The Brown Throated Sloth (Bradypus variegatus)

brown throated sloth in a tree
Photo Credit

Appearance

Coat

With its adorable super-hero style mask over its eyes, the Brown Throated Sloth is probably the one that most people think of when you tell them how much you LOVE sloths.

They have greyish brown to beige fur on their body, with darker brown fur on their throat, forehead and the sides of their face.

Their face is paler, with the well recognised dark strip running accross their eyes.

They have very cool haircuts. Their hair tends to form a fringe across their foreheads.

Males have an interesteing patch of short orange fur with a black strip and spots on their upper back. This is called a speculum. Females have long back hair with spots and stripes, but no orange colorings for the poor ladies.

The markings on their back are unique to each sloth, a bit like our fingerprints. This makes it much easier for researchers to identify individual sloths.

Their fur hangs backwards, to allow the water to run off them as they hang upside down from the trees.

Their fur is generally inhabited by a species of moth called Cryptoses choloepi (known as a sloth moth). This moth produces a fertile environment in the sloth’s coat which allows algae to grow. This can give the sloth a green tinge and a handy camouflage, but it also provides the sloth with a nutritious plant food growing right there on their back!

Arms and legs

As you can see in the picture, the Brown Throated Sloth is a three toed (or fingered) sloth. Both its forearms and hindlegs have three claws.

Their claws can grow to be 7-8 cm long on their hands, and 5 – 5.5 cm long on their feet.

Brown Throated Sloths have arms that are twice as long as their legs.

Size

Both male and female brown throated sloths grow to about 42 – 80 cm in height. Adults weigh 2.25 – 6.3 kg (again – no difference between the boys and the girls).

Their heads are small in relation to their body and their mouth is an ever-appealing smile shape.

Skeletal features

They have a stumpy tail, about 4 inches (10cm) long.

Most mammals have 7 vertebrae, but three toed sloths have 9. This allows them a much greater rotation – they can turn their neck about 270 degrees. This comes in very handy when they’re going for a swim as it allows them to keep their head out of water much more easily. It also allows them to scan for predators, like harpy eagles and jaguars, without using too much energy in moving their body position.

Brown Throated Sloths have 12 sets of ribs (24 in total).

Organs

Brown throated sloths have no gall bladder, appendix or cecum.

Habitat

Brown Throated sloths live in the neotropical ecozone of Central and South America. They can be found in Honduras, Nicaragua, Panama, Venezuela, Costa Rica, Bolivia, Ecuador, Brazil and eastern parts of Peru.

They can be found in a variety of environments. Dry forests and evergreen ones.

1200m (3,900ft) is about as high above sea level as they’ll get, but some adventurous individuals have been found up even higher.

Diet

Bradypus sloths are strict vegetarians and are pretty selective about which leaves they eat. Overall, they can eat up to 96 different types of leaves, but each individual sloth usually chooses from just 5 or 6 different tree species.

They are thought to change trees every couple of days.

Ten upper and eight lower molars, which are simple and peg like, help them slowly chew their leaves each day. They don’t have any incisors.

Behavior

Brown throated sloths sleep between 15 to 18 hours each day. They are active for only brief periods of time.

They are solitary creatures who inhabit the high canopy of the forest and only come down to the ground about once a week to visit the lavatory. They don’t travel very far in their lifetimes – their range is about 0.5 to 9 ha (1.2 to 22.2 acres). Within a typical range, a sloth might visit 40 trees but it tends to specialise in one type – perhaps even spending one fifth of its time in that type of tree.

They are capable swimmers who are active in both the day time and the night time.

Mating and Breeding

Brown throated sloths have no external genitalia.

The female lets out a loud shrill scream during mating season to attract the boys. It apparently sounds like a woman screaming – an ‘AY AY’ sound.

The life expectancy of a Brown Throated Sloth is about 30 years, and both males and females reach sexual maturity at 3 years of age.

No one knows exactly – but they think that the gestation period is about six months.

A single baby is born, and hangs on to mom for the next 8 to 12 months. Baby learns how to select the right type of tree and mom passes on her preferences for specific trees to her offspring.

Babies are weaned at about 4-5 weeks, then they start learning about leaves by licking their mom’s mouth.

After about a year, mom moves far away from her baby, but stays within her territory.

Threats and Conservation

Brown Throated Sloths are classified as least concern, but some populations are threatened by the destruction of their habitat. In the Atlantic Forest of Brazil, for example, the Brown Throated Sloths have a very low genetic diversity and are at risk from hunting. In Colombia there is a growing illegal pet trade. These amazing fringed friends are also at risk from being killed on the roads.


Recommended Reading

Brown Throated Sloth – Wikipedia

World Land Trust

Sloth Sanctuary Costa Rica

Sloth Species: What are the different types of sloths?

Are there different species of sloths?

How many types are there?

What do people mean when they talk about species of sloths – do they mean the two and three fingered types?

Let’s have a closer look at the relationship between the different sloth species to get a better understanding of our two and three fingered friends.

Biological classification chartSloths and Evolution

You might be quite surprised to learn that two toed sloths are actually not all that closely related to three toed sloths. In fact, they’re about as closely related as you and I are to baboons.

The last time two toed and three toed sloths shared a common ground dwelling ancestor was about 30 million years ago (about the same time that us human types split from our baboon relations (although perhaps it doesn’t feel like it at some Christmas get togethers?)

It is thought that three toed sloths were the first to climb up into the trees to get a good view. The two toed sloth made its tree-change millions of years later!

What this means is that they’ve been evolving separately, although quite similarly, for all that time. This is called convergent evolution and is of quite a lot of interest to some scientists. The different number of fingers, and some differences in the way their muscles connect to their bones, is the giveaway that they are actually quite distant relatives who have each found their own special ways to live in the trees.

What’s pretty weird though, is that they both climb down from the trees, putting their lives at risk, to poop (and do the subsequent poop dance) once a week. This peculiar habit has evolved not just once, but twice. Holy sloth dung, that’s pretty amazing!

Order

So, two-toed sloths are quite distant relatives of three-toed sloths. If you have a look at the chart above, they both belong in the same order (four categories from the bottom).

The order is called Pilosa and it is one the smallest orders in the mammal class. It consists of just two suborders:

  • Folivora – sloths
  • Vermilingua – anteaters and armadillos

Fun fact – Folivora means ‘leaf eater’ and Pilosa means ‘hairy’.

Family and Genus

Moving down the rung of the biological classification chart we come to Family. Here’s where sloths get split up into five different groups. What’s terrible, though, is that three of the families are extinct. So that leaves us with two:

  • Bradypodidae – Three toed sloths are the only members of this family (and genus Bradypus)
  • Megalonychidae – This family gets split into two genus:
    • Megalonyx – an extinct genus of ground sloths.
    • Choloepus – Two toed sloths

Species

Finally we get to answer your question about how many species of sloth there are!

The two different existing sloth genus, Bradypus and Choloepus, are each split into different species.

Bradypus (Three Toed Sloth)

There are four species of three toed sloths:

  • Brown Throated Sloth (Bradypus variegatus)
  • Pale Throated Sloth (Bradypus tridactylus)
  • Maned Sloth (Bradypus torquatus)
  • Pygmy Three Toed Sloth (Bradypus pygmaeus)

Choloepus (Two Toed Sloth)

There are two species of two toed sloths:

  • Linnaeus’s Two Toed Sloth (Choloepus didactylus)
  • Hoffmann’s Two Toed Sloth (Choloepus hoffmanni)

So there you have it! If you’d like to read more about each species of sloth, then follow the links on each species name.

 

Sloth cuddling with its mom
Photo by Eric Kilby 

Differences between Two Toed and Three Toed Sloths

Clearly – a major difference is that two toed sloths have two toes, and three toed sloths have three. But it’s important to note that we are only actually talking about their ‘fingers’ here. Both types of sloth have three claws on their hind legs. This is the reason that you’ll notice people starting to refer to them as Three Fingered and Two Fingered Sloths.

Another significant difference is that two toed sloths have 5 or 6 vertebrae in their necks. Most mammals have 7. Three toed sloths have 9! This makes them able to turn their head 270 degrees, which comes in very handy when they go for a swim as they are able to keep their head out of the water easily.

Three toed sloths have small tails, but their two fingered friends have no tail at all.

Two toed sloths are larger. They’re generally 58-70 cm long and weigh 4-8 kgs. Three toed sloths are only about 45 cm long and weigh 3.5-4.5 kg.

Two toed sloths are mostly nocturnal. Three toeds are diurnal (which means they’re active in the daytime).

References

National Geographic

Two toed sloth -Wikipedia

Three toed sloth – Wikipedia

Sloths in the wild: Where do sloths live?

You’re planning your next world wide trip and want to make sure you stop in at the right places so that you can visit all the
sloths. Or maybe your friend said to you today, hey friend – where can sloths be found? and you were embarrassed to admit that you didn’t know the answer. Well, we’re glad you are here because we are on a mission to answer the very important where do sloths live question for you.

As you know (or if you don’t, it’s ok – don’t panic, you can read all about it here), there are different types of sloths in the world. So lets talk about where each type of sloth lives in the wild.

Pygmy Three-Toed Sloth

If you want to visit the Pygmy Three-Toed Sloth (Bradypus pygmaeus) (also known as the monk sloth or dwarf sloth) then you’ll need to book yourself a ticket to Isla Escudo de Veraguas. This is a Carribean island of the Republic of Panama which is only 4.3 square kms (1.7 sq mi). Once you’re there, find your way to the red mangroves. Hopefully then, with quite a lot of luck, you’ll find one of the remaining Pygmy Three-Toed Sloths in the world. In 2012 it was estimated that only 79 existed. This means, of course, that they are critically endangered.

Map of the areas that pygmy three toed sloths live
Photo credit

Brown-Throated Sloth

The Brown-Throated Sloth  (Bradypus variegatus) is a three-toed friend who prefers to hang out in the neotropical ecozone of Central and South America.

The most common and widespread of the three-toed sloths, it can be found in Honduras, Nicaragua, Costa Rica, Panama, Venezuela, Colombia, Ecuador, Bolivia, Brazil and eastern Peru. People have thought they’ve seen Brown-Throated Sloths north of the Amazon Rainforest and east of the Rio Negro – but most likely those poor sods had them confused with the Pale-Throated Sloths (they do look very similar, we can’t blame them too much).

Covering such a large area, it’s not too suprising that the Brown-Throated Sloth can be found in lots of different environments. Dry forests, evergreen ones – even natural areas that have been messed with by humans. 1200m (3,900ft) is about as high above sea level as they’ll get, but some adventurous individuals have been found up even higher.

Map of where Brown Throated Three Toed Sloths live
Photo credit

Maned Three-Toed Sloth

In the 1950s,The Maned Three-Toed Sloth (Bradypus torquatus) could be found in the Bahia coastal forests of Bahia, Rio de Janeiro and Espirito Santo. Now, thanks to deforestation and hunting, they can only be found in the Atlantic coastal rainforest of southeastern Brazil.

Maned Three-Toed Sloths like it wet. They live in areas with no dry seasons, and annual rainfall of at least 120cm. However, as they don’t mind munching on quite a range of leaves, they can also be found in semi-deciduous and secondary forest.

Area map of Maned Sloth
Photo credit

Pale-Throated Sloth

The Pale-Throated Sloth (Bradypus tridactylus) lives in tropical rainforests in northern South America. More specifically, have a look for them in Suriname, French Guiana, Brazil (north of the Amazon River), Guyana and western parts of Colombia and Venezuela.

Pale Throated Sloth Area Map
Photo credit

Linnaeus Two-Toed Sloth

The Linnaeus or Linne’s Two-Toed Sloth (Choloepus didactylus) live in the tropical rainforests of Colombia, Guyanas, Peru, Ecuador, Venezuela and Brazil (north of the Amazon River). It is possible that they also live in parts of Bolivia. If you see some on your travels there, please be sure to let us know.

Map showing where Linne's Two Toed Sloth live
Photo credit

Hoffmann’s Two-Toed Sloth

The Hoffmann’s Two-Toed Sloth (Choloepus hoffmanni) live in tropical rainforests ranging from sea level up to about 10,800 ft, or 3.3km, above sea level. They are actually separated into two different areas of Central and South America, divided by the Andes. One group can be found ranging from western Ecuador up to eastern Honduras. The other group inhabits the areas of western Brazil, eastern Peru and northern Bolivia. I wonder if they have different accents.

Hoffmans Two Toed Sloth Area Map
Photo credit