While Americans undoubtedly love chocolate, the ancient Mayans considered cacao trees and their fruit to be a gift from the gods. Cacao trees were only grown in sacred groves, the locations of which were previously unknown to researchers. Until recently.

Researchers from Brigham Young University, including Richard Terry — a recently retired professor of soil sciences — and graduate students Bryce Brown and Christopher Balzotti have been able to identify the locations of sacred Mayan cacao groves, many of which had remained hidden in sinkholes along the Mexican Yucatan peninsula.

“Back in the 1990s, there was a study that found cacao trees growing in sinkholes in Yucatan. This was interesting, because cacao, the plant, requires an atmosphere that is almost 100% humidity all the time,” Terry said. “Well that doesn’t exist in Yucatan, in Yucatan they have a six-month dry season … but we know that the Yucatan Maya were using cacao.”

Cacao trees need shade and humidity to grow, conditions uncommon to the Yucatan peninsula. However, the researchers realized that the many sinkholes common in the area contain microclimates with hospitable conditions.

The team performed soil analyses on 11 different sinkholes, and ultimately found evidence of cacao trees in the form of theobromine and caffeine in nine of them. These findings have recently been published in the Journal of Archaeological Science Reports.

Terry and his team developed a new method of soil extraction in order to extract and analyze the soil for the cacao biomarkers, theobromine and caffeine.

“This involved drying the soil samples and passing them through a sieve, covering them with hot water, having them centrifuged and passed through extraction disks, and analyzing the extracts by mass spectrometry,” reads the press release. “To increase the sensitivity of their testing, the research team compared the results of the soil samples to seven control samples with no history of exposure to the biomarkers.”

Additionally, archaeologists were able to find evidence of ceremonies or rituals that may have taken place. Their discoveries include staircase ramps, altars, stone carvings and jade, along with ceramics that may have been used as offerings.

“The findings of the BYU study indicate that cacao groves played an important role in ancient rituals and trade routes of the ancient Maya, impacting the entirety of the Mesoamerican economy,” reads a press release distributed by BYU. “A 70-mile Maya ‘highway’ in the area that was the main artery for trade passes near hundreds of sinkholes, so it is likely that the leaders who commissioned the highway development also controlled cacao production. The evidence of cacao cultivation alongside archaeological findings also supports the idea that cacao was important in the ideological move from a maize god to a sun god.”

According to Terry, strictly controls of cacao on these highways was how it retained value.

“Someone controlled ownership, use, and growing of cacao trees in those sinkholes,” Terry said. “So it was controlled, that’s why the money held its value because only certain people at certain locations could grow it.”

The BYU researchers worked with archeologists from the U.S. and Mexico on this project, including researchers from the University of California, Riverside; the University of Miami; State University of New York; Kent State University; Universidad Nacional Autónoma de Mexico; Instituto Nacional de Antropologia e Historia; and the Cultural Heritage and Archaeology in the Maya Area institution.

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