and Homo sapiens appear to have used the same shelter. At Grotte Mandrin in southeastern France, researchers documented an early modern human incursion into Neanderthal territory around 54,000 years ago. The Mandrin sequence shows alternating occupations, with Neanderthal and Homo sapiens layers stacked in rapid succession, suggesting the two groups swapped control of the cave within centuries or less.
The Mandrin case differs from Üçağızlı II in an important respect. At Mandrin, the tool industries associated with each species are distinct. The modern humans brought a different flaking technology, and when Neanderthals returned, they resumed their own methods. That pattern points to replacement or displacement rather than cultural exchange. At Üçağızlı II, by contrast, the continuity in reduction sequences and bead types across the species boundary is exactly what makes the site unusual. The same cave, the same tools, the same ornaments, but different makers.
Taken together, the two sites sketch a more complex picture of contact between the species than either could alone. Mandrin shows that brief encounters happened and that the groups sometimes maintained separate traditions. Üçağızlı II suggests that longer coexistence in the same place could produce shared material culture. The stratigraphic work from Mandrin also confirms that modern humans were present in Neanderthal-dominated regions thousands of years before the final disappearance of Neanderthals, which means the window for cultural contact was wider than older models assumed.
These shared caves also force archaeologists to grapple with the social dynamics of replacement. If Neanderthals and Homo sapiens alternated in the same shelters, they likely knew of each other’s presence, even if they did not always meet face to face. Abandoned hearths, discarded tools, and lingering smoke would have signaled that another population was nearby. Whether those encounters led to conflict, avoidance, or occasional cooperation remains an open question, but the archaeological sequences show that the frontier between the species was porous rather than sharply drawn.
Gaps in the fossil and genetic record at Üçağızlı II
Several pieces of evidence that could settle the transmission question are missing. No ancient DNA or proteomic data from the human fossils at Üçağızlı II have been published. Without genetic confirmation, species identifications rely on skeletal morphology, which can be ambiguous for fragmentary remains. The possibility that some individuals in the transitional layers were hybrids, carrying both Neanderthal and sapiens ancestry, cannot be ruled out or confirmed.
The shell beads cited as evidence of cultural continuity also lack full quantitative documentation in publicly available datasets. The PNAS paper describes the bead types and their distribution across layers in narrative form, but raw counts, sourcing data for the shells, and detailed photographs of the artifacts have not been released beyond the study’s summary tables. Independent researchers attempting to replicate or challenge the continuity claim will need access to those materials, along with standardized criteria for classifying bead types and assessing wear.
Stratigraphic resolution presents another challenge. The transition at 59,000 years ago is defined by the dating of sediment layers and associated materials, but even small disturbances can blur the boundary between occupations. Bioturbation, erosion, and later human activity can move artifacts up or down by several centimeters, potentially mixing Neanderthal and Homo sapiens materials. The Üçağızlı II team reports careful excavation and clear layering, yet only continued micromorphological analysis and independent re-examination of the profiles can fully exclude post-depositional mixing as an alternative explanation for the apparent continuity.
Finally, the broader regional context remains incomplete. Üçağızlı II currently stands out because it preserves a long sequence with overlapping technologies, but other caves along the eastern Mediterranean coast have not been excavated or dated with comparable precision. If future work uncovers similar patterns of shared tool types and ornaments at neighboring sites, the case for widespread cultural transmission between Neanderthals and modern humans will grow stronger. If, instead, Üçağızlı II proves to be an outlier, researchers will need to explain why this particular cave became a focal point for convergent traditions.
For now, Üçağızlı II and Grotte Mandrin together mark a shift in how archaeologists think about the end of the Neanderthals. Rather than a simple story of replacement driven by a single superior technology, the emerging picture is one of overlapping populations, intermittent contact, and at least occasional sharing of ideas. Whether the stone tools and shell beads in a Turkish cave represent direct teaching across species lines or parallel innovations in a shared landscape, they underscore that the last Neanderthals and the first modern humans in Eurasia were not separated by an unbridgeable cultural gulf. They walked the same floors, looked out from the same cave mouths, and, at times, left behind the same kinds of things.
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*This article was researched with the help of AI, with human editors creating the final content.
