Jan Bartek – AncientPages.com – Rainforests, a significant global biome, were once believed to be uninhabited by humans until recent times. However, new evidence indicates that humans lived in African rainforests at least 150,000 years ago. Our species originated in Africa around 300,000 years ago, yet our evolution’s ecological and environmental contexts remain largely unexplored. Rainforests have often been overlooked as potential habitats due to their perception as natural barriers.
Credit: Pixabay – fifthplanett – Public Domain
A recent study by an international team of researchers challenges this notion with findings that suggest human habitation in rainforests within present-day Côte d’Ivoire occurred much earlier than previously thought. The research highlights that human groups resided in these environments at least 150,000 years ago and suggests that human evolution took place across diverse regions and habitats.
The discovery’s narrative began in the 1980s when co-author Professor Yodé Guédé from l’Université Félix Houphouët-Boigny conducted initial investigations during a joint Ivorian-Soviet mission. This early study uncovered a deeply stratified site with stone tools within today’s rainforest area; however, the age of these tools and the site’s ecology at the time of deposition remained undetermined until now.
“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 Paleosystems 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 Paleosystems team therefore 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,” says Dr. James Blinkhorn, researcher at the University of Liverpool and the Max Planck Institute of Geoanthropology. The renewed 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 around 18 thousand years ago and the oldest evidence of rainforest habitation anywhere came from southeast Asia at about 70 thousand years ago,” explains Dr. Eslem Ben Arous, researcher at the National Center 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.”
The researchers employed various dating methods, such as Optically Stimulated Luminescence and Electron-Spin Resonance, to estimate the age of the site at approximately 150 thousand years ago.
Stone tools like this one, excavated at the Anyama site, reveal that humans were present at the rainforested site roughly 150,000 years ago. Credit: Jimbob Blinkhorn, MPG
Concurrently, sediment samples underwent separate analyses for pollen, silicified plant remains known as phytoliths, and leaf wax isotopes. These analyses revealed that the area was densely forested, with pollen and leaf waxes characteristic of humid West African rainforests. The minimal presence of grass pollen suggested that the location was not merely a narrow strip of forest but rather a substantial expanse of dense woodland.
“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.
“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?”
The study was published in Nature
Written by Jan Bartek – AncientPages.com Staff Writer
