Ancient footprints give surprising new clues about the first Americans

At the height of the last ice age, generations of children and adolescents roamed barefoot along a muddy lake in what is now New Mexico, crossing paths with mammoths, giant ground sloths, and an extinct dog species known as dire wolves. Is known.

Now, some 23,000 years later, the fossilized footprints of young people are providing new insight into when humans first populated the Americas. Discovered in White Sands National Park by a research team that began its work in 2016, the track is about 10,000 years old and about 1,600 miles farther than any other human footprints known in the US, scientists reported Thursday in the Journal. Told in Science.

During the last ice age, “in my view, this is the first clear evidence of a human presence in the Americas”, said Daniel Odes, head of science and research at the US National Park Service and a senior author of the report. Search. “Footprints are undoubtedly human.”

For decades, many scientists were convinced that humans first arrived in the Americas 13,000 years ago, on a journey from humanity’s African homeland to Asia or the continent after crossing an ice-free land bridge from the sea along the Pacific coast. Arrive. Others argued that they came 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 the newly found footprints suggest that humans lived in the American Southwest in an era when massive ice sheets closed the way for migrants from Asia to the New World, researchers say. said.

“It certainly gives a really strong boost to the argument that humans were living in North America at this time, much earlier than previously thought,” said Kevin Hutla, a paleontologist at Chatham University in Pittsburgh who studied human walking. studies development. “If the dating continues, it adds to this growing body of evidence that humans are in North America during this period.” He was not involved in the search.

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

Under most circumstances, fossil footprints are impossible to date precisely. But these were intertwined with sediment containing the seeds of aquatic plants that once flourished along the lake. Radiocarbon dating of the plants showed that the footprints were between 21,000 years and 23,000 years old.

The scientists said the footprints represent 10 to 15 individuals and were laid mostly by children and adolescents over a period of 2,000 years. No one knows who pulled the people to the spot. So far, no sign of a campfire, equipment or other artifacts has been found.

The scientists found that there is little difference between modern feet and the ancient feet that made up the footprints. “They are very normal feet,” said Matthew Bennett, an expert in ancient footprints at Bournemouth and leader of the research team. “The toes are well defined.”

The prehistoric feet that left the tracks appear to be flat, which scientists have said may have been caused by walking barefoot throughout life.

In addition to providing clues about the people who built them, footprints hint at their behavior, for example, whether people were running, carrying heavy loads, or even hunting. “They are preserving the evidence of truly compelling narratives about what is happening at this time and place in prehistory,” Dr. Hatla said.

In earlier work published in 2018, scientists described an undated set of fossil human tracks at the White Sands site, which they believe were made by people chasing a giant sloth. The tracks overlapped those of the sloths, suggesting a chase.

Sally Reynolds, a Bournemouth paleontologist and a member of the research team, said, “We will never see humans interacting with giant sloths, but the footprints are telling us that sloths were afraid of humans and humans were confident. “

Scientists also uncovered what they believe to be the footprints of a prehistoric woman who traveled about a mile with a baby, sometimes carrying the baby and sometimes walking the young by her side. It is the longest fossil human trackway ever discovered, according to their research, which was published in 2018 in the journal Quaternary Science Reviews.

“We have found layer after layer of human footprints, each layer taking us deeper into the past,” Dr Reynolds said. “It’s pushing back the human occupation of America before the Ice Age. People are having to revise their views of the first peoples of America.”