Imagine a sloth. You probably picture a medium-sized, tree-dwelling creature hanging from a branch. Today's sloths—commonly featured on children's backpacks, stationery and lunch boxes—are slow-moving ...

Paleontologist Thaís Pansani standing in front of a reconstructed giant ground sloth skeleton at the Smithsonian National Museum of Natural History. AP SAO PAULO (Associated Press) — Sloths weren’t ...

For years, paleontologists debated the timeline for recovery following the devastating end-Permian mass extinction (the ...

A fossil skull of a prehistoric amphibian, found in a 230-million-year-old burrow in Wyoming, turned out to be from an unknown species. David Lovelace In prehistoric times, western Wyoming was a land ...

A 161 million-year-old fossil, linked to a line of extinct frog-like amphibians, is the oldest tadpole ever found. By Asher Elbein The metamorphosis of a frog from baby to adult is one of nature’s ...

A fossilized skull of a massive amphibian has been discovered in a Texas quarry, and its appearance has sparked comparisons to an animated character from a beloved children’s film. Though the ...