© 2023 KUNR
Celebrating 60 years in Northern Nevada and the Eastern Sierra
Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations
KUNR Public Radio is a proud partner in the Mountain West News Bureau, a partnership of public media stations that serve Nevada, Colorado, Idaho, Montana, New Mexico and Wyoming. The mission is to tell stories about the people, places and issues of the Mountain West.

Chili peppers’ evolutionary origins have Colorado flavor, new study shows

This is a close-up image of a chili pepper fossil on a light brown stone that was identified in the CU Boulder Museum of Natural History.
Courtesy Of Rocío Deanna
CU Boulder
CU Boulder’s Rocío Deanna and Abel Campos identified this chili pepper fossil in the CU Boulder Museum of Natural History collections by the unique shape of its calyx teeth: spikes on the end of the fruiting stem that hold on to the pepper.

Chili peppers are an important ingredient for many foods. Now, a new study shows that they have been around for much longer than we thought, with origins in parts of the Mountain West.

Scientists previously thought chili peppers evolved in South America 15 million years ago. But their roots may go back 50 million years – including in North America. That’s according to researchers from the University of Colorado Boulder, whose findings were published in the journal New Phytologist.

The researchers compared chili fossils from Colombia to plant fossils from the Green River Formation in northwestern Colorado. The fossils’ calyx teeth – the little spikes on the end of the stem that hold on to the pepper – had the same unique shape. Researcher Rocío Deanna and student Abel Campos spotted the similarities while surveying fossils at the CU Boulder Museum of Natural History.

“They have a history here, they have a little story,” said Stacey Smith, a study author and associate professor of evolutionary biology at CU Boulder. “So, it reminds me that Colorado didn't always used to be this dry and forced us to turn on humidifiers – that it used to be pretty lush, pretty tropical.”

Smith says they can’t be sure of the exact shape or color of the ancient chili that was collected from Colorado. But they believe it was smaller than a modern version – and possibly quite spicy.

This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Nevada Public Radio, Boise State Public Radio in Idaho, KUNR in Nevada, the O'Connor Center for the Rocky Mountain West in Montana, KUNC in Colorado, KUNM in New Mexico, with support from affiliate stations across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting.

Kaleb is an award-winning journalist and KUNR’s Mountain West News Bureau reporter. His reporting covers issues related to the environment, wildlife and water in Nevada and the region.