Article summary
Guran, S. H., Yousefi, M., Kafash, A., & Ghasidian, E. (2024). Reconstructing contact and a
potential interbreeding geographical zone between Neanderthals and anatomically modern
humans. Scientific Reports, 14, 20475.
https://doi.org/10.1038/s41598-024-70206-y
Introduction/Background
This article examines the geographic zones where H. Neanderthalensis and anatomically modern
humans (AMHs) may have come into contact approximately 120000-80000 years ago. The genetic
evidence confirms interbreeding between Neanderthals and AMHs, but ecological and geographic
contexts in which it occurred are debated. Identifying where their habitats met is essential for
understanding patterns of migration, interactions of early humans, and gene flow in the Middle
Paleolithic.
Research objective
The researchers aimed to reconstruct the paleogeographic distribution of Neanderthals and early
Homo sapiens during MIS 5 using ecological niche modelling (computation technique used for
prediction of a species’ potential distribution across geographic space and time). Their goal was to
identify regions where environmental conditions would have supported the coexistence of both
species, so that latter contact and interbreeding would be possible.
Methods
The study combined archaeological occurrence data (locations of fossil and cultural remains of each
species) with climatic environmental variables. They used ecological niche modelling and
geographic information systems to predict suitable habitats for each species based on temperature
and precipitation. By modelling the environmental preferences of Neanderthals and AMHs and
projecting these preferences on MIS 5 climate data, the researchers generated maps of potential
species distributions. Overlapping areas between the two models were interpreted as potential
contact zones.
Results
The ecological models revealed significant areas of spatial overlap between Neanderthals and
AMHs distributions during MIS 5. One of the most notable contact zones was found in Zagros
Mountains region of Southwest Asia. Climatic variables played an important role in determining
habitat suitability, suggesting that both Neanderthals and AMHs were constrained by environmental
conditions. The modelling indicated that Southwest Asia served as a “corridor”/“crossroads” where
environmental conditions could support both species at once.
The findings suggest that geographic and climatic factors likely gave opportunities for interactions
between Neanderthals and early modern humans. Thus, rather than random encounters, contact may
have been structured by shared ecological niches in transitional environmental zones. It supports the
idea that Southwest Asia was a key region in Pleistocene human evolution and population
interaction.
Conclusion
This research provides evidence that environmental modelling can help identify plausible contact
zones between Neanderthals and AMHs. By reconstructing population distributions during MIS 5,
the authors propose the Zagros region as a potential area of coexistence and interaction. The study
contributes to understanding Middle Paleolithic population dynamics by including climatic data in
the analysis of possible contact zones of early humans.