Modern humans, Homo sapiens, emerged approximately 300,000 years ago, but their presence in rainforests is a more recent chapter in human history. Previously, the earliest archaeological evidence placed humans in these lush environments around 70,000 years ago. However, groundbreaking new research suggests a significantly earlier timeline, pushing back our rainforest habitation by over 80,000 years.
This revelation comes from a re-examination of an archaeological site in present-day Côte d’Ivoire. An international team of researchers asserts that humans occupied this rainforest region as far back as 150,000 years ago, significantly earlier than previously estimated. This study, published in Nature, reinforces the understanding that human evolution was shaped by a diverse range of landscapes, not solely by open savannas and grasslands as previously believed.
“Prior to this study, the oldest confirmed evidence of human presence in African rainforests dated back to approximately 18,000 years ago,” explains Eslem Ben Arous, lead author of the study and archaeologist at the Max Planck Institute of Geoanthropology. “The oldest global evidence of rainforest habitation was around 70,000 years ago in Southeast Asia. Our findings more than double the previous oldest known estimate for rainforest dwelling.”
The site in Côte d’Ivoire was initially investigated in the 1980s by Yodé Guédé, a co-author of the current study from the Université Félix Houphouët-Boigny. Guédé and his team uncovered a stratified site containing stone tools, but the technology at the time limited their ability to accurately date the artifacts.
“With Professor Guédé’s guidance, we relocated the original trench and re-examined it using cutting-edge techniques unavailable thirty to forty years ago,” states James Blinkhorn, an archaeologist at the University of Liverpool and a participant in the study. Utilizing these advanced methods, the team dated the site to 150,000 years ago. Analysis of plant remains within sediment samples confirmed that the region was indeed a rainforest during that period.
This discovery significantly alters our understanding of early human habitats and their adaptability. It challenges the traditional narrative of human evolution centered around savannas and grasslands.
“This study confirms that ecological diversity played a crucial role in the evolution of our species,” says Eleanor Scerri, senior author of the study and archaeologist at the Max Planck Institute of Geoanthropology. “It reflects a complex history of Homo sapiens population subdivision, with different groups inhabiting various regions and habitat types.”
This research also raises intriguing questions about the impact of early humans on rainforest ecosystems. “We now need to investigate how these early human niche expansions affected the plants and animals that shared the same environment,” adds Scerri. “In other words, how far back does human alteration of pristine natural habitats extend?”
The savanna hypothesis of human evolution posits that our ancestors’ transition from forested environments to open landscapes millions of years ago spurred the development of key traits like bipedalism, tool use, and hunting strategies. This new research challenges this hypothesis by highlighting the role of rainforests in the development of modern humans. It questions what further evolutionary adaptations may have arisen when some human populations returned to life among the trees. Furthermore, it prompts important considerations about the potential impact our species had on these rainforests upon their return.
This study fundamentally rewrites the history of prehistoric human habitats and opens new avenues for exploring the long-overlooked significance of rainforests in the story of human evolution. It underscores the complexity of human adaptation and the diverse environments that shaped our species.
