Three small bone fragments from a giant sloth, one of the fascinating animal species that reigned during the Pleistocene, could compel us to reconsider many certainties about human presence in the Americas. Until recently, there was some consensus that Homo sapiens entered the Americas about 15,000 years ago from Eurasia via what is now the Bering Strait between Russia and Alaska. But just a few days ago, two Brazilian researchers published a study showing that in a corner of central Brazil there were people polishing sloth bones at least 25,000 years ago and using them to make what is perhaps America’s oldest jewelry.
The authors of the discovery are archaeologist Mirian Liza Alves Forancelli Pacheco and paleontologist Thais Rabito Pansani from the Federal University of São Carlos, who published the result of years of work in the British journal Proceedings of the Royal Society B. For years they worked on pieces of bone, “artifacts,” they say, small, somewhat triangular, and very mysterious. The truth is that they were found 28 years ago at the Santa Elina site in west-central Brazil, where there are also numerous cave paintings. In all that time, several things have been discovered, such as the skeletal remains of giant sloths that lived in the area between 27,000 and 25,000 years ago. It was also known that the holes were not the work of natural erosion, but that there was a human hand behind them. They were a deliberate craft work. The big question was: did humans and sloths coincide in time? Or were people working on a fossilized animal that had been buried there for thousands of years?
Giant sloth bone artifacts found in Santa Elina, west-central Brazil. Thais Pansani and Pierre Gueriau (Courtesy)Thais Pansani and Pierre Gueriau (Courtesy)Thais Pansani and Pierre Gueriau (Courtesy)
The answer would be crucial in dating man’s presence in the region. To answer the million-dollar question, Pacheco decided to tackle the problem with a multidisciplinary team of archaeologists, paleontologists, chemists and engineers, he explained in a phone interview. Their complementary knowledge, together with electron microscopy and photoluminescence techniques, provided clear results: “We saw that the polish was very uniform, which means that the carcass was fresh and that the bones had been gnawed by mice.” The bones were fashioned into objects when the animal was dead for a short time. Mice, greedy for organic matter, would not have gone in search of a bone in an advanced fossilization process.
The researchers also concluded that they were artifacts for personal use. It was probably jewelry, there are marks in one of the holes indicating it was hung as one side is more worn than the other. Yes, its use is a mystery. “It can be symbolic or ritualistic, but it’s hard to say,” admits the archaeologist, who doesn’t feel comfortable talking about jewelry. Better to stick with the less attractive but more cautious term “artifacts”. The three small bones tell a lot about human interaction with Ice Age megafauna and are not unique, according to paleontologist Brito, who enthusiastically accepted the challenge of unraveling the mystery.
Rock paintings in Santa Elina. Agueda and Dennis Vialou (Courtesy)
The expert first likes to remember which animal it is: a corpulent mammal weighing up to 500 kilograms, which walked on all fours and could reach a height of up to six meters when standing. It was essentially a herbivore, although it had a powerful jaw and strong claws. One of its distinctive features is that, unlike today’s sloths, it had a kind of bony shell under its skin, hard plates similar to those of armadillos. These pieces are the osteoderms, the material from which the men of their day made handicrafts. About 11,000 years ago, giant sloths disappeared from America, but their fossil remains abound. There is growing evidence of the relationship between humans and these giant animals, and there is even talk of their possible role in their extinction. In addition, older and older remains are emerging. Huge sloth bones with cut marks dating back 30,000 years have been found in Uruguay, and even footprints of this animal interspersed with human footprints in New Mexico, USA, which may be around 23,000 years old. For this reason, the researchers from Brazil emphasize that their discovery is not an isolated case, but another weighty piece of evidence that forces us to reconsider chronologies.
It’s not an easy task. There is still reluctance in academia to embrace the theory of early settlement. “More are emerging, but when these ancient dates emerge, some researchers are skeptical, doubting the human presence on the continent at such an ancient time.” “Scientifically, the debate is always welcome, but there are many that are simply rooted in dogma,” laments the paleontologist. Pacheco, his partner, goes a step further and speaks of an “ethnocentric movement” that allows certain explanations only if they come from the north. In any case, these two researchers do not want to give up their fight to prove that humans arrived in America much earlier than assumed. “A lot is still to come. Santa Elina has a lot of potential and although the excavations have stopped, we are already thinking about returning,” warns Pansani. For the time being, the three artifacts remain well guarded in the warehouses of the University of São Paulo Museum (USP), away from the eyes of visitors.
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