Journal Article
New research shows that humans lived in African rainforests 150,000 years ago. This is more than twice as early as previously thought.
Humans emerged in Africa around 300,000 years ago, before spreading to every continent and biome on earth. Dense tropical rainforests have long been considered barriers to early human habitation—environments too challenging for our ancestors to navigate until relatively recently.
Now, in a new Leakey Foundation-supported study published in Nature, an international team of researchers challenge this view with the discovery that humans lived in West African rainforests by 150,000 years ago.
“Before our study, the oldest secure evidence for habitation in African rainforests was around 18,000 years ago and the oldest evidence of rainforest habitation anywhere came from southeast Asia at about 70,000 years ago,” explains Dr. Eslem Ben Arous, researcher at the National Centre for Human Evolution Research (CENIEH), the Max Planck Institute of Geoanthropology and lead author of the study. “This pushes back the oldest known evidence of humans in rainforests by more than double the previously known estimate.”
Joint Ivorian and Soviet research in the 1980s
The evidence comes from a site called Anyama in present day Côte d’Ivoire on the southern coast of West Africa. The site was first investigated in the 1980s by co-author Professor Yodé Guédé of l’Université Félix Houphouët-Boigny on a joint Ivorian-Soviet mission. The original excavations found stone tools in layers of a deeply stratified site. But at the time, the researchers couldn’t determine the age of the tools. They also didn’t have the technology to determine whether the site was a rainforest at the time the tools were deposited. The results of the original work were only published in Russian publications not accessible to the wider scientific community.
A rainforest refuge
“Several recent climate models suggested the area could have been a rainforest refuge in the past as well, even during dry periods of forest fragmentation,” explains Professor Eleanor Scerri, leader of the Human Palaeosystems research group at the Max Planck Institute of Geoanthropology and senior author of the study. “We knew the site presented the best possible chance for us to find out how far back into the past rainforest habitation extended.”
The Human Palaeosystems team was determined to reinvestigate the site. “ I applied to The Leakey Foundation with this project in mind,” said Professor Scerri, “and I was very lucky that I made the case and the money was granted so were able to go and do this work.”
Archaeologist Dr. James Blinkhorn of the University of Liverpool and the Max Planck Institute of Geoanthropology led an international team of scientists to reopen the site. “With Professor Guédé’s help, we relocated the original trench and were able to re-investigate it using state of the art methods that were not available thirty to forty years ago,” says Dr. Blinkhorn.
Cutting-edge technology
The researchers used several cutting-edge dating techniques, including Optically Stimulated Luminescence and Electron-Spin Resonance. They dated the oldest tool-bearing layer of the site to around 150,000 years old.
The next important thing was to confirm that the area was in fact a rainforest at that time. To do this, they analyzed ancient pollen, silicified plant remains called phytoliths, and leaf wax isotopes. Their analysis indicated the region was heavily wooded, with pollen and leaf waxes typical for humid West African rainforests. Low levels of grass pollen showed that the site wasn’t in a narrow strip of forest, but in a dense woodland.
I want to thank The Leakey Foundation for financing this work. It was a risk, giving someone funding to work in a region of Africa that’s not traditionally associated with human evolution discoveries in an ecosystem which humans are supposed to have avoided. That was quite a brave decision and I think science cannot continue without bravery.
Professor Eleanor Scerri
A story of ecological diversity
“Convergent evidence shows beyond doubt that ecological diversity sits at the heart of our species,” says Professor Scerri. “This reflects a complex history of population subdivision, in which different populations lived in different regions and habitat types. We now need to ask how these early human niche expansions impacted the plants and animals that shared the same niche-space with humans. In other words, how far back does human alteration of pristine natural habitats go?”
“This exciting discovery is the first of a long list as there are other Ivorian sites waiting to be investigated to study the human presence associated with rainforest,” says Professor Guédé.
The research was funded by the Max Planck Society and The Leakey Foundation.
Read the research 🔓
Ben Arous, E., Blinkhorn, J.A., Elliott, S. et al. Humans in Africa’s wet tropical forests 150 thousand years ago. Nature (2025). https://doi.org/10.1038/s41586-025-08613-y
