The maned three-toed sloth spends practically its entire life in trees. It feeds strictly on leaves, twigs and buds and is well adapted to this way of life (5). It does not have incisors and crops leaves with its hard lips instead. The side teeth grow continuously as they are worn down by the grinding of food. Common to all sloths, the stomach is long and multi-chambered, and is filled with cellulose-digesting bacteria, which enables the extraction of energy from nutrition-poor leaves (6). It also has a low metabolic rate at 40-45% that of a typical animal their size, and it takes days to process food that other ruminants could process in hours. This benefits the sloth though, by enabling it to survive on relatively little food (3) (6). As the sloth has such a low metabolic rate, it is an extremely slow and sluggish mover in the trees, travelling an average of 38 meters a day, and sleeping for around 15 hours of the day. It also maintains a low body temperature, from 30-34ºC, which helps conserve energy (3). This unusual animal has around half the body muscle of most other mammals, presumably to make more space for the digestive chamber, and so it cannot keep warm by shivering (3). Instead they select trees with exposed crowns and regulate their body temperature by moving in and out of the shade (4). Another unusual feature of this mammal is that it spends most of its time hanging upside down from branches and as a result, many of its internal organs are in different positions from other mammals (5). Sloths are also surprisingly good swimmers (4). The maned three-toed sloth leads a solitary life and has a home range as large as 16 acres which can overlap with those of other individuals (3). It travels from tree to tree using canopy creepers, or more rarely by descending to the forest floor and crawling to the next tree (2). In the trees its motionless state and camouflage makes it difficult to see, but descending to the exposed forest floor renders the sloth vulnerable to predators such as jaguars and eagles, especially as it cannot escape by moving quickly and can only use its claws in defence (5). Due to these threats it only leaves its tree to find more food, to defecate around once a week and to find a mate (6). Females give birth once a year to a single offspring after a gestation period of about six months. The young clings to the mother's belly and is carried for up to six months, until it is strong enough to hang from branches unaided (4). There is a strong bond between the female and her young which is important for learning and development and the young inherit a portion of the mother's home range. Even when the young leaves the mother's home range, it maintains contact through calls (7).

The maned three-toed sloth is the rarest of the five sloth species and is only found in Brazil (3). The name refers to its black mane of hairs, each up to 15 centimetres long, running down the back of its neck and over the shoulders (2). Like other sloths it has long limbs, a short body and a stumpy tail (2). The head is round, with a flat face and small ears hidden in the fur. Its fur is coarse, long and shaggy, and grows in the opposite direction to most mammals; from the stomach to the back. The cream and tan coloured coat is usually tinged green from the blue-green algae that live in grooves in the hair, providing great camouflage for the sloth in the trees (3). The reference in the name to three-toes is misleading; all species of sloth actually have three toes on the hind limbs, but they are grouped into two genera which can be distinguished by the number of fingers on the forearm. The two-fingered forms are known as two-toed sloths, and the three-fingered forms are called the three-toed sloths (3). These digits end in curved claws, measuring up to 4 inches long and are ideally shaped to hook around tree branches. Three-toed sloths also have an elongated neck due to an additional vertebra. This allows more flexible movement of the head and enables them to gaze at their surroundings in a 270 degree arc (3).

Bradypus torquatus is restricted to the Atlantic coastal forests of eastern Brazil. Historically, it possibly occurred throughout the coastal forest of Bahia through to the state of Pernambuco (footnote by O. Pinto in Wied's 19th century account, Coimbra-Filho 1972). At present, the southern part of the state of Bahia is the primary stronghold for the species. A recent record of the species is in the state of Sergipe (Chagas et al. 2009) but thus far no records have been collected in the adjacent state of Alagoas. The extensive deforestation of suitable habitat in this state suggests that it is unlikely to survive there. A natural biogeographic gap occurs in northern Espírito Santo, perhaps due to a higher degree of deciduity in the forests of this region (Hirsh and Chiarello in press). The species does not occur from the left bank of Doce River to the vicinity of Mucuri River. It has been reported from extreme northern Minais Gerais on the left bank of Jequitinhonha River. Bradypus torquatus has been introduced to some National Parks in Espírito Santo (Caparaó National Park) and Rio de Janeiro (Tijuca National Park), among other areas, although it is not known if the species is still present at these sites. It ranges from sea level to 1,290 m asl.

Bradypus torquatus occurs in patches of the coastal Brazilian Atlantic rain forest within the states of Bahia, Espirito Santo, and Rio de Janeiro.

Biogeographic Regions: neotropical (Native )

Historic Range:
Brazil

This species is restricted to the remaining fragments of coastal rainforest in Brazil, in the states of Bahia, Espirito Santo, and Rio de Janeiro (1).

Species in the genus Bradypus all have fur with a greenish tint, which is due to the growth of algae on the hairs. The fur grows from the hind legs towards the head. This unique growth pattern helps to accommodate their upside-down lifestyle, shedding water from the fur, as sloths are strict arboreal mammals who spend the vast majority of their time in a suspensory position. From the nape of the neck to the shoulder region, maned three-toed sloths have fur that is approximately 15 centimeters in length and projects as shaggy plumes, giving them a maned appearance. Bradypus torquatus males possess an emblematic black mane around the dorsal region of the neck, this black mane is absent in females and infants. The black mane might be a visual signal that helps females recognize males.

Maned three-toed sloths are brown on the face and chin and the head can rotate beyond 90 degrees. They have long limbs that range in size from 100 to 115 millimeters in length. From the tip of the nose to the inflection point of the tail, individuals measure 450 to 500 millimeters. They have short, stubby tails that ranges in size from 48 to 50 millimeters. Maned three-toed sloths are the largest of three-toed sloth species, from 3.6 to 4.2 kg. Females tend to be larger and heavier than males. However, it is difficult to distinguish sexes externally, the only reliable method is karyotype analysis. Geographical variation exists among both sexes; maned female sloths that live in low altitude regions (0 to 350 meters) are smaller than females that live in colder and higher altitudes (600 to 1000 meters). This is similar to Bradypus variegatus in Bolivia, where larger body sizes are common in high altitude forests, whereas smaller body sizes are found in warmer lowlands of the Amazon. Female sloths of the species Bradypus tridactylus are also heavier and larger than males. Maned three-toed sloths have feet without any free toes. They have 3 long, curved claws that form a hook, allowing them to suspend from branches. The claws also allows them to grasp objects against the palm of the hand with a pincer-like grip. The dentition of B. torquatus consists of five peglike teeth on each side of the maxilla and four teeth in the mandible. Maned three-toed sloths have no true canines or incisors, but rather, a set of cheek teeth that are not clearly separated into premolars and molars resulting in a dentition of 0-0-5 and 0-0-4-5. This dentition is effective in shearing and mashing of leaves. Three toed sloths are characterized by a low metabolic rate and a low core body temperature. This may be an adaptation for feeding on leaves that contain low nutrients. Aside from this, there is little available information regarding the basal metabolic rate of any species in the genus Bradypus.

Range mass: 3.6 to 4.2 kg.

Range length: 450 to 500 mm.

Other Physical Features: endothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: female larger; sexes colored or patterned differently; male more colorful

Habitat and Ecology

Systems

• Terrestrial

Maned three-toed sloths are found at altitudes as high as 1000 meters. The highest concentration of individuals is found in Espirito Santo, Brazil. Habitats in this state are mostly secondary and are classified as dense ombrophilous. In this region, maned three-toed sloth populations are between 100 and 200 individuals. The topography of Espirito Santo is hilly with average altitudes ranging from 600 to 800 meters. Given a lack of published data regarding the climate of Espirito Santo state, scientists have used nearby Santa Lucia, which is 18 kilometers from Espirito Santo state and boasts similar topography, altitude, and canopy cover. Santa Lucia receives heavy rainfall, with an annual average precipitation of 1868 millimeters, and an annual average temperature of 19.9 degrees Celsius. Santa Lucia has a wet and hot season between October and March with a drier and cooler season between April and September.

Range elevation: 0 to 1000 m.

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: forest ; rainforest

Other Habitat Features: riparian

Inhabits tropical evergreen forests at low elevations, especially those with a continuous canopy (4).

Maned three-toed sloths are most numerous in dense forests that contain secondary-growth trees and an abundance of young leaves. They are strictly arboreal folivores with a highly selective diet: 99% leaves and 1% soft twigs and buds. Maned three-toed sloths prefer leaves from Mandevilla, Micropholis venulosa, and Ficus trees. They eat fewer liana leaves than tree leaves, as they prefer to stay camouflaged in the canopy. Remaining in dense foliage allows them to avoid predation by harpy eagles (Harpia harpyja) as well. Maned three-toed sloths digest leaves by bacterial fermentation in a complex stomach consisting of multiple chambers. A preference for young leaves is related to their easy digestion, as mature leaves contain structural carbohydrates that are difficult to digest. They spend twice as much time feeding during the dry season than the wet season. This is attributed to an increase in the demand for food and energy during the dry season.

Plant Foods: leaves; wood, bark, or stems

Primary Diet: herbivore (Folivore )

Maned three-toed sloths are prey for avian predators, such as harpy eagles (Harpia harpyja) and rainforest cats (Puma yagouaroundi and Leopardus pardalis). They may impact the growth of trees through their folivory.

Maned three-toed sloths spend the majority of their time camouflaged in the forest canopy. Young maned three-toed sloths develop and grow rapidly, an adaptive response to greater predation levels in early life stages. Three-toed sloths are active during sporadic periods of both day and night, which may be an adaptation to avoid predators. Sloths are preyed on by harpy eagles (Harpia harpyja) as well as large cats such as jaguarundis (Puma yagouaroundi) and ocelots (Leopardus pardalis).

Known Predators:

• harpy eagles (Harpia harpyja)
• jaguarundis (Puma yagouaroundi)
• ocelots (Leopardus pardalis)

Anti-predator Adaptations: cryptic

Maned three-toed sloths occasionally produce long, high pitched "eee" calls, as has been documented in other sloths. Sloths do not call regularly and cannot be detected by their vocalizations in a methodical way. Adults and infants will call when under duress, when captured, or when handled. Mating calls of any kind have only been observed once over thousands of hours of observation. Maned three-toed sloths have poor vision, but little is known about other modes of perception or communication in these sloths.

Communication Channels: acoustic

Perception Channels: visual ; acoustic

There is very little information regarding the longevity of wild maned three-toed sloths. They do not survive well in captivity, but wild lifespans are estimated at 20 years or more. An individual Choloepus didactylus (Linnaeus's two-toed sloth) was still alive after 28 years in captivity and a captive Choloepus hoffmanni lived for 32 years. However, Choloepus species consume a wider array of food than Bradypus species.

Typical lifespan

Status: wild: 20 (high) years.

Observations: In the wild, these animals are estimated to live up to 12 years (Bernhard Grzimek 1990). Their longevity in captivity could be much longer, though.

The mating system of sloths indicates that males compete with one another for access to females, suggesting that female sloths choose larger and more powerful males with which to mate. Mane size and darkness of male sloths may reflect health and vitality. Males may mate with multiple females. Maned three-toed sloths have been observed copulating while locked in a tight embrace high in the canopy of the forest.

Mating System: polygynous

Maned three-toed sloths are seasonal breeders, with breeding occurring between September and November, near the end of the dry season and the beginning of the wet season. Reproduction may occur at this time of year so that gestation and lactation can occur when temperatures are more favorable and food items are more abundant.  Maned three-toed sloths give birth during the first 6 months of the year, between the months of February and April, during the final 2 months of the rainy season and initial month of the dry season. Females produce a single young after a gestation period of approximately 6 months. Young B. torquatus weigh approximately 300 grams at birth and cling to the mother for the first 6 to 9 months of life. Within two weeks of birth, infant maned sloths begin to ingest leaves. Lactation bears a high cost to the mother of newborns and the early development of folivory in infants may be an adaptation to lessen the cost of lactation. Although leaves are a portion of their diet, newborns suckle until they reach 4 months of age. Infants will remain with the mother for 8 to 11 months. Maned three-toed sloths achieve adult size (>60 centimeters) within 1 to 3 years of birth. Females can become sexually active after reaching adult size, and when the vaginal opening is apparent. For males, once the penis is well-developed at 1.5 centimeters or larger, they are considered sexually mature.

Breeding interval: Three-toed sloths bradypus torquatas are seasonal breeders, giving birth once yearly.

Breeding season: Maned three-toed sloths breed between September and November, near the end of the dry season and the beginning of the wet season.

Range number of offspring: 1 (high) .

Average number of offspring: 1.

Average gestation period: 6 months.

Average birth mass: 300 g.

Range weaning age: 4 (high) months.

Range time to independence: 8 to 11 months.

Range age at sexual or reproductive maturity (female): 2 to 3 years.

Range age at sexual or reproductive maturity (male): 2 to 3 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous

Average number of offspring: 1.

Maned three-toed sloth young are precocial and begin consuming leaves just two weeks after their birth. Knowledge regarding preferred leaves to eat is passed from mother to young. This is critical as they must be able to efficiently recognize food. Weaning occurs after 4 months but juveniles typically stay with their mother for 8 to 11 months, being carried while the mother eats and travels. After this time juvenile disperse from their mother's home range and are considered sub-adults, not yet sexually mature. There is no evidence of male parental investment.

Parental Investment: precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Protecting: Female); extended period of juvenile learning

The following is a representative barcode sequence, the centroid of all available sequences for this species. 

 
There are 5 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
 

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 5
Species: 5
Species With Barcodes: 1

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

According to the International Conservation Union (IUCN), maned three-toed sloths are listed as endangered due to deforestation. Their occurrence in the highly threatened Brazilian Atlantic forest makes them especially vulnerable to habitat changes and isolation.

US Federal List: endangered

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: endangered

Current Listing Status Summary

Status: Endangered
Date Listed: 06/02/1970
Lead Region: Foreign (Region 10) 
Where Listed:


Population detail:

Population location: entire
Listing status: E

For most current information and documents related to the conservation status and management of Bradypus torquatus , see its USFWS Species Profile

Classified as Endangered (EN) on the IUCN Red List 2007 (1).

Population

Population Trend

Major Threats

The habitat of the maned three-toed sloth in the tropical coastal forests of Brazil is threatened by logging, charcoal production, urbanisation, industrialisation and clearance for plantations and cattle pasture (1). Today, the Atlantic Forest is reduced to less than 5% of its original extent and the area of the Mata Atlantica, where the maned three-toed sloth lives, has the highest human population in Brazil (8) (9). This sloth was previously hunted for its meat, and even though it is now protected by law, its numbers have been dramatically reduced and have not recovered (9). There have also been reports of this species being found in tourist areas where people pay to have their photograph taken with it, indicating that hunting is not totally under control (6).

Conservation Actions

Like so many species, the survival of the maned three-toed sloth is inextricably bound to the future of tropical rainforests. The Atlantic Forest, where this sloth is found, ranks among the top five global biodiversity hotspots, partly due to its high number of endemic species (10). There are several conservation measures being taken, which are hoped to protect the maned three-toed sloth. Currently the WWF is working with the local communities of the Atlantic Forest through environmental education programs to protect the habitat of this sloth and many other endangered species in the area (10). The US Agency for International Development (USAID) is working on reduced-impact forest management and on providing alternatives to slash and burn agroforestry (11). Conservation International (CI) has plans to stimulate income through tourism, where agriculture might otherwise have been introduced; in 1998 a canopy walkway was built near the Una Reserve saving 320 acres of valuable rain forest habitat from logging, which is a hopeful message to other conservation projects (8). The maned three-toed sloth has a unique healing ability and is able to survive severe injuries (5). Scientists are also therefore keen to protect and breed this species so they can study the sloth's quick healing abilities and determine whether there could be benefits for human medicinal purposes (11). Efforts to relocate maned sloths in more secure areas of the rainforest have been successful so far, though breeding in captivity has been poor as sloths do not survive for long outside of their natural environment (11). Research projects are focusing on the close relationship between females and offspring so that breeding and re-introduction programs in the future are better informed and more successful (7) (12). These projects are hoped to allow the unique maned three-toed sloth to recover (8).

There are no adverse effects of maned three-toed sloths on humans.

Maned three-toed sloths are important, endemic members of Brazilian Atlantic forest ecosystems.