This photo provided by researchers shows the Santa Elina excavation site in the Mato Grosso state of Brazil. (Águeda Vilhena Vialou, Denis Vialou via AP)

Researcher Mírian Pacheco holds a round, penny-sized sloth fossil dated to around 27,000 years ago, at the University of São Paulo, Brazil, on Sept 2, 2024, saying that unlike most other specimens, its surface is surprisingly smooth, the edges appear to have been deliberately polished, and there’s a tiny hole near one edge. (AP Photo/Christina Larson)

Thaís Pansani and Kay Behrensmeyer analyze a giant sloth rib bone from central Brazil, in the Smithsonian's National Taphonomy Reference Collection in Washington, D.C. on July 11, 2024. (AP Photo/Mary Conlon)

This combination of illustrations provided by researchers in 2024 shows large animals which once roamed prehistoric North and South America. Top row from left, a glyptodon, a lestodon, and a horse. Bottom row from left, a mastodon, a saber-toothed cat and a toxodon. (Mauro Muyano via AP)

This photo provided by researchers shows prehistoric drawings at the Santa Elina excavation site in the Mato Grosso state of Brazil. (Águeda Vilhena Vialou, Denis Vialou via AP)

This photo provided by researchers shows fossils at the excavation site of Arroyo del Vizcaíno in Uruguay, where researchers have found evidence suggesting human occupation 30,000 years ago. (Martín Batallés via AP)

Thaís Pansani holds a giant sloth rib bone from central Brazil dated to about 13,000 to 15,000 years ago, which is thought to be burned by human-made fire, in the Smithsonian's National Taphonomy Reference Collection in Washington, on July 11, 2024. (AP Photo/Mary Conlon)

Paleontologist Thaís Pansani stands in front the reconstructed skeleton of a giant ground sloth at the Smithsonian National Museum of Natural History in Washington, on July 11, 2024. (AP Photo/Mary Conlon)

This illustration provided by researchers depicts a person carving an osteoderm from a giant sloth in Brazil about 25,000 to 27,000 years ago. (Júlia d'Oliveira via AP)

This image provided by researchers shows an artifact made of bony material from a giant sloth discovered at a rock shelter in Brazil, recovered from archaeological layers dated to 25,000 to 27,000 years ago. (Thaís Pansani, Pierre Gueriau via AP)

This illustration depicts giant sloths, humans and mastodons living alongside one another in central Brazil 27,000 years ago, during the Pleistocene period. (AP/Peter Hamlin)

Thaís Pansani examines giant sloth bones dated to about 25,000 to 27,000 years ago from central Brazil, some of which appear to be burned by human-made fire, at the Smithsonian Institution in Washington, on July 11, 2024. (AP Photo/Mary Conlon)