• Mammoth remains found in 2013 in New Mexico suggest humans settled in North America about 37,000 years ago.
  • The discovery means humans might have been in North America 20,000 years before scientists previously thought.
  • The fossils were recovered from what appeared to be an ancient butchering area, where bones looked “deliberately broken” by blunt-force fractures.

​​​One of the most common beliefs among researchers is that humans first settled in North America 16,000 years ago. But according to a recent fossil find, that may not be true.

In 2013, a tusk was found in New Mexico, as well as a bashed-in mammoth skull and other bones that looked “deliberately broken” and had blunt-force fractures. Carbon dating analysis suggests the pieces are roughly 37,000 years old, a discovery that could have significant implications in tracing humans’ earliest existence in the Americas.

The area where the remains were found is an ancient butchering site where humans appeared to process their kills, although it’s hard to determine what was done by humans and what was done naturally, said researchers at the University of Texas at Austin. Researchers also found rodent teeth and the remains of birds, fish, snails and a a lizard at the site.

Earlier research led scientists to believe the first humans that settled in North America belonged to the Clovis culture, who left behind stone-wrought tools 16,000 years ago.

But carbon dating analysis on collagen extracted from the mammoth bones date the butchering site at 36,250 to 38,900 years old. That means it’s the oldest known site left behind by ancient humans in North America.

The peer-reviewed findings were published in July in Frontiers in Ecology and Evolution.

But that’s not the only interesting thing about the discovery, said Timothy Rowe, a professor at the University of Texas at Austin’s Jackson School of Geosciences.

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Bone blades, hammer stones show how ‘thorough’ these early humans were

The early humans who used the butchering site shaped bones into blades to break down the animals’ carcasses, according to Rowe. There are also signs they rendered the animals’ fat over a fire.

“The real evidence that we have has to do with the breakage patterns, and how thorough they are,” he told USA TODAY. “They must have used rocks or hammer stones to bust the skeleton apart. … These people would use whatever they could. This site indicates that humans attained a global distribution a long time ago, much earlier than once thought.”

A close up of a bone pile during excavation in New Mexico. This random mix of ribs, broken cranial bones, a molar, bone fragments, and stone cobbles is a refuse pile from the butchered mammoths. It was preserved beneath the adult mammoth’s skull and tusks.

How were humans able to kill and process such large animals?

Rowe said the humans responsible for slaying the mammoths could have been hunter-gatherers.

The adults were likely busy breaking down the mammoths’ body parts, which is a pretty involved process. They probably skinned them, used their bones to make tools and broke other bones into small pieces and boiled them to extract grease, he said.

The children, if they were present, probably were out catching fish and learning to catch lizards and birds, he said.

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He also said there are a couple of ways they ended up with the mammoths. They may have come across the animals once they had already died, or they ambushed the mammoths, or the animals may have been startled and ran over the edge of a cliff.