The oldest chili pepper specimen may be from present-day Colorado

The spicy treat is older than scientists thought—with a surprising origin story.
Scientists recognized the 50 million-year-old pepper by the unique shape of its calyx teeth: spikes on the end of the fruiting stem that hold on to the pepper. Rocío Deanna

It’s hard to imagine life without the nightshade family. It includes the likes of tomatoes, potatoes, peppers, and eggplants—some of the essential ingredients for a healthy diet–and delicious recipes. But, it turns out one of these tasty flowering plants has a longer history in North America than scientists previously believed. 

According to a March paper in the journal New Phytologist, the chili pepper may have been growing roots in present-day Colorado at least 50 million years ago—quite a bit earlier than scientists originally believed.  Previously, the chili pepper’s origin was placed 15 million years ago in South America. The newest theory emerged when a postdoc and an undergraduate student at University of Colorado-Boulder discovered a fossil of a plant that uncannily resembles the chili pepper, notably through its spiky ends on a fruiting stem called the calyx. 

“The world has maybe 300,000 plant species. The only plants with that kind of calyx is this group of 80 or 90 species,” Stacey Smith, senior author of the paper and associate professor of evolutionary biology at CU Boulder, said in a press release.

[Related: 5 heirloom foods that farmers want to bring back from obscurity.]

The well-preserved specimen was revealed in the Green River Formation, a site chock full of Eocene fossils and discoveries. But, it ended up not being as rare as the authors thought at first—two more similar chili pepper deposits from Green River were hidden in the CU Boulder collections and another at the Denver Museum of Nature and Science. These fossils were uncovered in the 1990s, but it certainly isn’t unheard of for discoveries to lay in wait until the right scientists come along

The Green River Formation is a marvel for capturing the Eocene, which lasted from around 34 to 56 million years ago and marked the beginning of the era of mammals. During this epoch, the amount of carbon in the atmosphere was around double that of today, paving the way for palm trees to grow in Alaska and a lack of ice driving sea levels 500 feet higher than they are currently. 

So what could’ve happened that caused the gap between when chili peppers were evolving in Colorado and when they appeared in South America during the Miocene? The authors theorize that modern birds, which have been able to fly long distances for some 60 million years, could’ve carried seeds and plants in their poop or stuck to their bodies. 

Through birds, chili peppers would’ve made their way to South America. Since the latest discovery puts the evolution of chili peppers back to the days of Gondwana, transoceanic travel may have been unnecessary. Birds could simply fly across shorter watery distances or via a chain of volcanic islands, the scientists wrote in the new paper. 

[Related: Oldest evidence of digested plants in a roughly 575-million-year-old creature’s gut.]

Nevertheless, this discovery puts the oldest chili peppers in a place that no longer has many native nightshades or any chili peppers at all. “These chili peppers, a species that we thought arose in an evolutionary blink of an eye, have been around for a super long time,” Smith added. “We’re still coming to grips with this new timeline.”

So next time you break out a meal of Colorado-style chili, that bowl of goodness might have even more local roots that anyone realized.