New research has revealed the key role that forests have played in early human evolution. For the first time, it suggests that early humans lived and thrived in Côte d’Ivoire rainforests more than 150,000 years ago—more than 80,000 years earlier than past estimates.
The research, published in Nature, builds on the work of co-author Professor Yodé Guédé of l’Université Félix Houphouët-Boigny – who, in the 1980s discovered stone tool artefacts as part of an Ivorian-Soviet survey of the Côte d’Ivoire rainforest.
“Several climate models suggest the area could have been a rainforest refuge in the past as well, even during dry periods of forest fragmentation,” according to Professor Eleanor Scerri, the study’s senior author. “We knew the site presented the best possible chance for us to find out how far back into the past rainforest habitation extended.”
Professor Scerri, leader of the Human Paleosystems research group from the Max Planck Institute of Geoanthropology – a group of global researchers exploring the role of human development on agriculture – mounted a mission to re-investigate 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,” said Dr James Blinkhorn, a researcher at the University of Liverpool and member of the Human Paleosystems research group.
Wood Central understands that the study took place just in time, as the site has since been destroyed by mining activity:
“Before our study, the oldest secure evidence for habitation in African rainforests was 18 thousand years ago, and the oldest evidence of rainforest habitation anywhere came from southeast Asia about 70 thousand years ago. This pushes back the oldest known evidence of humans in rainforests by more than double the previous estimate.”
Dr Eslem Ben Arous, a researcher at the National Center for Human Evolution Research (CENIEH), the Human Paleosystems research group, and the study’s lead author.
The researchers used several dating techniques, including Optically Stimulated Luminescence and Electron-Spin Resonance, to arrive at a date roughly 150 thousand years ago. At the same time, sediment samples were investigated for pollen, silicified plant remains called phytoliths, and leaf wax isotopes. Analyses indicated the region was heavily wooded, with pollen and leaf waxes typical for humid West African rainforests. Low grass pollen levels showed that the site wasn’t in a narrow strip of forest but a dense woodland.
“This exciting discovery is the first of a long list as other Ivorian sites are waiting to be investigated to study the human presence associated with rainforest,” according to Professor Guédé.
“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?”
- More information: Eleanor Scerri, Humans in Africa’s wet tropical forests 150 thousand years ago, Nature (2025). DOI: 10.1038/s41586-025-08613-y. www.nature.com/articles/s41586-025-08613-y Journal information: Nature
