10,000 Year Old Evidence of Human Settlement Among Earliest Ever Found in Bolivian Amazon

Archaeologists surveying a region of the Bolivian Amazon not known for being inhabited by pre-agricultural communities discovered evidence of human settlers there dating back more than 10,000 years.

The terrain the research team surveyed is often though to be unfavorable to settlement. It is peppered with hundreds of "forest islands" -- small wooded mounds. But an excavation of three these mounds has revealed the forest islands are in fact piles of discarded shells, a dense accumulation of freshwater snail shells and animal bones as well as charcoal, forming a midden, or an old dump for domestic waste.

The discovery of the shell middens, which Bolivian archaeologist Jose Capriles, of the University of San Andres in La Paz, thinks were created by hunter-gatherer communities more than 10,000 years ago, places human settlement in the region much earlier than previously known.

"The challenge for the research was to demonstrate that these accumulations had been made by human beings and not, let's say, by other agents, such as birds or other animals. The evidence appears to us to be very strong after much analysis," Capriles said, according to Fox News Latino, which cited the Spanish-language news outlet EFE.

In an abstract to the research, which Capriles and his colleagues published in the open-access journal PLOS One, the authors report that the shell middens "provide evidence for early to middle Holocene occupation and illustrate the potential for identifying and interpreting early open-air archaeological sites in western Amazonia."

"The existence of early hunter-gatherer sites in the Bolivian lowlands sheds new light on the region's past and offers a new context within which the late Holocene 'Earthmovers' of the Llanos de Moxos could have emerged," the researchers wrote.

Lead study author Umberto Lombardo, a geographer from the University of Bern, Switzerland said the discovery is "the oldest archaeological sites in western and southern Amazonia," according to Sci-News. "These sites allow us to reconstruct 10,000 years of human-environment interactions in the Bolivian Amazon."