The traces at one place have been revealed as both the earliest known footprints and the oldest solid evidence of humans anywhere in the Americas, showing people lived there between 21,000 and 23,000 years ago – several thousand. years earlier than scientists once believed.
“This is the first unequivocal evidence for humans in the Americas,” said Matthew Bennett, professor of environmental and geographic sciences at the University of Bournemouth in the UK and lead author of the study.
Fossilized human footprints have now been found throughout the eastern part of the national park, where the bed of a now dry ‘paleo-lake’ provides the gypsum-rich soil which is eroded by the wind to create the beds. huge white dunes for which the region is famous.
Any evidence of ancient human habitation had been disputed because it rested on what appeared to be stone tools that could have formed naturally, Bennett said, or on artifacts that could have moved from their original stratigraphic layers.
“A fingerprint is a very good, unequivocal data point,” he said. “That’s the importance of this site – we know they were there. “
The footprints would in turn lend greater credibility to other evidence of early humans in the Americas.
“You can now look at the older sites and say, ‘We know they were there during the last glacial maximum,’ so maybe some of those older sites are also reliable,” he said. declared.
The term “last ice maximum”, or LGM, is how scientists refer to the height of the last ice age, around 20,000 to 26,000 years ago.
It has long been questioned whether humans first arrived in the Americas via a northern route from Siberia before or after the last glacial maximum, when vast patches of ice would have made migration along the coast of Africa impossible. Pacific or across western Canada.
The ancient White Sands footprints now answer that question, suggesting they may have happened as much as 30,000 years ago, thousands of years before the height of the Ice Age, Bennett said.
Although White Sands is now primarily a desert, it was a lush wetland during the time footprints were made and populated by mammoths, land sloths, bovids – cattle – and wild camels, as well. than by the Stone Age humans who hunted them.
The footprints are intertwined with animal tracks and show people must have lived there for at least 2,000 years, Cornell University archaeologist Thomas Urban, co-author of the research, said in an e- mail.
“There are multiple layers of footprints spanning a significant period of time, suggesting a sustained human presence in the region during the Last Ice Maximum, as opposed to a single event,” he said.
Urban has developed the non-invasive use of ground-penetrating radar to reveal footprints below the surface and show researchers the best places to dig.
The smaller footprints made by teens and children outnumber those made by adults, Urban said, perhaps because they were involved in tasks that involved simple work, instead of skilled tasks. like hunting.
“Their presence is just part of ordinary life and should be expected,” he said. Their activities could range from games to chores such as collecting food, water and raw materials for their hunter-gatherer community.
Geologist Cynthia Liutkus-Pierce of Appalachian State University in North Carolina, who has studied ancient human footprints in Tanzania but was not involved in the search for White Sands, said it was often difficult to date just as the fossilized prints were being made, especially when pressed. in layers of mud – as in White Sands – and not in more easily dated volcanic ash.
« [It’s] great to see that this team was able to constrain the date of the footprint formation using radiocarbon dates from the [layers] above and below, ”she said in an email.
Unlike bones or artifacts, footprints are unique in that they have recorded fossilized behavior, and their analysis can provide clues about the carvers.
“Human footprints give us a glimpse into the lives of our ancestors and, in this case, provide detailed information about their daily activities and social dynamics,” Liutkus-Pierce said.