Mammals

Sloths spend practically their entire lives in the trees, either hanging beneath branches or sitting in a fork. They descend to the ground about once or twice a week to urinate and defecate, and on occasion to move from one tree to another. The sloth is well camouflaged in the trees, but extremely vulnerable on the ground as it moves by crawling slowly on the soles and forearms. However, sloths are not completely defenceless – when faced with a predator, they are capable of inflicting serious wounds with their long, sharp claws. Since sloths tend to stay in one tree for long periods of time, feeding is restricted to that tree and to other plants supported by the tree. The diet consists almost exclusively of young leaves, tender twigs and buds. These items are pulled to the mouth with slow movements of the forelimbs. Since this species does not have any incisors it crops the leaves with its hard lips instead. Like other sloths, this species has a long, multi-chambered stomach filled with cellulose-digesting bacteria. This allows them to extract energy from nutritient-poor mature leaves. Sloths have an extremely low metabolic rate, about half that of most mammals their size. They sleep for around 15 hours each day and maintain a relatively low body temperature (30-34°C) to conserve energy. Body temperature is regulated by moving in and out of the shade in trees. The species generally moves slowly and methodically, although it can progress rapidly when necessary. Individuals are active both night and day, and are primarily solitary, although their large home ranges (3-6 ha) frequently overlap. Maned sloths appear to reach maturity at about three years of age, which is a relatively short time for animals of their size and low metabolic rate. Breeding appears to take place at the end of the dry season (September–November), with females giving birth to a single young each year after a gestation period of around six months. Infants are weaned at around 2-4 months and are independent by 11 months.

Inhabits lowland tropical evergreen forests, particularly those with a continuous canopy.

Unknown.

Declining.

Classified as Endangered (EN B1ab(i,ii,iii)) on the 2006 IUCN Red List of Threatened Species.

The maned sloth is the most threatened of the South American sloth species, owing to its restricted geographical range and the disturbed and fragmented nature of its forest habitat. The Atlantic coastal rainforest of Brazil is diminishing rapidly as a result of logging, charcoal production, and clearance for plantations and cattle pasture. Today, the Atlantic forest is reduced to less than ten percent of its original area, and the Mata Atlântica region in which the species lives has the highest human population in Brazil. Maned sloths have a highly fragmented distribution, with large gaps between the major populations. This means that many existing populations may be too small to be viable. The species has traditionally been hunted for its meat, and this may continue to threaten its survival in some areas, despite now being protected by law.

Although maned sloths occur in at least eight protected areas, it is unlikely that any of these support viable populations, because of the highly fragmented distribution of this species. Extensive conservation efforts are currently underway to protect additional areas of the Atlantic coastal rainforest, since it is home to a great number of species found nowhere else on the planet. The WWF is currently involved in community projects which seek to educate local people about the importance of protecting this forest. The US Agency for International Development (USAID) is working on reduced-impact forest management and on providing alternatives to slash-and-burn agroforestry. Conservation International (CI) is focussing on ecotourism as a possible alternative income for local communities which might otherwise have cleared areas of forest for agriculture. In 1998 a canopy walkway was built near the Una Biological Reserve, saving 320 acres of valuable rain forest habitat from logging. Efforts to translocate individuals from urban or agricultural areas to protected forest reserves appear to have been relatively successful so far. Extensive post-translocation monitoring has been carried out, which is providing important data about the species’ ecology and habitat requirements, as well as an indication of the success of the translocations themselves. Attempts to breed the species in captivity have not proved as successful. This is primarily due to the fact that these sloths do not survive for more than a few months outside of their natural environment. Research projects are focusing on the close relationship between females and offspring, so that breeding and re-introduction programmes in the future are better informed and more successful.

Further studies into the distribution, ecology and behaviour of this species in the wild are recommended. Additional reserves are required in areas of primary forest and secondary forest in which the species occurs. Protected areas need to be connected to minimise the genetic isolation of populations. Although maned sloths do not survive for more than a few months in captivity, they have been maintained in semi-captivity, so it may be possible to establish temporary populations in this manner (UNEP). Further genetic research is needed to determine whether the isolated populations represent distinct subspecies. In the meantime, the Edentate Specialist group recommends that any efforts for population management should recognize and preserve the unique genetic character of the three separate populations. In particular, individuals should not be translocated to novel, distinct populations.

Barros, M. C., Sampaio, I. and Schneider, H. 2003. Phylogenetic analysis of 16S mitochondrial DNA data in sloths and anteaters. Genetics and Molecular Biology 26(1): 5-11.

Chiarello, A., Lara-Ruiz, P. and Members of the Edentate Specialist Group. 2006. Bradypus torquatus. In: IUCN 2006. 2006 IUCN Red List of Threatened Species. Downloaded on 09 August 2006.

Edentata: The Newsletter of the IUCN Edentate Specialist Group 6. (Dec 2004).

Edentate Specialist Group. 1996. Bradypus torquatus. In: IUCN 2004. 2006 IUCN Red List of Threatened Species. Downloaded on 07 March 2006.

Lara-Ruiz, P. and Garcia Chiarello, A. 2005. Life-history traits and sexual dimorphism of the Atlantic forest maned sloth Bradypus torquatus (Xenarthra: Bradypodidae). Journal of Zoology 267(1): 63-73.

Nowak, R.M. 1999. Walker's Mammals of the World. Sixth edition. The Johns Hopkins University Press, Baltimore and London.

UNEP World Conservation Monitoring Centre

Villa-Lobos, J. 1998. Tree Top Walkway in Brazil . Biological Conservation Newsletter 176.

Distribution map based on data provided by the IUCN Global Mammal Assessment.