What is a Sloth?

Tricia Christensen
Tricia Christensen

A sloth is an arboreal mammal indigenous to the South American Rainforests. The name has come to suggest laziness or slowness, and it is rooted in the easy, slow-moving lifestyle of this animal. It is very slow and deliberate in its movements, living upside down in rainforest trees for most of its life. The digestive system of this animal is also slow, and a traditional meal of leaves may take as much as a month to completely digest.

The name sloth has come to suggest laziness or slowness.
The name sloth has come to suggest laziness or slowness.

The modern sloth is relatively small in size, and most are approximately 2 feet (0.61 m) long. They may weigh around 9 pounds (roughly 4 kg). They have small eyes and ears, and only some varieties have tails. Their brown or grey coats are fuller toward the head and upper body, and they have an undercoat of dense fur. Average life expectancy in the wild ranges between 10 and 20 years, while an animal in captivity may live up to 40 years.

Sloths are identified as having either two or three toes.
Sloths are identified as having either two or three toes.

The prehistoric ancestor of this animal is the Giant Ground Sloth, Megatherium, which may have been as large as the modern elephant. Unlike modern sloths, it was not arboreal, and its size made it virtually invulnerable to predators. Past studies suggest the saber-toothed tiger might have preyed on this animal, but most scientists now dismiss this suggestion. It was simply too large and could counter an attack viciously if necessary.

Like its prehistoric ancestors, today’s sloths are mostly herbivores. They occasionally eat small insects and lizards, but in general, their digestive system is ideally suited to consuming leaves from rainforest trees. These animals seldom descend from their arboreal homes because they do not need to drink water; they get as much hydration as they need from leaf consumption.

The leaves sloths consume are not easy to digest, and do not provide much in the way of energy, leading to the animals' slow movement. Their stomachs have several compartments, loaded with tiny bacteria that help break down the cellulose of leaves, yet their metabolism remains sluggish. Most sleep up to two-thirds of the day and maintain a very low body temperature.

There are several species of sloth, which can be classed as either two-toed or three-toed, a somewhat misleading classification. Both classes have three toes on their back feet, but the two-toed varieties have two fingers on their front hands or paws. Three-toed animals are slightly larger than their two-toed cousins, but the two-toed varieties are a bit faster moving.

When cornered by a predator, such as the harpy eagle or the jaguar, a sloth can be quick, using its long claws to discourage attacks. It is often successful in defending itself, and most animal deaths are due not to predators, but to electrocution from contact with electric wires.

Though the rainforest is diminishing, only one species, the Maned Three-Toed Sloth, is considered endangered at this time. Further destruction of the rainforest will likely result in endangered classification for the other four species. These animals have adapted to human encroachment on their territory, however, and since they do not pose a threat to humans, they are usually left alone.

Sloth spend most their time in the trees of rainforests.
Sloth spend most their time in the trees of rainforests.
Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent wiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments


Wow, giant ground sloths were real? I had heard of them, but I always thought they were just some made-up animal for movies and stuff. Very interesting.

Did they just eat leaves and stuff, too? Were they around with the dinosaurs or did they come about later on? I'm really interested in hearing more about them now.


@jmc88 - I was thinking the same thing as you about them not having much muscle. I'd be curious to know whether they do or not. Think about it, they are hanging from tree limbs all day. It seems to me like that would take a lot of energy to do. A human couldn't hang upside down like that for an extended period of time. A sloth can sleep like that!

I hadn't heard the bit of trivia about sloths not needing to drink. I remember two interesting facts about sloths. Since they move so slowly, moss starts to grow on their fur after a while. Also, they only come down from the trees to defecate, and they always do it in the same spot. No one knows why.


@matthewc23 - I am with you as far as being more interested in sloths than some other creatures. I think it has to do with the combination of them looking so interesting and being so much different than every other animal that makes them endearing.

I mean, think about it. How many other animals are there that survive by being so slow? Everything else either tries to be fast or strong or camouflaged in some way, but not the sloth. It's fascinating to me that they don't have more predators, since they would be so easy for a big cat to catch.

I am guessing part of it is that their diet probably means that they don't have much nutritional value. Since they don't move much, they probably don't have much muscle to supplement the kind of diet a bigger animal would need. I've never seen them attack anything, but I'm guessing sloth toes and claws are pretty sharp.


I absolutely love sloths. They always remind me of Chewbacca from Star Wars. I remember being in grade school watching movies about the rainforest where they would show sloth pictures. For whatever reason, I always thought they were more interesting than the "exciting" animals like monkeys and jaguars.

We even had to write a report about a jungle animals in one grade, and I chose the sloth. I had forgotten about a lot of the facts that were mentioned here, though. I hadn't heard about them being electrocuted. That is too bad.

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