Scientists believe birds - which, unlike people, lack heat receptors and don't wince, or worse - when eating the spicy "berry-like" fruits, and spread their seeds across vast areas.
Now, researchers at the University of Colorado say a previously collected fossil shows they were growing in the Americas as much as 50 million years ago - much earlier than the 15 million years ago previously thought.
Study senior author, Stacey Smith - an associate professor in the Department of Ecology and Evolutionary Biology - said finding a fossil that upends settled facts is unexpected.
"All of these sort of distinctive members of the family made of eggplants, chile peppers, tobacco," said Smith, "all of these were around long, long before humans ever encountered them. So they were sort of hanging out waiting for us," Smith said.
As of March 2023, "roasting green chile" is now the official scent of New Mexico. Lawmakers approved and the governor signed a bill making it the first state in the country with an official aroma.
It's estimated the Land of Enchantment produced a whopping 53,000 tons of the peppers in 2022.
Researchers say the chile-pepper fossils originally were collected from the Green River Formation in northwestern Colorado. The findings challenge the previous scientific understanding that nightshades originated from South America.
Smith said she's a bit awed and happy she's able to relate how the fossil discovery has transformed her understanding of plant diversification.
"'Oh that's a fossil of that kind of lizard' or 'That's a fossil of this kind of plant,'" said Smith. "So, it just so happens that we are the people who study those kind of plants and we look at that fossil and say, 'Hey, that's a chile pepper' - and we're 100% certain that it's nothing else."
The findings were recently published in New Phytologist, noting the entire nightshade family - including peppers, tomatoes, potatoes and more - is much older and was more widespread than previously documented.
