• DNA analysis of more than 350 archaeological artifacts from the Upper Amazon region found cacao particles on 30% of the samples, proving that the fruit was cultivated in South America more than 5,000 years ago.
• Traces were found on ceramic pieces from 19 different pre-Columbian cultures and show genetic mixing between cacao species that were geographically far from each other.
• The discovery verifies the theory that ancient trade routes existed between the Amazon and other regions, like Central America, where cacao was previously thought to have originated from.

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It’s hard to imagine the history that lies behind the cacao trees grown on agroforestry farms in the Amazon today. For a long time, people believed that cacao’s origins lay elsewhere. Archaeological evidence had pointed to what is today southern Mexico and Central America — Mesoamerica — as the birthplace of the domesticated form of the Theobroma cacao tree some 4,000 years ago. It was only believed to have arrived in South America later.

“We would always find cacao trees in the native forest on the Upper Amazon [in Ecuador] and think of the peoples who had lived in the region thousands of years before, but at the time, we had no idea that cacao was native to the region,” says Francisco Valdez, an archaeologist at the French National Research Institute for Sustainable Development (IRD).

At the start of the 2000s, Valdez began studying evidence that would bring new knowledge about the ancient peoples who once prospered in the Upper Amazon. His research focused on the Andean region of the Amazon River Basin, straddling modern-day Ecuador, Peru, Colombia and Venezuela.

Among numerous findings was the surprising detection of cacao DNA on ceramic artifacts dating back thousands of years that had been used inside homes and as burial items. This led to a reevaluation of the fruit’s origin: with South American roots, the evidence showed that cacao was already circulating between 19 different pre-Columbian cultures some 5,500 years ago.

“The most important characteristic of our research is the fact that it further establishes the cultures from the Upper Amazon as innovative peoples who were fundamental in the emergence of civilizational phenomena,” Valdez says. “Now the importance of these cultures is doubly recognized. The Amazonians were capable of enormous civilizational achievements, and regional interaction was an important factor.”

Cacao for the afterlife

The researchers’ work revealed 400 archaeological sites in the region and described interactions that existed between the inhabitants of the Amazon, the Andean highlands, and the Pacific plains and coastline.

Finding cacao particles on ceramic artifacts used more than 5,000 years ago led the study to determine that cacao was already a basic food item among the people at that point in history. “We found this evidence inside burial urns placed with a number of individuals to take into the afterlife. The same evidence was also found in excavations of homes,” Valdez says.

At the time, cacao was prepared as a pulp and drunk as a liquid, or its seeds roasted and powdered for use in elaborate recipes. It was also used medicinally as an antiseptic.

Valdez and his colleagues published their findings in a 2018 study that explained how cacao existed in the Upper Amazon 1,500 years before it was found in Mesoamerica.

 

Studies on cacao intensified in the region following that watershed discovery. DNA testing of more than 350 archaeological objects, from both museum collections and new excavations — encompassing a period of nearly 6,000 years — revealed that about 30% of the objects carried traces of the fruit.

“Genetics is probably the most valuable tool we have, and has revolutionized science over the last 30 or 40 years. And DNA sequencing has changed all our misconceptions on the human and other biological species,” says Valdez, who co-authored a recently published study delving even deeper into the cacao provenance in the Amazon.

The new study looks at how cacao particles found on ceramic objects used in 19 pre-Columbian cultures reveal a genetic mix of cacao species raised in geographically remote regions. This indicates the trade and interaction that must have occurred between the peoples of the Amazona and those on the Pacific coast, as well as the plant’s ability to adapt to different environments.

“These data show us that cacao is a South American plant that was carried along trade routes thousands of years ago away from its point of origin — which lies on the current border between Peru and Ecuador at the foot of the Andes in western Amazonia — to other parts of South America and the Americas,” says Eduardo Góes Neves, director of the University of São Paulo’s Museum of Archaeology and Ethnology (MAE-USP), who wasn’t involved in either the 2018 or 2024 studies.

“This is quite interesting for two reasons: aside from reinforcing the idea that Amazonia is a center of production and agrobiodiversity, it also shows that ancient trade networks existed connecting Central America, North America and South America.”

The researchers suggest that the complex history of cacao’s domestication is the foundation for today’s cacao-farming populations, and that this knowledge could help with management of the plant’s genetic resources in a time of climate change.

Between rivers and mountains

The first historical records of cacao farming in the Brazilian Amazon are linked to colonization by the Portuguese in the last half of the 17th century.

Fernando Mendes is an agricultural engineer who’s been working with cacao for 44 years. He tells stories of how the fruit was fuel for disagreements between the head of the Portuguese empire and Jesuit missionaries, for whom the cacao trade was a substantial source of income.

It’s always been known, however, that the domestication of cacao by the Indigenous peoples of the Americas happened long before the Europeans invaded. “In 1502, when Christopher Columbus was in [what is today] Honduras on his second voyage to America, he came upon an Indigenous canoe with cacao fruit inside. He hadn’t seen the fruit before, and was very impressed with it,” says Mendes, the author of several books on cacao and coordinator of regional research and innovation for the Executive Commission for Cocoa Cultivation Planning (CEPLAC).

He says it’s difficult to know exactly when cacao arrived in what’s today the Brazilian part of the Amazon, and equally complex to pinpoint the time when it began to be farmed — which was more than 5,000 years ago, as proven by the particles found on the ceramic artifacts.

“Its seeds were passed from hand to hand over rivers and mountains as the Indigenous people living here traded and planted. This is how cacao began to be domesticated,” Mendes says. “And we have no date for when that began.”

Mendes says the domestication of cacao over thousands of years in the Amazon made the species more resistant to climate change because the plant became adapted to cultivation beneath the forest canopy, protected from direct sunlight.

Because it’s a perennial plant and doesn’t require the use of fire, cacao helps to mitigate climate change impacts in agroforestry systems and also helps to regenerate the rainforest.

“Since 1996, CEPLAC’s objective in Amazonia has been to provide assistance to farmers growing cacao in areas of the rainforest that have already been altered by humans, never in virgin rainforest,” Mendes says. “According to our data, the cacao program in the state of Pará recuperated some 160,000 hectares [395,000 acres] of land between 1996 and 2023.”

Banner image of cacao fruit harvested in the Peruvian Amazon. Image by Jack Gordon for USAID Digital Development via Wikimedia Commons (CC BY 2.0).

This story was reported by Mongabay’s Brazil team and first published here on our Brazil site on July 1, 2024.