Genetic and archaeological evidence imply a second major movement of Neanderthals from Western to Central and Eastern Eurasia sometime in the Late Pleistocene. The genetic data suggest a date between 120,000 and 80,000 years ago for the dispersal and the archaeological record provides an earliest date of arrival in the Altai by 60,000 years ago. Because the number of archaeological sites linking the two regions is very small, the exact route taken and its timing have been the matter of considerable debate. According to new research, Neanderthals likely used river valleys as natural highways and traveled during warmer periods to move approximately 3,250 km (2,000 miles) through the Urals and southern Siberia in less than 2,000 years.
E. Coco & R. Iovita suggest that Neanderthals could have quickly dispersed from the Caucasus Mountains to the Altai Mountains via a northern route during MIS 3 and MIS 5e. Image credit: Abel Grau, CSIC Communication.
“Our findings show that, despite obstacles like mountains and large rivers, Neanderthals could have crossed northern Eurasia surprisingly quickly,” said Dr. Emily Coco, who began the study as a doctoral student at New York University and is now a postdoctoral researcher at the University of Algarve.
“These findings provide important insights into the paths of ancient migrations that cannot currently be studied from the archaeological record and reveal how computer simulations can help uncover new clues about ancient migrations that shaped human history.”
In building their simulation of Neanderthals’ two-millennia journey, Dr. Coco and her colleague, New York University’s Dr. Radu Iovita, considered the elevation of the terrain, reconstructed ancient rivers, glacial barriers, and temperature to model movement decisions of individuals — an approach similar to that used to model both modern human and animal movement, but not previously applied to Neanderthals.
The researchers found possible migration routes in two ancient periods — Marine Isotope Stage 5e (MIS 5e, beginning approximately 125,000 years ago) and Marine Isotope Stage 3 (MIS 3, beginning approximately 60,000 years ago) — marked by warmer temperatures and therefore more suitable for movement.
Computer simulations indicated that Neanderthals could have reached Eurasia’s Siberian Altai Mountains within 2,000 years during either MIS 5e or MIS 3 using multiple possible routes that all follow the same basic northern path through the Ural Mountains and southern Siberia, often intersecting with known archaeological sites from the same time periods.
According to the authors, the study sheds light on Neanderthal interactions with other ancient human groups.
Specifically, their routes would have taken them into areas already occupied by Denisovans — consistent with existing evidence of interbreeding between the two species.
“Neanderthals could have migrated thousands of kilometers from the Caucasus Mountains to Siberia in just 2,000 years by following river corridors,” Dr. Iovita said.
“Others have speculated on the possibility of this kind of fast, long-distance migration based on genetic data, but this has been difficult to substantiate due to limited archaeological evidence in the region.”
“Based on detailed computer simulations, it appears this migration was a near-inevitable outcome of landscape conditions during past warm climatic periods.”
The findings were published online in the journal PLoS ONE.
_____
E. Coco & R. Iovita. 2025. Agent-based simulations reveal the possibility of multiple rapid northern routes for the second Neanderthal dispersal from Western to Eastern Eurasia. PLoS One 20 (6): e0325693; doi: 10.1371/journal.pone.0325693
