DNA retrieved from ancient feces in the Paisley Cave system in Oregon, along with arrowheads, indicates that there was a previously unknown pre-Clovis population living in the Pacific Northwest.

A University of Oregon team radiocarbon dated 190 objects including coprolites, bones, and other artifacts retrieved from excavations in the extensive cave system. This indicates a separate population that was different from the Clovis culture.

It appears that the Western culture developed separately and moved east, while the Clovis population moved from New Mexico towards the west. It’s possible that the two populations could have met each other and overlapped at some period in time.

“From our dating, it appears to be impossible to derive Western Stemmed points from a proto- Clovis tradition,” said University of Oregon lead researcher Dennis L. Jenkins. “It suggests that we may have here in the Western United States a tradition that is at least as old as Clovis, and quite possibly older. We seem to have two different traditions co-existing in the United States that did not blend for a period of hundreds of years.”

The coprolites’ DNA could not be exactly carbon tested, but researchers were able to date the fibers present in the ancient feces. They indicated the presence of peoples of Siberian origin about 13,000 years ago living in Oregon.

The prevailing theory used to be that the Clovis peoples were the first settlers in the Americas. Now the University of Oregon research has proved that there were humans living there even earlier.

“The results of this study are exciting, because they show that the hypothesis that the Clovis people were the first Native Americans, which has been the prevailing idea for the last decades, is wrong,” said paper co-author Michael Hofreiter of the University of York in the UK. “Now researchers need to come up with a new model for the settling of the Americas.”