For decades, anthropologists envisioned early Homo sapiens as creatures of the savanna—roaming the open landscapes of East Africa, honing their survival skills in vast, dry grasslands. But what if that story is incomplete? What if, in the dense, humid embrace of a rainforest, some of our earliest ancestors were not merely surviving, but thriving?
A new study published in Nature unveils compelling evidence that humans occupied West Africa’s rainforests as early as 150,000 years ago, shattering the conventional notion that tropical forests were inhospitable barriers to early human expansion. This discovery, led by Eslem Ben Arous and a team of international researchers, forces a reconsideration of how Homo sapiens adapted to diverse ecological challenges across the continent.
The key to this revelation lies in Côte d’Ivoire, at a site called Bété I. Long before modern highways and cities marked the landscape, this region was a lush rainforest teeming with life. Excavations at Bété I uncovered a striking connection between early humans and a wet tropical forest environment, dated to approximately 150,000 years ago using advanced dating techniques such as optically stimulated luminescence (OSL) and electron spin resonance (ESR).
Unlike many other early human sites in Africa, which are found in arid or mixed environments, Bété I presents a rare glimpse into an ecosystem where early humans adapted to an entirely different set of challenges. Researchers analyzed plant wax biomarkers, stable isotopes, phytoliths, and pollen to reconstruct the ancient climate. Their conclusion? This was no seasonal woodland—this was a dense, evergreen rainforest, the kind traditionally thought to be too resource-scarce for early human occupation.
“The secure attribution of stone tool assemblages with the wet forest environment demonstrates that Africa’s forests were not a major ecological barrier for H. sapiens as early as around 150,000 years ago,” the researchers state.
In other words, our ancestors were more adaptable than we ever imagined.
Why is this discovery so groundbreaking? For years, scientists debated whether early humans could have sustained themselves in dense forests. Unlike the wide-open savannas, where hunting and foraging strategies were clear-cut, rainforests present a different set of obstacles—poor visibility, fewer large prey animals, and challenging foraging conditions. Yet, the evidence from Bété I suggests that early Homo sapiens found ways to thrive in this environment.
The tools found at the site, many exhibiting Middle Stone Age characteristics, indicate a sustained presence rather than a fleeting exploration. Heavy tools like picks, found in the deeper layers, suggest people were actively modifying their environment, possibly cutting through thick vegetation or digging for tubers.
This aligns with recent findings from other parts of Africa that suggest early human populations were not just surviving in different biomes—they were adapting, innovating, and even specializing.
“These are people who had the time to adjust to their living conditions,” notes co-author Eleanor Scerri.
The idea that Homo sapiens were limited to certain “cradles of evolution” is quickly crumbling. Instead, a more fluid, interconnected story is emerging—one in which human populations moved, mixed, and flourished in a variety of landscapes, long before the major migrations that eventually led to our species’ global dominance.
The persistence of rainforest environments in Côte d’Ivoire throughout various climatic shifts suggests another fascinating possibility: this region may have acted as a refuge during periods of severe aridity in Africa. During ice ages, when much of the continent’s landscapes turned dry and inhospitable, forests like the one at Bété I may have served as a sanctuary for human populations.
“Several independent lines of evidence have confirmed the association between humans and tropical wet broadleaf forest at Anyama, starting at least 150 ka,” the study notes.
This adds weight to the “refugium hypothesis”—the idea that during harsh climate shifts, small pockets of habitable environments preserved human populations and facilitated their eventual expansion.
Unfortunately, the researchers also highlight a growing concern: the destruction of archaeological sites due to modern development. Quarrying activity at Anyama between 2020 and 2021 irreversibly damaged much of the Bété I site, erasing priceless evidence of our past.
“It was absolutely heartbreaking,” said one researcher, recalling the moment they discovered their excavation site had been lost to road construction.
This serves as a stark reminder of how fragile our connection to deep history is. As cities expand and land-use pressures grow, sites like Bété I are at risk of disappearing before they can reveal their secrets.
The discovery at Bété I is not an isolated revelation—it is part of a broader pattern reshaping how we understand early Homo sapiens.
For decades, the dominant narrative of human evolution was one of a singular African origin, with populations expanding from one or two key sites. But mounting evidence suggests that our ancestors were far more dispersed across the continent, adapting to deserts, mountains, and—now we know—dense rainforests.
“This association confirms the predictions of the pan-African model of human evolution, and highlights the importance of Africa’s many regions and ecosystems in this process,” the study concludes.
This means that instead of viewing Homo sapiens as evolving in a single “cradle of humanity,” we should see them as part of a broader, interconnected web of populations, experimenting with survival strategies across vastly different environments.
The rainforest discovery in Côte d’Ivoire is more than just a fascinating footnote in our species’ story—it is a fundamental shift in how we perceive early human adaptability. If people were living in the heart of the rainforest 150,000 years ago, it suggests that the seeds of human ingenuity—our ability to shape, exploit, and endure in different environments—were sown far earlier than we once believed.
This finding reinforces an emerging truth: our ancestors were not just wanderers following herds across grasslands. They were pioneers, carving out lives in every ecosystem they encountered. And as we continue to uncover more of these hidden histories, the story of human evolution will only grow richer, more complex, and—perhaps most importantly—more complete.
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“Multiple hominin dispersals into Southwest Asia over the past 400,000 years”
Nature, 2021. DOI: 10.1038/s41586-021-03863-y -
“A weakly structured stem for human origins in Africa”
Nature, 2023. DOI: 10.1038/s41586-023-05936-6 -
“Defining the ‘generalist specialist’ niche for Pleistocene Homo sapiens“
Nature Human Behaviour, 2018. DOI: 10.1038/s41562-018-0394-4
