Brown-Throated Three-Toed Sloth

Brown-Throated Three-Toed Sloth

Brown-throated sloth

Bradypus variegatus
Population size
Life Span
30-40 yrs
0.24 km/h
2.3-6.3 kg
42-80 cm

The slowest mammal in the world, the Brown-throated three-toed sloth is an unusual animal. The word 'sloth' means slow. And indeed, this sluggish animal is so sedentary that algae appear on its fur. Brown-throated three-toed sloths are endemic to rainforest canopies of Central and South America. Due to hanging onto branches with their long claws, they are able to consume leaves, located too high for other animals to reach. On the other hand, these long claws create difficulties as they walk on the ground. Hence, the Brown-throated three-toed sloths are mostly arboreal, living in trees.


These sloths occur in tropical and semi-deciduous forests as well as subtropical lowlands and swamps of South America and southern Central America (Bolivia, Brazil, Colombia, Costa Rica, Ecuador, Honduras, Nicaragua, Panama, Peru, Venezuela).

Brown-Throated Three-Toed Sloth habitat map

Climate zones

Habits and Lifestyle

Brown-throated sloths usually have very short periods of activity between long sleeps. As a general rule, they sleep about 15 - 18 hours per day and can be active during both day and night. Adult brown-throated sloths display solitary behavior and socialize extremely rarely: two adult sloths have never been seen together in the same tree. Fighting does not appear to occur between individuals, but they are known to protect their territories, food and other property. During most of the day, sloths can be seen sitting in the forks of tree branches or hanging from branches in the middle layer and top of trees. They thermoregulate their bodies due to living in trees with exposure to the sun: when it gets cold, these animals exposure to the sun; during hot weather, they descent to find shelter in branches. Brown-throated sloths cannot walk and stand, hence they move onto the ground by propelling themselves with their forelegs.

Diet and Nutrition

These animals are herbivores (folivores and frugivores), they mainly feed upon leaves, flowers, fruits and other parts of tree.

Mating Habits

in South America: July-November, in Central America: February-May
5-8 months
1 baby
5-10 months
baby, pup

In the past, these animals were believed to be monogamous, although it’s not exactly true: they are solitary and males leave soon after mating without taking part in raising of offspring, suggesting that Brown-throated sloths are either polygynous or polygynandrous (promiscuous). Females give out calls in order to attract males. As a response to the call, male sloths engage in fight and the winner mates with the female. Populations in South America mate from July to November, while these in Central America mate in February-May. The females do not construct any nests. Gestation period lasts for 5 - 8 months, yielding a single baby. The young sloth is completely weaned at 4 - 5 weeks old, but remains attached to its mother for the first 5 - 10 months of its life. Sexual maturity is reached at 3 - 5 years old in males, and at 3 years old in females.


Population threats

Although there are no obvious threats to this species on the whole, some subpopulations in Colombia and the Atlantic Forest (Brazil) greatly suffer from deforestation, which causes degradation and fragmentation of their natural habitat. In some parts of their range, the Brown-throated sloths are hunted by local indigenous people. In Columbia, some individuals (primarily - infants) are threatened by illegal pet trade, being caught and sold as pets to tourists. This leads to population decline and poses a serious danger to this species in the wild.

Population number

According to IUCN, the Brown-throated sloth is widespread throughout its range but no overall population estimate is available. These animals are classified as Least Concern (LC) on the IUCN Red List.

Fun Facts for Kids

  • The long and coarse fur of this animal is normally light brown, though may seem to be green because of blue-green algae, growing there.
  • At a few weeks old, infant sloths get algae colonies into their fur from their mothers. Algae, growing on their fur, do not occur anywhere else. These animals allow algae to live in their fur, providing it with required moisture. Algae, in turn, serve as camouflage, helping them escape predators.
  • Males of this species are identified by a bright yellow or orange colored marking between their shoulders. In this patch, they possess scent marking glands, which are used to attract receptive females.
  • These sloths practice two types of resting: "awake-alert" - this is when they rest with open eyes and blink; and "behavioral sleep" – this is when they are suspended from a tree with their eyes closed.
  • These accomplished swimmers drop themselves off branches into rivers to swim. They are known to use breaststroke style, just like humans.
  • Muscles make up only 25% of a sloth's body. So when it's cold, the animal cannot shiver in order to warm up.
  • Due to a specific shape of its mouth, the Brown-throated sloth seems to smile constantly. The flexible head of this animal can rotate up to 90 degrees.


1. Brown-Throated Three-Toed Sloth Wikipedia article -
2. Brown-Throated Three-Toed Sloth on The IUCN Red List site -

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