Ancient footprints give surprising new clues about early Americans

During the height of the last Ice Age, generations of children and teens walked barefoot along a muddy lake in what is now New Mexico, encountering mammoths, giant land sloths and a canine species. extinct known as the terrible wolves.

Today, some 23,000 years later, the fossilized footprints of young people provide new information about when humans first populated the Americas. Unearthed in White Sands National Park by a research team that began work in 2016, the tracks are about 10,000 years older and about 1,600 miles further south than any other known human footprint in America, reported Thursday scientists in the journal Science.

“This is, in my opinion, the first unequivocal evidence of human presence in the Americas” during the last ice age, said Daniel Odess, head of science and research at the US National Park Service and author main report, about the discovery. “Footprints are unmistakably human. “

For decades, many scientists were convinced that humans first arrived in the Americas just 13,000 years ago, reaching the continent after crossing an ice-free land bridge from Asia or by sea. along the Pacific coast on the journey from the African homeland of mankind. Others have argued that they arrived about 16,000 years ago, or even 30,000 years ago. There simply wasn’t enough evidence in the fossil record to settle the debate.

But recently discovered footprints show humans lived in the American Southwest at a time when massive ice caps blocked the way for migrants from Asia to the New World, the researchers said.

“It really gives a boost to the argument that humans lived in North America at this time, much earlier than previously thought,” said Kevin Hatala, paleobiologist at Chatham University in Pittsburgh. which studies the evolution of human walking. “If the dating holds, then it adds to this growing body of evidence that humans are in North America during this time. He was not involved in the discovery.

In total, a research team led by scientists from Bournemouth University in Poole, England, discovered 61 human tracks preserved in seven layers of silt, clay and sand.

In most cases, fossilized prints are impossible to date with precision. But these were interwoven with sediments containing seeds of aquatic plants that once grew along the lake. Radiocarbon dating of the plants showed that the footprints were 21,000 to 23,000 years old.

The fingerprints represent 10 to 15 individuals and were made over a period of 2,000 years, mostly by children and adolescents, the scientists said. No one knows what attracted people to the place. So far, there are no signs of campfires, tools, or other artifacts.

There is little difference between modern feet and the ancient feet that made the footprints, the scientists found. “These are very normal feet,” said Matthew Bennett, a specialist in ancient footprints at Bournemouth and head of the search team. “The toes are well defined.”

The prehistoric feet that left the tracks appear to have been flat, which scientists say may have been caused by a life spent walking barefoot.

As well as giving clues to who made them, the footprints hint at their behavior, showing, for example, whether people were running, carrying a heavy load, or even hunting. “They retain evidence of some really compelling accounts of what might be happening around this time and place in prehistoric times,” Dr Hatala said.

In earlier work published in 2018, scientists described an undated set of fossilized human traces at the White Sands site that they say were made by people stalking a giant sloth. The tracks overlapped those of the sloth, suggesting a chase.

“We’ll never see humans interacting with giant sloths, but footprints tell us sloths were afraid of humans and humans were confident,” said Sally Reynolds, paleontologist in Bournemouth and member of the team. of research.

Scientists have also discovered what they believe are the footprints of a prehistoric woman who walked nearly a mile and a half with a toddler, sometimes carrying the child and sometimes having the youngster walk alongside her. This is the longest fossilized human track ever discovered, according to their research, published in 2018 in the journal Quaternary Science Reviews.

“We found layer after layer upon layer of human imprints, each layer taking us deeper into the past,” said Dr. Reynolds. “It pushes back human occupation of the Americas before the Ice Age. People need to revise their ideas about the first settlement of the Americas.”