Analysis of ancient human and animal remains suggests that pre-colonial peoples in the Bolivian Amazon likely fed ducks more than 1,000 years ago, a study says.

Research published in journal Nature Human behavioralso suggests that these populations were largely dependent on maize agriculture at certain times.

Together, these findings shed light on how ancient humans interacted with Amazonian ecosystems, while providing direct evidence for animal management in pre-colonial times.

Over the last decade or so, multidisciplinary research has changed our understanding of the history of the Amazon basin. Previously, the region was seen as highly unfavorable for food production and large-scale human societies in ancient times.

However, recent studies have begun to reveal evidence of low-density urban societies, as well as the domestication and management of various plant species—such as cassava, squash, sweet potatoes, yams, and especially maize—in certain areas. forest stretching back thousands of years.

Despite this, “direct insights” into human interactions with certain crops and especially animals remain rare in the vast area of ​​the basin, which covers roughly 2.7 million square miles of the South American continent. This lack of evidence is particularly the case in the parts of the Bolivian Amazon that were once inhabited by the Casarabe people.

This pre-colonial culture, dated between AD 500-1400, is known for the nearly 200 large monumental mounds it built in the Llanos de Mojos region, interconnected by roughly 600 miles of canals and dikes.

“The sheer volume of the sites and their architectural arrangement, divided into a four-tiered settlement system—from large primary centers (150-300 hectares) to small forest islands (around 0.3 hectares)—suggest that the people of the Casarabe culture created a new social and public landscape through monumentality, leading to low-density urbanism,” the authors wrote in the paper.

In their study, the researchers analyzed the skeletal remains of 86 humans (both male and female) and 68 animals (including birds, fish, mammals and reptiles) found at a site in the Llanos de Mojos associated with the Casarabe culture. The remains date from 700 to 1400 AD.

The work involved what the researchers call “stable isotope analysis” — which examines the ratios of specific isotopes preserved in ancient bones and teeth to shed light on dietary and environmental interactions. Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.

Different plants and animals have different isotopic signatures. By analyzing them, scientists can determine what types of food ancient people or animals ate, offering valuable insights into their ecological roles and livelihoods.

The team’s analysis revealed that maize was a common component of the human diet for all individuals in the sample.

The data suggested that maize consumption peaked between 700 and 800 AD, when these populations appeared to depend on the crop, before its dietary importance declined between 1100 and 1400 AD.

Among the animal remains analyzed were those of Muscovy ducks, a type of large waterfowl native to Central and South America. The team’s work revealed that the ducks in the sample appear to have been deliberately fed corn as early as 800 AD – and may even have been domesticated around this time.

“Musk ducks are known to be the only domesticated vertebrate in all of the lowlands of South America, evident from the archaeological record and from the colonial records of domesticated musk ducks in the Llanos de Mojos; however, understanding of this process has remained largely unknown. ” wrote the authors.

“The data presented here support that humans have been feeding and raising musk ducks in the Bolivian Amazon since [A.D.] 800 and at the same time emphasizes the role of maize in the domestication process.”

The steady decline in reliance on maize as a staple crop after AD 800 that the authors observed could be an indication that the Casarabe people began to diversify their agricultural practices or began to increase trade with other populations.

Maize was already cultivated in the Bolivian Amazon before the Casarabe culture emerged around 500 AD, but the crop likely allowed the group to expand because it became a staple of the diet, the authors say.

Link

Hermengildo, T., Prümers, H., Jaimes Betancourt, C., Roberts, P., O’Connell, TC, (2024). Stable isotope evidence for pre-colonial maize agriculture and animal husbandry in the Bolivian Amazon. Nature Human behavior. https://doi.org/10.1038/s41562-024-02070-9