38 Fun Facts About Sloths

What do two-toed and three-toed sloths have the same number of?

Hind toes: every sloth has three on each back foot, and the names count only the front limbs, where two-toed sloths have two digits, which is why some people call them two-fingered sloths.

In what geographical region are sloths primarily found?

Central and South American rainforests are the only home of living sloths: their metabolism is so slow that they cannot keep warm outside the tropics.

Sloths are slow in the trees, but what are they surprisingly good at?

Swimming: a sloth will sometimes drop from its branch straight into a river and pull itself across with its long arms.

Sloths eat, sleep and usually even do what while hanging from a branch?

Give birth: a sloth mother usually delivers her single baby while hanging from a branch, and the newborn has to cling to her fur from its first moment.

What does a sloth's very low metabolic rate lead to?

Food digestion takes an exceptionally long time: no other mammal digests more slowly, and a sloth's stomach is kept constantly full of fermenting leaves.

Why do sloths move so slowly?

To conserve energy from their low-calorie diet: leaves supply so little fuel that sloths burn energy at roughly half the rate expected for a mammal of their size.

What grows in a sloth's shaggy coat and tints it in the wet season?

Green algae, not the hair itself, supply the colour: a sloth's long outer coat is really pale brown to grey, and the green is a living growth on it.

Three-toed sloths climb all the way down to the ground, dig a hole and relieve themselves roughly how often?

About once a week, three-toed sloths climb down, dig a small hole at the foot of a tree and cover it afterwards; why they take the risk instead of going from the canopy is still debated.

How do baby sloths learn which leaves to eat?

By licking their mother's lips: a baby samples the leaves she is chewing and so inherits her taste for particular trees.

Two-toed and three-toed sloths evolved their upside-down tree life separately, making them a textbook case of what?

Convergent evolution: protein and DNA studies place two-toed sloths beside the extinct Mylodon and three-toed sloths with the giant megatherioid ground sloths, so each line took to the trees on its own.

Besides sloths, which mammal breaks the rule of seven neck vertebrae?

Manatees make do with six; even the giraffe, with its two-metre neck, has the standard seven.

What do a sloth's enamel-free, peg-like teeth do all its life?

Keep growing: with no enamel cap, each peg of dentine is worn down as the sloth chews its leaves, so it never stops growing to make up the loss.

The sloth's Spanish name, perezoso, is also the everyday Spanish word for what?

Lazy: perezoso, like the French paresseux and the German Faultier, simply calls the animal a lazybones, and the English word sloth itself first meant laziness.

Which ability do three-toed sloths owe to the extra bones in their necks?

Turning their heads 270 degrees: three-toed sloths have eight or nine neck vertebrae where almost every other mammal has seven, so they can look well behind them on either side.

Sloths' reputation for sleeping 15 or more hours a day came from studying which animals?

Captive sloths: laboratory animals slept nearly 16 hours a day, but brain-wave recorders fitted to wild three-toed sloths in 2008 showed they sleep less than 10.

What is a major risk for sloths when they descend to the forest floor?

Predation: almost helpless out of the trees, a sloth on the ground is within easy reach of jaguars and ocelots, which is why it comes down so rarely.

How do sloths often make up for their poor control of body temperature?

By sunning themselves: like cold-blooded animals, sloths climb into the sun to warm up, because their body temperature drifts with the air around them.

Which of these sloths was listed as 'critically endangered' on the IUCN Red List in 2025?

Pygmy three-toed sloths live only on Isla Escudo de Veraguas, a small island off Panama, where habitat loss and hunting put the whole species at risk.

Which two senses do sloths mainly rely on to find food?

Smell and touch: with weak eyesight and hearing, a sloth finds food by scent and feel, then pulls it to its mouth with its claws.

A sloth's fur grows from belly to back, the reverse of most mammals, to help with what?

Shedding rain while upside down: because a sloth spends its life hanging belly-up, its hair parts along the stomach and points toward the back, so water runs straight off.

Why do sloths often frustrate hunters even after being shot from below?

They stay hooked in place on the branch: a sloth's curved claws lock around the limb and keep the body hanging even after death, so a shot animal often never drops to the hunter below.

Unlike their leaf-eating three-toed cousins, two-toed sloths occasionally eat which of these?

Insects: two-toed sloths live mostly on leaves and fruit but will snack on the odd grub, which is why they are classed as omnivores while three-toed sloths keep almost wholly to leaves.

Compared with most mammals of their size, sloths have far less of which tissue?

Muscle makes up only about a quarter to 30 percent of a sloth's weight, against 40 percent or more in most mammals, which is why a cold sloth cannot shiver to warm up.

How big could extinct ground sloths such as Megatherium grow?

As big as an elephant: Megatherium weighed up to about four tonnes, and it could rear up on its hind legs to reach leaves far above the ground.

The name of the mammal order Pilosa, to which sloths belong, comes from the Latin for what?

Hairy: Pilosa comes from the Latin pilosus, from pilus, 'hair', the same root that gives English 'depilate', a fair label for animals with coats this shaggy.

Sloths are most closely related to which animals, sharing the order Pilosa with them?

Anteaters are the sloths' closest relatives despite their very different lives: toothless insect-eaters and slow tree-climbers together make up the order Pilosa, with armadillos as their next of kin.

Far from the Amazon, the maned sloth survives only in which shrinking Brazilian forest?

Atlantic Forest: the maned sloth lives only in fragments of this coastal rainforest, and the clearing of its trees is the main threat to the animal's survival.

Which US president named the giant ground sloth Megalonyx from its fossil claws?

Jefferson described the animal's huge claw bones to the American Philosophical Society in 1797 and named it Megalonyx, 'great claw'; the species Megalonyx jeffersonii was later named in his honour.

How do sloths get across open ground between trees?

They drag themselves by their claws: sloth limbs are built for hanging, not for bearing weight, so on the ground the animal must grip something and haul its body forward.

Which of these large birds is a primary aerial predator of sloths?

The Harpy Eagle, one of the world's largest and most powerful eagles, is a primary aerial predator of sloths, snatching them from the trees with powerful talons.

When are two-toed sloths active?

Only at night. Two-toed sloths are nocturnal, feeding and moving after dark, whereas three-toed sloths may be active by day or night; both kinds spend most of their time motionless.

What type of stomach do sloths possess, adapted for digesting tough plant matter?

Multi-chambered: a sloth's large stomach has several compartments in which symbiotic bacteria slowly ferment tough leaves the animal could not otherwise digest.

What is a sloth's main defence against predators while it hangs in the canopy?

Camouflage and slow movement keep sloths from catching the eye of the cats and hawks that hunt them by sight.

How does a female three-toed sloth attract a mate?

She screams: a female in season gives loud, shrill cries, and males are drawn towards the sound as it echoes through the trees.

What state does a sloth enter when its body temperature drops to about 20 °C?

Torpor sets in at about 20 °C; a sloth's temperature normally ranges between 25 and 35 °C, and that sensitivity to cold confines the animals to the tropics.

What feature of sloth hair gives the tiny organisms that tint it a place to grow?

It is grooved: the organisms that tint the coat lodge in grooves or cracks along each outer hair, and the fur also shelters moths and beetles, some found nowhere else.

Why do sloth moths lay their eggs in sloth dung?

Their larvae feed on it: the moths leave the fur when the sloth climbs down to relieve itself, lay their eggs in the fresh dung, and the next generation flies up into the canopy to find a sloth.

Which genus name, Greek for 'slow-footed', belongs to the three-toed sloths?

Bradypus joins the Greek words for 'slow' and 'foot', with the same brady- as bradycardia, a slow heartbeat; two-toed sloths are Choloepus, 'lame-footed'.