Stone and water determined human settlement of the desert

In prehistory, whether a desert could be settled depended not only on the availability of water but also on the presence of stone suitable for toolmaking. Researchers from the Czech Republic, Austria, Portugal, the United States and Oman have built a general, openly available model that can predict in which of the world’s desert regions people dependent on stone tools could have lived permanently. Among other data, the research team tested the model against results from a Czech archaeological expedition in Oman. The study, published today in the prestigious journal Nature, changes our understanding of how early humans colonised the planet.

For a long time, models of how early humans spread across deserts rested on a single assumption: where there was water, there were people. During the Pleistocene, monsoon rains transformed the Arabian Peninsula into a landscape of lakes and grassy plains — a “Green Arabia” that opened up corridors for early humans moving out of Africa. The new study shows, however, that a second resource was just as important: stone. Where suitable toolmaking stone was lacking, the desert interior remained empty, even where there was enough water.

Water without stone was a dead end

The team based this finding in part on a 1,300-kilometre expedition crossing of the Rub’ al-Khali desert in Saudi Arabia. The expedition found abundant evidence of ancient freshwater lakes, but across the entire interior not a single stone tool, nor any raw material from which a tool could have been made. The explanation lies in the geology: rocks yielding suitable stone are exposed only at the margins of the desert, and towards its interior they dip beneath a thick cover of sand and salt flats. “We stood on the shore of one ancient lake after another, yet found nothing made by human hands. Water without stone was a dead end,” sums up Rudolf Dellmour of the University of Vienna, the study’s first author.

A universal model that anyone can use

“The initial findings from Saudi Arabia led us to develop a general model that links water availability with the geology of stone raw material and predicts what we call human settlement potential — in other words, where in a given landscape people dependent on stone tools could have lived permanently. Models built on climate and water alone can substantially overestimate how much of the desert prehistoric people were able to inhabit,” says Roman Garba of the Institute of Archaeology, Prague, and the Nuclear Physics Institute of the Czech Academy of Sciences, who contributed to the study.

Crucially, the new model is not tied to Arabia. The authors have released it as an open-source software tool under a free licence. Anyone can feed in geological and hydrological maps of their own region and estimate where prehistoric people could have lived there. The data and code are deposited in the public OSF and Zenodo repositories and are freely available for download. The full study is likewise freely available as open access.

The Czech connection: data from the Oman expedition

Validation of the model was made possible by fieldwork in Oman led by anthropologist Jeffrey Rose of the University of the Algarve in Portugal, who has worked closely with Czech researchers since 2022. “Two decades of research in Oman taught us exactly where good stone is to be found. When we carry that knowledge over into the sand desert, the model predicts an empty interior — and that is precisely what our fieldwork confirmed,” says Jeffrey Rose, the study’s corresponding author. Data from recent field seasons were contributed by the Czech archaeological expedition ARDUQ in Oman, led by Roman Garba. It was these field observations of where raw material occurs and where it is absent that made it possible to test the model against the actual distribution of prehistoric sites.

Fieldwork in Oman (2022–2025) was supported by the Praemium Academiae award of the Czech Academy of Sciences granted to Viktor Černý (Institute of Archaeology of the CAS, Prague). The study also draws on the European Research Council (ERC) grants DISPERSALS and FINISTERRA (University of the Algarve). The crossing of the Rub’ al-Khali was funded by the Adventure Lab Association (Vienna), with logistical support from Nokian Tyres.

Publication

Dellmour, R. W., Coco, E., Samawi, O., Al Kindi, M., Al Mahrooqi, A., Bebber, M. R., Eren, M. I., Harzhauser, M., Garba, R. & Rose, J. I. Stone and water governed early human settlement of the desert. Nature (2026). https://doi.org/10.1038/s41586-026-11180-5

Data and code: OSF (https://osf.io/4mw23/) and Zenodo (https://doi.org/10.5281/zenodo.21758429); data released under a CC-BY 4.0 licence, code under the MIT licence.

Media contact

Ing. Mgr. Roman Garba, Ph.D. · Institute of Archaeology of the CAS, Prague / Nuclear Physics Institute of the CAS · garba@arup.cas.cz · +420 731 114 444

Corresponding author: Jeffrey I. Rose · Universidade do Algarve, Faro, Portugal · jirose@ualg.pt

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