Stone tools unearthed in a cave in central Mexico and other evidence from 42 remote archaeological sites suggest humans arrived in North America – a milestone in human history – earlier than was known before, about 30,000 years ago.
Scientists said they had found 1,930 limestone tools, including small pieces and fine blades that could be used to cut meat and small points that could be used as spearheads, indicating the presence of humans at the Chiquihuite cave in a mountainous region of Mexico’s Zacatecas state.
Archaeologist Ciprian Ardelean of the Universidad Autónoma de Zacatecas in Mexico, lead author of one of the two studies published in the journal Nature, says the tools are between 31,000 and 12,500 years old. The site has been periodically occupied for millennia by nomadic hunter-gatherers.
In the second study, evidence from 42 sites around North America and the location of a land bridge connecting Siberia with Alaska during the last Ice Age suggests a human presence dating back to at least during the period known as the Last Glacial Maximum, when ice sheets covered most of the continent, about 26,000 to 19,000 years ago and shortly after.
The study also concerns humans about the extinction of many large mammals during the Ice Age such as mammoths and camels.
Our species first appeared about 300,000 years ago in Africa, later spreading worldwide. The new findings contradict the conventional view that the first people arrived in the Americas around 13,000 years ago, crossing the land bridge, and were associated with the “Clovis culture,” known for distinctive stone tools.
Some of the stone tools were found to be more than 30,000 years old
The findings suggest that a lower number of people entered the continent earlier than previously understood – some probably sailed along the Pacific coastal route rather than across the land bridge – and some died without leaving any descendants.
Archaeological scientist Lorena Becerra-Valdivia of the University of Oxford in the UK and the University of New South Wales in Australia said the continent’s population then expanded dramatically starting around 14,700 years ago.
“The process of colonizing the United States was a complex, complex and multifaceted process,” Ardelean said.
“These are model-shifting results that help us understand the early dispersal of modern humans to the Americas,” adds Becerra-Valdivia.