(Choloepus didactylus)


Two-toed Sloths spend so much time hanging around sleeping that they actually grow algae in their hair. The resulting greenish color helps camouflage the sloth from predators as he makes his slow way through the rainforest canopy.

If you notice a big furry lump tucked into the trees in our Cloud Forest exhibit, don't worry -- it's  not a monkey, or a bear, or some weird kind of hairy fruit.  That's just Wookie, our Linnaeus's Two-toed Sloth.

As you might guess from the name, Two-toed Sloths have only two toes on their front feet (there are also three-toed sloths).  Each of these toes is equipped with long, curving claws that help the sloth hang from branches high above the rainforest floor.  In fact everything about a sloth is built for hanging.  Sloths spend almost their entire lives upside down -- eating, mating, and even giving birth upside down.  When a sloth does end up on the ground (they climb down every week or so to defecate), they are essentially defenseless.  Their hind feet aren't built for walking, so they have to drag themselves along the ground using their front legs.  If caught on the ground by a predator, sloths will defend themselves with those powerful claws.  Sloths can be surprisingly fast -- when necessary.

The rest of the time, though, a sloth's life pretty much consists of eating and sleeping.  Lots of sleeping.  Up to fifteen hours a day of sleeping.  But don't make the mistake of thinking the sloth is lazy.  It's just very good at conserving energy.  A sloth's diet of leaves, shoots, and bark isn't very nutritious.  To compensate, he has a large, multi-chambered stomach that holds huge quantities of food which the sloth chews for a long, long time before swallowing (to maximize digestibility).  Even so, it can take up to a month for a sloth to digest one meal.  With so much effort required just to get nutrition from his diet, is it any wonder the sloth doesn't move around any more than absolutely necessary?

The Two-toed Sloth has the lowest and most variable body temperature of any mammal, due in part to the fact that sloths can't shiver to keep warm.  Depending on the weather, a sloth's temperature can range from 74 - 92 degrees F.  If a sloth's body temperature drops too low, the bacteria in its gut that helps it digest food can stop working, and the sloth can starve to death even with a full stomach.

As with many rainforest creatures, both Two-toed and Three-toed Sloths are threatened by destruction of their habitat.  One and a half acres of rainforest is lost every second to logging and burning.  Where rainforests once covered nearly 40% of the earth's surface, they now make up only 6%, with experts fearing even that could be gone in the next 40 years.  The fragmentation of rainforest habitat means sloths must come down to the ground in order to drag themselves from tree to tree in order to get enough to eat.  This leaves them vulnerable to predation by jaguars, ocelots, and domestic dogs, as well as automobiles when they try to cross roadways.

So the next time you recycle an aluminum can, or print on both sides of the paper to reduce how much you use, or enjoy sustainably harvest nuts and chocolate, be happy knowing that you're helping sloths like Wookie.  That little smile on his face while he's napping is just his slothy way of saying, "Thank you for caring!"


Central America and northern South America.




A variety of plants, fruits, and leaves.


Two-toed Sloths are pregnant for about six months. They give birth to a single offspring, who spends the first five weeks of its life hanging onto mom while she moves through the rainforest in search of food. Young will stay with their mother for up to two years.


Not Under Threat (Least Concern)

At the Aviary

See Wookiee the Two-Toed Sloth in our Cloud Forest exhibit.