Sloths move slowly. Some people think sloths are slow because they are lazy. That is not the real reason. Sloths live in trees, high up in the rainforest canopy, in the tropical forests of Central and South America. Let's find out why they go so slowly.

Sloths are slow because their leaf diet gives them little energy and their bodies use energy very slowly. Sloths mostly eat leaves. Leaves give sloths very little energy, so sloths get few calories from their food.

A sloth's stomach has four chambers full of bacteria that help break down the tough leaves. A single leaf can take about a month to travel through a sloth's body.

Moving slowly helps sloths go unnoticed by hunters that find prey by sight. Sloths are hunted by big birds and big cats, such as harpy eagles, jaguars and ocelots. A curled-up sloth can look like a termite nest or a knot in the wood.

A sloth's fur is home to more than the sloth. Green algae grow in it. Sloth hairs have grooves or cracks where algae can take hold and grow. The algae help the sloth blend in with the green leaves. Moths, beetles and other tiny animals live in the fur too.

About once a week, a sloth climbs down from its tree to go to the bathroom. When it does, it can pass up to about one-third of its body weight. Three-toed sloths can turn their heads about 270 degrees, almost all the way around. Sloths are also good swimmers.

There are two kinds of sloth: two-toed sloths and three-toed sloths, named for the claws on their front feet. You may have heard that sloths are a kind of monkey. In fact, sloths are related to anteaters and armadillos, not to monkeys. A two-toed sloth is about the size and shape of a small dog.

Words to know

• algae: green growth
• chambers: stomach parts
• bacteria: tiny living things
• grooves: cracks

The short version

Sloths move slowly because their leaf diet gives them little energy and their bodies use energy very slowly. A sloth's stomach has four chambers full of bacteria that help break down tough leaves, and one leaf can take about a month to pass through. Moving slowly also helps sloths go unnoticed by hunters that find prey by sight.

Quick facts

• Sloths live in trees, high up in the rainforest canopy, in the tropical forests of Central and South America.
• There are two kinds of sloth: two-toed sloths and three-toed sloths, named for the claws on their front feet.
• About once a week, a sloth climbs down from its tree to go to the bathroom.
• Sloths are related to anteaters and armadillos, not to monkeys.
• Three-toed sloths can turn their heads about 270 degrees, almost all the way around.