Pale-throated three-toed sloth (Bradypus tridactylus)

Also known as: Pale-throated sloth
KingdomAnimalia
PhylumChordata
ClassMammalia
OrderPilosa
FamilyBradypodidae
GenusBradypus (1)
SizeHead-body length: 50 - 60 cm (2)
Tail length: 5 - 6 cm (2)
Average Bradypus weight: 4 - 4.5kg (2)
Top facts

The pale-throated three-toed sloth is classified as Least Concern (LC) on the IUCN Red List (1).

The name of the genus to which the pale-throated three-toed sloth (Bradypus tridactylus) belongs, Bradypus, comes from Ancient Greek words meaning ‘slow feet’, referring to the leisurely and unhurried lifestyle of these animals (2).

The pale-throated three-toed sloth is mostly dark brown, with black patches on its hands, shoulders, back and thighs (1). Some individuals may also have irregularly shaped off-white patches on their back (2). All Bradypus species can appear slightly greenish due to the symbiotic algae that grow within their pelage which help to camouflage the individual in its arboreal habitat (3). As the pelage is made up of dense, coarse hair, it provides a certain level of protection against predators and adverse weather conditions (2).

The male pale-throated three-toed sloth can be identified by the broad black line and rounded orange-yellow marking on its back, which are absent in the female (1) (2). This species can be differentiated from other Bradypus sloths due to its white or yellow-buff throat (4), as well as the lack of dark markings on its face and its pale forehead (2) (4). The head of the pale-throated three-toed sloth is rounded (2) and, similarly to other Bradypus species, it has extra vertebrae within its neck, which make it extremely flexible (3).

The female pale-throated three-toed sloth is slightly larger than the male (5) and lacks the orange patches on its back, although some females may have dull orange areas around their ears (2). Both sexes have a short, stubby tail (2).

The arms of the pale-throated three-toed sloth are slender and are longer than the legs, usually by around a third. Each hand and foot has three strong, sharp, almost semi-circular claws that are around 7.5 centimetres long. The digits of all sloth species are bound together by flesh, making them relatively immovable (2).

The pale-throated three-toed sloth is found in Venezuela, Brazil, Guyana, Suriname, Bolivia and French Guiana (1) (4). This species is not known to occur south of the Amazon River (1).

The arboreal pale-throated three-toed sloth is found in lowland and montane tropical forests (1). Although this species spends most of its life in the trees, it is also a competent swimmer and is able to cross rivers in order to travel to other areas (2).

The biology of the pale-throated three-toed sloth is relatively unknown, although reproduction is thought to occur throughout the year, with a single young produced annually (2) (4). In northern Guyana, most births occur at the beginning of the dry season, which runs from late July to September (2) (4). The gestation period of this sloth is unconfirmed (6), although it is thought to be between four and six months (2) (4). Similarly to other Bradypus species, it is likely that the young of this species are nursed for around one month after birth and will remain with the female for up to a year to learn how to forage (6). The male and female pale-throated three-toed sloth are both known to reach sexual maturity at between three and six years old (1).

Although the pale-throated three-toed sloth is mostly active in the day, it is occasionally active at night (2) and is usually solitary, with the exception of females and their young (2) (4). The diet of this species is thought to consist mostly of the leaves from Cecropia trees (4), although the leaves of other trees may also be taken (4). Due to its low-energy diet, the pale-throated three-toed conserves its energy by sleeping for around 20 hours per day (2).

There are not currently known to be any threats to the pale-throated three-toed sloth (1) and it has a wide distribution in one of the most pristine and untouched areas of the Amazon Basin (2). Although this species is not considered to be threatened, the population declines of other Bradypus species have been attributed to habitat destruction and hunting (2).

There are not known to be any conservation measures currently in place for the pale-throated three-toed sloth, although there are known to be many populations living within protected areas (1). As the biology of sloths is poorly known, especially their reproduction, additional research would be highly beneficial for creating appropriate conservation measures for the future (6).

Find out more about the pale-throated three-toed sloth:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
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  1. IUCN Red List (May, 2014)
    http://www.iucnredlist.org/
  2. Natural History Museum - Bradypus tridactylus (May, 2014)
    http://www.nhm.ac.uk/nature-online/species-of-the-day/evolution/bradypus-tridactylus/
  3. Nowak, R.M. (1991) Walker’s Mammals of the World. The Johns Hopkins University Press, Baltimore and London.
  4. Gardner, A.L (Ed.) (2007) Mammals of South America, Volume 1: Marsupials, Xenarthrans, Shrews, and Bats. University of Chicago Press, Chicago, Illinois.
  5. Hayssen, V., van Tienhoven, A. and van Tienhoven, A. (1946) Patterns of Mammalian Reproduction: a Compendium of Species-Specific Data. Cornstock Publishing Company, Ithaca, New York.
  6. Peres, M.A., Benetti, E.J., Milazzotto, M.P., Vistin, J.A., Miglino, M.A. and Assumpção, M.E.O.A. (2008) Collection and evaluation of semen from the three-toed sloth (Bradypus triactylus). Tissue and Cell, 40: 325-331.