First South Americans Ate Giant Sloths

Giant sloths were eaten by a population living in Uruguay 30,000 years ago, suggesting humans arrived in the Americas far earlier than previously thought, according to a new study.

The discovery, along with other recent findings, strengthens the theory that people arrived in South America via ocean crossings long before humans might have walked into North America from northeastern Asia, during the end of the last glacial period around 16,000 years ago. The study was published in the latest Proceedings of the Royal Society B.

These brave individuals apparently did not shy away from big game either, with giant sloth being at the top of the menu.

"If our interpretation is correct and the sloths were consumed, they might have been an interesting source of meat because of their very large size," lead author Richard Fariña told Discovery News. Giant sloths could grow to 15 feet and are estimated to have weighed between 2-4 tons.

Fariña, a paleontologist at the University of the Republic in Uruguay, and his team analyzed over 1,000 bones excavated at a site called Arroyo del Vizcaíno near Sauce, Uruguay. The bones belonged to at least 27 individuals, mostly from the giant sloth Lestodon. Radiocarbon dating suggest the site and bones date to 30,000 years ago.

The researchers determined that several of the giant sloth bones feature deep, asymmetrical marks consistent with those produced by human stone tools.

A stone, shaped like a scraper tool and found at the site, shows signs of wear from probable use by humans, according to Fariña.

He added that there is no evidence that the bones were part of a river deposit or some other nature-made collection.

Virtually all of the bones belonged to large, meaty adult giant sloths, which again suggests human may have been eating them. A natural collection of sloth bones likely would have included individuals representing multiple age groups.

When the sloths were alive, the landscape would have featured a "stream going through gently rolling grasslands," he said. The site today is somewhat similar.

Just last month, another team of researchers in nearby Brazil brought together artifacts -- including cave paintings and ceramic art -- from Serra da Capivara national park in Brazil's northeastern Piaui state. The oldest artifacts date to 30,000 years ago.

Franco-Brazilian archaeologist Niéde Guidon, who worked on the project and has led explorations of Piaui's interior, said that, in light of the findings from Uruguay and Brazil, she believes that it is time to reconsider how and when the Americas were first populated.

Piecing together the latest evidence, she believes that humans came to South America at least 30,000 years ago, and possibly much earlier, by water.

"130,000 years before the present, Africa suffered from a very dry climate, which was the origin of the deserts (there)," she said. "People tried to find food in the sea, and the streams and winds (flow) from Africa to the northeast of Brazil. It is possible to think that some boats arrived at the coast of Piaui."

To this day, these same water and wind currents benefit cruise ships coming into Brazil.

The indigenous people from Piaui and surrounding regions had ancestors with "dark skin (and) their hair was black, but smooth and not curly," Guidon said.

Visitors to Uruguay will soon be able to see the Arroyo del Vizcaíno artifacts.

A recreation shows a giant sloth, which could grow to 15 feet and weigh 2-4 tons.

Sloths are so photogenic that they have been recruited to serve as animal ambassadors for Suriname, a country in northern South America. The laid back animals are also helping out The Guiana Shield, a tropical wilderness region known as The Guiana Shield.

Rebecca Field, video production manager at Conservation International, made this effort possible by traveling to Green Heritage Fund Suriname, which is essentially a sloth orphanage run by Monique Pool.

Field said, "When we arrived at her house, we quickly became 'slothified' -- a term Monique came up with to describe her situation. It means "overwhelmed by sloth."

Sloth in a bowl, anyone?

Life was not always so happy for this little guy. Kevin Connor, media manager for Conservation International, told Discovery News that sloths like this, before their rescue by Pool, "had gradually been migrating into one forest patch, an undeveloped area of the city that was finally being cut down."

When exposed to human kindness, the natural friendliness and curiosity of sloths often is evident. Here, the sloth looks to be reaching out to the viewer, but this would have really been the photographer, Becca Field.

Sloths frequently form bonds with humans. Like primates, sloths will sometimes cling to humans similar to the way that infants do.

Russ Mittermeier, seen here, is the president of Conservation International. He and others are interested in Suriname. Connor explained its importance. "This country, roughly the size of Florida, contains 25 percent of the world's remaining intact forest."

The word "sloth" is synonymous with laziness, but these animals are just conserving precious energy reserves when they lounge around like this.

Leaves are their main source of nutrition, but leaves provide little energy and can be difficult to digest.

This sloth seems to be looking at the camera, but it is likely interacting with Field.

She said, "Since the day I first laid eyes on a sloth, I have been obsessed. How could I not be? They're adorable, gentle, slow-moving creatures with irresistible smiles."

As an ambassador for Suriname, helping to draw attention to the nation's wildlife, this individual has much to be proud of, as evident in this photo. Connor explained, "Monique's organization, along with CI, is working to show the value that these animals have as a tourist attraction in order to get them their own park in the region."

"Sloths -- being, in my opinion, the cutest of all forest dwellers -- make great ambassadors for the forests of the Guiana Shield," Field said. "Like all of us, they depend on the forest to survive and thrive. They spend virtually all their time in the treetops -- eating, sleeping and even giving birth in the trees. The more time I spent with them, the more I learned firsthand why it is so important we conserve areas like the Guiana Shield."

Sloths seem to love positive attention and will respond with all sorts of cute poses. Here an individual tilts its head affectionately for Field.

"The forests might be homes to the sloths, but they also provide us with many of the things we need to survive and thrive: clean air, fresh water, a stable climate and countless other benefits, both mental and physical," Field said. "Together, with the sloths as our inspiration, we can help conserve what is important to us all."