While tropical rain forests are quite biologically diverse, they are not necessarily the ideal habitat for humans. Still, humans have relied on the ecosystem for a very long time. However, a new study indicates that early humans may have relied on the rain forests for at least 20,000 years, which may be thousands of years longer than we first thought.
This study actually begins with the discovery of human teeth fossils in Sri Lanka. Looking at this teeth, researchers could only speculate what the prehistoric humans may have been eating.