La Chacra forest island in the Bolivian Llanos de Moxos José Capriles, PSU

Evidence of human foragers have been found in the savannahs of the southwest Amazon that date back to between 4000 and 10,600 years ago.

People are thought to have entered the area between 13,000 and 17,000 years ago, but these groups are thought to have moved around often. More settled foraging societies – which have more of an impact on the local land and animals – weren’t thought to have lived in the same region until about 2500 years ago.

But José Capriles at Pennsylvania State University and his colleagues have found evidence to the contrary during their exploration of three Bolivian “forest islands” – circular patches of forest on the savannah that are like an oasis in the desert.


As they dug down to 2 metres below the surface of the soil, they found burned earth, ceramic shards, seeds, charcoal remnants and the remains of five humans. The burials included both men and women.

Five burials were unearthed in the study José Capriles, PSU

Their teeth were complete but heavily worn, which suggests that they were older adults who ate a diet high in shellfish, according to the team. Carbon dating of the soil layers suggests these people were buried between 6250 and 6820 years ago.

Layers excavated beneath the burials included bones of deer, carnivores, armadillos, rodents and a few birds. Remains of fish and eels, which are common in archaeological sites in the area, were also found. The gastropod shells found throughout the sites suggest that these areas were near wetlands and the people inhabiting them collected and transported shellfish to be eaten in their settlements.

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In one of the forest islands, they found clumps of burnt clay that had hardened into ceramics in what may have been a kind of hearth, suggesting that these foragers had persistent or high-temperature fires.

The earliest evidence of these hunter-gatherer societies comes from shell detritus in one of the forest areas, which dates back to around 10,600 years ago. The sites were abandoned several centuries before the emergence of complex agricultural societies in the region.

Journal reference: Science Advances, DOI: 10.1126/sciadv.aav5449