Scientists thought treacherous conditions prevented early humans from living in rainforests, but new research suggests there was human activity in these regions 12,000 years earlier than was previously believed.
In the past, researchers have suggested that rainforests were inhospitable to early humans because they were difficult to navigate and there were fewer animals to hunt, the University of Oxford reported. New research provides "tantalizing hints" that humans occupied the rainforest as far back as 45,000 years ago.
"The isotopic methodology applied in our study has already been successfully used to study how primates, including African great apes, adapt to their forest environment. However, this is the first time scientists have investigated ancient human fossils in a tropical forest context to see how our earliest ancestors survived in such a habitat," said co-author Professor Julia Lee-Thorp from Oxford University.
To make their findings, a team of researchers looked at the fossilized teeth of 26 humans from between 3,000 and 20,000 years ago. The teeth were excavated from archaeological sites around Sri Lanka. The analysis revealed the majority of the studied humans ate a diet that came from an "intermediate rainforest" environment. The findings highlight the impressive adaptability of our early ancestors.
"This is the first study to directly test how much early human forest foragers depended on the rainforest for their diet. The results are significant in showing that early humans in Sri Lanka were able to live almost entirely on food found in the rainforest without the need to move into other environments. Our earliest human ancestors were clearly able to successfully adapt to different extreme environments," said Lead author, Patrick Roberts, a doctoral student specializing in the investigation of early human adaptations from Oxford's Research Laboratory for Archaeology and the History of Art.
The findings were published in a recent edition of the journal Science.