REUTERS/Juan Carlos Ulate
A rescued baby sloth rests over a stuffed toy at the Sloth Sanctuary in Cahuita de Limon August 25, 2010. The center shelters over 100 orphaned and injured sloths
Sloths are notoriously slow. Living in rainforests in Central and South America, sloths spend most of their time hanging upside down in the trees, rarely coming down to the ground.
There are two main families of sloths, two-toed sloths, and three-toed sloths, and they all share something in common: They've been around for millions of years - 64 million, to be exact.
For comparison, modern humans have only been around for about 200,000 years.
Sloths slowness, as it turns out, is the key to their survival. Far from being lazy, sloths are actually really efficient at conserving energy, and it all has to do with their diet.