Humans May Have Arrived in the Americas Earlier Than Previously Thought

Researchers say that humans coexisted with giant sloths in Brazil some 25,0000 years ago

Bone amulet
Scientists found that carvings on the bones of giant sloths were made within a few years of the animals' deaths. Thaís Pansani

About 30 years ago, three artifacts made from the bones of giant sloths were unearthed in Brazil—and until recently, they hadn’t been studied extensively.

Now, researchers say that the bones are pendants: Humans likely polished them and drilled small holes into them, intending to wear them as prehistoric fashion accessories, according to a study published this week in the journal Proceedings of the Royal Society.

Dating to between 25,000 and 27,000 years ago, the pendants are the oldest known personal ornaments unearthed in the Americas, reports CNN’s Katie Hunt. They also support the theory that humans inhabited South America far earlier than previously thought.

“We now have good evidence—together with other sites from South and North America—that we have to rethink our ideas about the migration of humans to the Americas,” says study co-author Mirian Liza Alves Forancelli Pacheco, an archaeologist at the Federal University of São Carlos in Brazil, to Christina Larson of the Associated Press (AP).

Bone 2
The amulets were made from the armadillo-like protective plates under the fur of giant sloths. Thaís Pansani

Based on markings on the sloth bones, scientists concluded that humans—rather than other animals—very likely drilled the holes into the bones.

Additionally, the new research suggests that they crafted the pendants soon after the sloths died, which means that the humans and sloths coexisted.

At 10 to 13 feet long, giant sloths weighed over 1,000 pounds. Their bodies were protected by armadillo-like plates under their fur, and it was these plates that humans drilled holes into—“as if they had been designed to be threaded on a string,” says Pacheco to the New York Times’ Franz Lidz.

For many decades, scientists thought that humans reached the Americas via a land bridge between Russia and Alaska around 15,000 years ago. Now, the new study joins a growing body of work that suggests an earlier arrival date. In 2021, for example, researchers announced that they had found fossilized human footprints in New Mexico that were between 21,000 and 23,000 years old. The new study moves that timeline even earlier.

The timeline is constantly debated, and some scientists dispute the dates connected to certain finds, per the AP. But lead author Thaís Pansani, a paleontologist at the Federal University of São Carlos, is optimistic, telling Kristina Killgrove of Live Science that many sites in South America have yet to be studied.

“We believe that there should be more evidence waiting to be found in the rock shelters and caves of Brazil in places little or not explored,” Pansani says.

Many other researchers are also optimistic about the new study—and what its findings might mean.

“This is a really significant study because it adds to a growing body of data on the antiquity of human occupation in the Americas,” April Nowell, a Paleolithic archaeologist at the University of Victoria in Canada who was not involved in the study, tells the Times. “It also shows the importance of personal ornaments.”

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