Molecular dating has shown that several extinct creatures, such as giant sloths and mammoths, survived in South America much later than previously thought, raising questions about the root causes ...

For a long time, scientists believed the first humans to arrive in the Americas soon killed off these giant ground sloths through ... “There’s still a big debate,” Pacheco said.

Sloths were not always slow-moving, furry tree-dwellers. Their prehistoric ancestors were huge — up to four tonnes — and when startled, they brandished immense claws. For a long time ...

SAO PAULO — Sloths weren’t always slow-moving, furry tree-dwellers. Their prehistoric ancestors were huge — up to 4 tons — and when startled, they brandished immense claws. For a long time ...

AP Photo/Mary Conlon Paleontologist Thaís Pansani stands in front the reconstructed skeleton of a giant ground sloth at the Smithsonian ... “There’s still a big debate,” Pacheco said.

Sloths weren't always slow-moving ... as well as similar-aged tracks of giant mammals. But some archaeologists say it's hard to imagine that humans would repeatedly traverse a site and leave no stone ...

New research from several sites is starting to suggest that people came to the Americas earlier — perhaps far earlier — than once thought.

Sloths were not always slow-moving, furry tree-dwellers. Their prehistoric ancestors were huge — up to four tonnes — and when startled, they brandished immense claws. For a long time, scientists ...