Ancient footprints discovered in New Mexico show that humans were walking across North America between 21,000 and 23,000 years ago, researchers said Thursday.
If the dating of the footprints, found at White Sands National Park in New Mexico, are accurate, they would represent the earliest evidence of human life anywhere in North or South America, according to a study published in Science.
David Bustos, who co-authored the study, told NBC News that the discovery was exciting for scientists.
“We’d been suspicious of the age for a while, and so now we finally have that it’s really exciting,” Bustos told NBC News. “One of the neat things is that you can see mammoth prints in the layers a meter or so above the human footprints so that just helps to confirm the whole story.”
The footprints were first spotted in 2009 in a dry lake bed in White Sands National Park, according to The Associated Press. Scientists at the U.S. Geological Survey recently analyzed seeds lodged in the footprints to determine their approximate age, ranging from around 22,800 and 21,130 years ago, the AP reported.
The ancient ditchgrass seeds were found in layers of hard earth both above and below the human footprints at the site and were radiocarbon-dated to determine their age, according to Science.
“The evidence is very convincing and extremely exciting,” Tom Higham, an archaeological scientist and radiocarbon-dating expert at the University of Vienna, told Nature.com. “I am convinced that these footprints genuinely are of the age claimed.”
Oregon State University, Corvallis, archaeologist Loren Davis called the discovery “potentially groundbreaking.”
“If that’s true … it’s going to be a revolution in the way that we think about archaeology in the Americas,” Davis, who was not involved with the study, told Science. “It might reignite debates about how people first reached the continent from Asia. But Davis and others would like corroboration of the surprising dates before they rewrite their understanding of when and how people arrived.
“I think this is probably the biggest discovery about the peopling of America in a hundred years,” Ciprian Ardelean, an archaeologist at Autonomous University of Zacatecas in Mexico who also was not involved in the work, told The New York Times. “I don’t know what gods they prayed to, but this is a dream find.”
The size of the footprints led researchers to believe that at least some of them were made by children, according to the AP.
There has been a debate for years whether humans arrived in North America from Siberia before or after what is known as the Last Glacial Maximum -- what scientists call the height of the last ice age, up to 26,000 years ago, NBC News reported.
Matthew Bennett, a professor of environmental and geographic sciences at Bournemouth University in the United Kingdom, said a major question has been answered.
“A footprint is a really good, unequivocal data point,” Bennett told NBC News. “That’s the importance of this site -- we know they were there.
“You can now look at the oldest sites and say, ‘We know they were there during the Last Glacial Maximum,’ so maybe some of these oldest sites are also reliable.”