People moved into rainforests much earlier than thought

In at least one part of the world, humans had adapted to living in rainforests by 20,000 years ago, about 10,000 years earlier than previously thought, a new study finds.

Archaeologist Patrick Roberts of the University of Oxford and his colleagues analyzed chemical signatures of teeth from 26 individuals that lived in Sri Lanka from 20,000 to 3,000 years ago. That evidence reflects year-round consumption of rainforest plants and fruits, the researchers report in the March 13 Science. At least on this South Asian island, Stone Age humans found ways to survive full-time in and on the fringes of jungles that included a few open spaces, the researchers say.

Several previous finds had hinted that humans occupied South Asian rainforests as early as 46,000 years ago. But it was unclear whether those stays were brief or long-term. Some researchers have speculated that it took until around 10,000 years ago for foraging groups to figure out how to find enough food and fend off predators well enough to survive year-round in rainforests.