To time how fast a sprinter runs, you just need a stopwatch. To time how fast magma moves, you need to know a little bit ...

Some of the most tantalizing clues come from an archaeological site ... researcher Mírian Pacheco holds in her palm a round, penny-sized sloth fossil. She notes that its surface is surprisingly ...

Sloth Crossing is the newest exhibit at the Jacksonville Zoo and Gardens. The zoo is home to a pair of sloths, Chata and Ruth. The new exhibit will be in the zoo's Play Park area. Two sloths ...

The Hoffman's two-toed sloth is one of the world's slowest mammals—so sedentary that algae grows on its furry coat. The plant gives it a greenish tint that is useful camouflage in the trees of ...

The sloth in the video above appears to be an adult pale-throated three-toed sloth, or Bradypus tridactylus. Their native habitat is the canopies of tropical rainforests in Central and South America.