heyYour species started migrating out of Africa 100,000 years ago. Apart from Antarctica, the Americas were the last continents reached by humans, with early pioneers crossing the now-submerged Bering land bridge that once connected Eastern Siberia to North America.
Sometime during the Pleistocene ice age, which ended 10,000 years ago, large ice sheets covered much of Europe and North America. The water locked in these ice sheets lowered the sea level, allowing people to walk across the bridge from Asia through the Arctic to Alaska. But during the peak of the last glacial cycle, their path south into the Americas was blocked by a continental-wide ice sheet.
Until now, scientists believed that humans only traveled south to the Americas when this ice barrier began to melt—at first, 16,500 years ago. But with our partners, we have discovered A group of fossil footprints that suggest humans set foot on the continent thousands of years ago.
These footprints, discovered in New Mexico’s White Sands National Park, were made by a group of juveniles, children, and sometimes adults, and have been dated to the last glacial maximum height of about 23,000 years ago. This makes them potentially the oldest evidence of our species in the Americas.
Our findings support the idea that humans were present in the southern part of North America before the last glacial peak – a theory based on hitherto disputed and potentially unreliable evidence.
There are literally thousands of fossil footprints in White Sands. together tell stories How prehistoric humans interacted with extinct Ice Age megafauna, such as the Colombian mammoth and giant ground sloth.
The tracks were deposited on the margins of a large wetland – perhaps a lake after the rainy season, but sometimes like a patchwork of water bodies. Till now the problem was dating these footprints. We knew they were imprinted before the extinction of the megafauna, but not exactly when.
This changed in September 2019 when the team found tracks with undisturbed sediment above and below them. Within that sediment were layers containing hundreds of seeds of common trench grass. Rupiah Sirosa. These seeds, when radiocarbon dated, will reveal the age of the footprints themselves. The analysis revealed the age of the seed to be 21,000 to 23,000 years old, suggesting that humans visited the site repeatedly over at least two millennia.
The White Sands footprints provide clear evidence that people were at the last glacial maximum in the Americas, and not sometime later, as previously thought. This is a big deal for our understanding of the genetic structure of the peoples of the Americas and of Indigenous Americans.
Using the DNA of modern Indigenous Americans, scientists have discovered that their ancestors arrived from Asia in several waves, some of which became genetically distinct. The reason for this separation is not clear. Now, our new footprint evidence provides an explanation, suggesting that the early Americans were isolated south of the North American ice sheet, only to join others when that sheet melted.
Our discovery may reopen speculation about other archaeological sites in the Americas. is one of them Chiquihuit Cave in Mexico. Archaeologists have recently claimed that evidence from this cave suggests that humans occupied the Americas about 30,000 years ago – 7,000 years before people left White Sands footprints.
But the Chiquihuite Cave findings are disputed by some, as stone tools can be difficult to interpret and tool-like stones may have formed through natural processes. Stone tools can also move between layers of sediment and rock. Fossil footprints cannot. They are fixed to a bed floor, and therefore provide more reliable evidence of when humans released them.
We see our ancestors engaged in life-death struggles – forced to fight the elements only to survive. Yet evidence from White Sands indicates a playful, relatively relaxed setting, in which teens and children spend time together in a group.
It’s probably not that surprising. Children and adolescents are more energetic and playful than adults and therefore leave more traces. Adults are more economical in their movement, leaving less track.
But another interpretation of this new footprint evidence is that juveniles were part of the workforce in these early bands of hunter-gatherers. It is possible that the tracks were left by young men who brought in and carried resources to their prehistoric parents.
In any case, those who left their track on White Sands were the earliest known American teens. Set in stone, their footprints pay homage to their ancestors, who walked the long land bridge over the Americas millennia before what we now know was commonly believed.
Matthew Robert Bennett is Professor of Environmental and Geographical Sciences at Bournemouth University. Sally Christine Reynolds is a leading academic in hominin palaeontology at Bournemouth University. This article first appeared on Conversation
Credit: www.independent.co.uk /