Limestone mesas dominate the foreground, the pale strata angling skyward above what, even by West Texas standards, is a rough dirt road. Above the mesas, higher still, is the Sierra Vieja, red ...

A hidden source of Ice Age history has turned up at a water-filled cave in Texas, where a paleontologist discovered dozens of ancient fossils. Water caves throughout the state, home to active ...

Deep in the unyielding darkness of a Brazilian cave, a pale, blind, spiny beast carefully feels its way across rust-colored rocks. Meet Paleotoca diminas, a spider new to science. The species, ...

The Smithsonian's National Zoo is home to three Linnaeus's two-toed sloths and shares some sloth basics, but here are three lesser-known sloth facts. 1. The Smithsonian has a collection of fossilized ...

Scientists report new evidence that some 5,000 years ago, a sloth smaller than a black bear roamed the forest floor of what is now the Dominican Republic in the Caribbean Sea, living a lowland life ...

Scientists have analyzed ancient DNA and compared more than 400 fossils from 17 natural history museums to figure out how and why extinct sloths got so big. Most of us are familiar sloths, the ...

More than 11,000 years ago, young children trekking with their families through what is now White Sands National Park in New Mexico discovered the stuff of childhood dreams: muddy puddles made from ...