Central and South America


Tropical forests and cloud forests

“Leaf it” to the sloth

Thousands of years ago, large ground sloths roamed the US. They ranged in size from an average-size dog to that of an elephant. These ground sloths had long claws and ate plants. They became extinct about 10,000 years ago. Present-day sloths are much smaller, live in trees, and are related to anteaters.

I’m a sloth

In a nutshell, sloths are slow-moving, solitary, arboreal, forest-dwelling, and nocturnal herbivores, found in tropical forests and cloud forests in Central and South America. Their sharp claws are 3 to 4 inches (8 to 10 centimeters) long—handy for hanging onto tree branches but making walking on the ground quite awkward.

However, sloths are great swimmers and can drop from a tree into a river to swim across it while doing the breaststroke! When sleeping, sloths often curl up in a ball in the fork of a tree.

Sloths have grooved hair that allows algae to grow there, giving them a green tint that provides camouflage in the forest. Sloths can nibble on the algae for added "greens."
The two-toed sloth does everything while hanging upside down from trees, including eating, sleeping, mating, and even giving birth. The only time it comes to the ground is to poop and pee, which it does once a week.
With their low-energy diet of leaves and occasional fruit, sloths move slowly and sleep 15 hours a day to conserve energy.
Sloths have a powerful grip: their long claws curve around tree branches like a safety harness. Even after a sloth dies, it sometimes remains hanging in the trees with its death grip.

A young Linnaeus’s two-toed sloth is being trained as an animal ambassador. Her parents currently live in the Zoo’s Elephant Odyssey.

Though fairly common in their natural habitat, deforestation and other forms of habitat destruction and hunting remain threats for the sloth. Other human-made threats include power lines and roads. Educating children and adults in the sloths’ home countries about the animals' importance to the ecosystem and how to treat the animals respectfully remains a challenge for those who want to help this unique and wonderful animal.

Both two-toed sloth species have been bred and successfully maintained in zoos. However, species identification between the two has always been problematic, as they look much alike, representing an obstacle to managed-care breeding programs. Based on the genetic information, a senior research associate in our Genetics Division designed a low-cost, easy to-use genetic tool to identify two-toed sloths and improve management of the captive population. This tool allows visualizing DNA differences between species in a polymer matrix, a procedure that can be implemented with non-sophisticated tools in simple laboratory settings. Read more here...

You can help us bring sloths and other species back from the brink by supporting the San Diego Zoo Global Wildlife Conservancy. Together we can save and protect wildlife around the globe.