Niba: Chocolate being one of the world’s most delicious foods, you’d think we would know everything about it. What kinds there are, how to grow it… where it comes from. But that last thing? We actually aren’t sure.

I mean, sure, chocolate comes from the cacao tree, but the versions of that tree we know and love, didn’t spring out of the ground on their own. Somebody domesticated wild cacao. It’s just… nobody really  knows who, or when… or where.

But if we want chocolate for the long haul, and  boy do we, it’s in our best interests to find out.

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[0:32] Niba: The first part of solving this is knowing where cacao trees started. And that, at least, is something researchers seem to agree on. Today, Theobroma cacao is grown  in the tropics around the world. But the plant’s origin story starts around 8 to 13 million years ago, in northwest South America.

Researchers have found that wild Theobroma cacao trees there, or T. cacao trees, have the highest levels of genetic diversity — in other words, from tree to tree, there’s more variation in the cacao’s DNA. That matters, because when a species spreads out, and some individuals break away from the pack, they can’t bring all of  their family’s different genes with them. If a lone cacao has version  number 32 of some gene, that’s the only version they  can pass on to their offspring.

So, researchers have proposed that these younger populations should get less diverse over time. By that logic, if you find a group with the highest genetic diversity, you’ve probably found the original population — or, at least, something close. So, T. cacao likely started in South America.

But most chocolate doesn’t come from wild cacao: It comes from domesticated trees that have been intentionally bred to enhance things like flavor. Given where cacao started, you might guess that people in South America were the first to domesticate the plant, and start  turning it into the most delicious tree on Earth. But that’s not what some researchers have proposed.

Credit for first domesticating cacao was initially given to the Olmec, who lived in what’s now Mexico from about 1200 to 400 BCE. We know that cacao was important to them, and was made into food and drinks, and even used as currency. Plus, there’s genetics.

For instance, a 2018 paper looked at a variety of cacao called Criollo. Traditionally, researchers have thought Criollo was bred into existence in Mesoamerica — a region that includes parts of Central America and Mexico. And this study supported that, with evidence that Criollo plants were being bred to enhance things like stimulant levels and  disease resistance about 3600 years ago.

But does that mean the Olmec domesticated cacao first? This is where the plot thickens. For one, cacao seeds aren’t actually big on traveling.

They’re fussy little guys that don’t stay viable for long, and they need perfect conditions to spread. So, even if the Olmec were domesticating  cacao, where did they get the seeds? They could have ended up in Mexico thanks to monkeys or squirrels.

Or maybe T. cacao existed over a much larger area at some point. But more likely, it was people who brought the plant north. People in Mesoamerica have been trading with people in South America for millennia.

And studies suggest that the Olmec weren’t getting wild seeds: 3800 years ago, they were getting cacao that had already been domesticated. So, someone else did it first. In another 2018 paper, other researchers studied  an archaeological site in what’s now Ecuador, which was home to the Mayo-Chinchipe.

The site dates back 5300 years — which makes it about 1500 years older than the oldest evidence of cacao in Central America and Mexico. This team found three different types of evidence that ancient Mayo-Chinchipe pottery was once used to hold cacao. They found grains of starch from cacao plants, as well as chemical signatures of Theobromine – a compound found in cacao, especially domesticated varieties.

And they even found T. cacao DNA — DNA that was different from both wild and modern varieties. If nothing else, this suggests people in South America were using cacao way before those up north. But were they actually domesticating it?

Here’s where a 2024 paper comes in. In this one, researchers tested more than 350 ceramics not just from the Mayo-Chinchipe, but from 19 cultures across South America. Once again, they found T. cacao DNA going back 5000 years, and chemical signatures linked to the plant.

And not only that, but they also found evidence that different varieties of cacao were being bred across the continent. Like, on the Pacific coast, cacao trees were being bred with each other to produce new varieties adapted to new environments. And also?

The researchers found evidence of ancient  Criollo trees, which supposedly didn’t show up until more than a thousand years  later, thanks to Mesoamerican farmers. Based on this, it seems like multiple cultures across South America were already domesticating T. cacao and trading the plants with each other  by about 5000 years ago. Then, much later, the Olmec were  introduced to domesticated cacao by trade.

That said, it’s very possible that people  in Mesoamerica kept breeding the plant to enhance features they cared about, shaping the cacao we have today. Or maybe one way or another, people like the Olmec did get their hands on wild cacao, and started breeding those from  scratch to make new varieties. There’s still a lot of uncertainty, but researchers are looking into this — and not just because we love cacao.

Understanding how this plant was domesticated could not just teach us more about ancient cultures, but help ensure we have our chocolate fix for years to come. Part of domesticating cacao involved adapting it to environments beyond the Amazon. And understanding how that happened could  help us improve the way we breed cacao today — especially as we reckon with climate change.

Cacao is a pretty fussy plant that only  thrives in stable, tropical conditions. So it’s in our best interests to learn  how to breed them to be successful outside of their perfect little bubbles. It is one of the most  important crops in the world, and a major income source for many countries.

And also? Let’s be honest: We’ve got a lot going on these days. And if we’re expected to be functioning adults in these forever-unprecedented times, at least we can do it with some chocolate.

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