Some of the most tantalizing clues come from an archaeological site in central Brazil called Santa Elina, where bones of giant ground sloths show ... crossing the Bering land bridge from Asia.

Paleontologist Thaís Pansani standing in front of a reconstructed giant ground sloth skeleton at the Smithsonian ... continent after crossing the Bering land bridge from Asia.

Paleontologist Thaís Pansani stands in front the reconstructed skeleton of a giant ground sloth at the Smithsonian National Museum of Natural History in Washington. (Picture credit: AP ...

For a long time, scientists believed the first humans to arrive in the Americas soon killed off these giant ground sloths through hunting ... crossing the Bering land bridge from Asia.

Thais Pansani and Kay Behrensmeyer analyse a giant sloth rib bone from central Brazil ... into the continent after crossing the Bering land bridge from Asia. And because the fossil record shows ...