Two footprints -- one left and one right -- stamped in the Mexican desert over 10,000 years ago are the oldest known human footprints in North America. According to new analysis, the tracks, discovered 190 miles south of the Texas border, predate any previous discovery by some 5,000 years.
The footprints tell the story of a hunter-gatherer who marched through a marshy basin in the Chihuahuan Desert long before the Mesoamerican civilizations like the Mayans dominated the Mexican landscape.
“To my knowledge the oldest human prints previously reported in North America are around 6,000 years old,” Nicholas Felstead, a geoarchaeologist at Durham University in the U.K., said in a statement, according to Western Digs. Felstead, who spearheaded the new study of the tracks, was able to date the footprints because they were preserved in travertine, a sedimentary rock containing small traces of uranium. Since scientists know the rate at which uranium decays, becoming thorium, researchers were able to determine the footprints’ age by measuring the ratios of the two elements.
According to their study, published in the Feb. 2014 edition of the Journal of Archaeological Science, North America’s oldest footprints were made around 10,550 years ago. The area where the footprints were found is known to have been home to a diverse group of nomadic hunter-gatherers called the Coahuiltecans who roamed the planes of central Mexico and Texas. According to Ancient Origins, the footprints were discovered in an area called the Cuatro Cienegas Basin, a spring-fed, mineral-rich and marshy desert refuge.
“As the ancient nomadic hunter-gatherers needed to adapt to the increasingly hostile desert conditions, they expanded their ability to find resources, leading to longer cycles of nomadism and possibly the expansion of their unique desert culture right into the 18th Century when they finally become extinct after the arrival of the Europeans,” the team notes in the study.
The oldest North American footprints were actually discovered over 50 years ago during the construction of a highway in northeastern Mexico. According to Western Digs, the fossilized footprints were taken to and stored in a local museum, but the place from where they were excavated was somewhat forgotten.
Then in 2006, scientists returned to the site where the prints were believed to have been found. They actually unearthed an additional 11 tracks in the area, along with ancient pollen from pecan and willow trees. The new tracks were dated back to about 7,250 years ago.
The footprints could help archaeologists draw a broader picture of what early human culture was like at the time the tracks were made.