Avocados are a true superfood. Dense, buttery vitamins, fats and fiber scoops, all hand-sized packages.
We have worked for a long time to make them do this. According to a paper published Monday in Proceedings of the National Academy of Sciences, people today called Honduras made avocado part of their diet at least 10,000 years ago, and intentionally improved it over 7,500 years ago.
This means that the domestication of fruits at this site began thousands of years before the arrival of more commonly studied plants such as corn.
“People were raising and growing forests,” said Amber Vanderworker, anthropology professor at the University of California, Santa Barbara and the author of the paper, long before they planted crops in the fields.
Avocados first occurred in central Mexico about 400,000 years ago. They were originally dispersed by megafaunas: giant ground sloths, elephantin gonpozas, and intense toxodones all rambled them regularly, choking them and drinking hazard-sized pits and everything. By the end of the Pleistocene era about 13,000 years ago, megafauna had spread oily fruits in central and northern South America, helping to diversify into at least three different species.
However, the massive extinction that ended the Pleistocene caused the avocado to become stuck. Without the animals large enough to eat the whole animal and spread the seeds, the range began to shrink. At this point, “humans intervened,” said Doug Kennett, professor of environmental archaeology at the University of California, Santa Barbara and author of the paper. Without the megafauna, these humans, who would now need a new food source, began growing fruits and “save the avocados,” said Dr. Kennett.
In the new study, the researchers focused on a western Honduras site called El Gigante. For generations there, humans left behind mountains of abandoned squash seeds, corn nuclei, agave leaves and more. Archaeologists have sifted through everything for about 20 years.
To learn about how El Gigante people enjoyed avocados, researchers saw the “long-term garbage pile” and dozens of seeds in thousands of skin fragments, Dr. Vanderworker said. They used radiocarbon dating to chronologically arrange these scraps, measuring skin thickness and seed dimensions.
By comparing seeds and skin sizes over time, the team was able to track how humans shaped the fruit. Early on, people “were just picking wild fruit from trees when needed,” the trash cans were littered with cherry-sized seeds and thin bits of skin, Dr. Vanderworker said.
In the layer about 7,500 years ago, the seeds have grown and the skin is more robust. This suggests that people are pruning some branches and new fruits to manage existing trees and encourage the remaining branches to grow larger.
In the 4,500-year-old layer, seeds reached the size of apricots and the thickness of the skin was pushed beyond the natural changes in the plant. Tree culturalists preferred large fruits and large amounts of crusts that help preserve and transport.
The study said “in addition to 10,000 years of new evidence on the use of avocados,” said Tom Dilehay, a research professor at Vanderbilt University who was not involved in this particular study. He said he found similar signs of long-standing avocado fun in northern Peru. Other evidence has been found in Mexico, Colombia and Panama. Dr. Dillehay predicts that as research continues, more sites and more types of engineered edible plants will be discovered.
The discovery also continues to reform the concept that food domestication began with animals and grain grains. Dr. Kennett said that the very much effort that early avocado growers had made on the plant was “not what was imagined 10 or 15 years ago.”
The concept of plant breeding comes and goes, but some things are more timeless. One reason you want to grow thick avocado skins is the ease of scooping up, says Dr. Vanderworker, which inspires other delicious imaginations.
