Bradypus torquatus, Illiger, 1811

Russell A. Mittermeier & Don E. Wilson, 2018, Bradypodidae, Handbook of the Mammals of the World – Volume 8 Insectivores, Sloths and Colugos, Barcelona: Lynx Edicions, pp. 118-132 : 131-132

4.

Maned Three-toed Sloth

Bradypus torquatus

French: Paresseux a criniere / German: Kragenfaultier / Spanish: Perezoso tridactilo de crin

Other common names: Brazilian Three-toed Sloth, Maned Sloth

Taxonomy. Bradypus torquatus Illiger, 1811 ,

type locality not given. Restricted by R. M. Wetzel and F. D. de Avila-Pires in 1980 to “the Atlantic drainage of Bahia, Espirito Santo, and Rio de Janeiro,” Brazil and further restricted by S. M. Vaz in 2003 to areas around Salvador, Bahia, Brazil.

Two distinct and disjunct phylogeographic groups of B. torquatus have been identified (a northern and a southern clade), but taxonomic distinctions need additional research. Monotypic.

Distribution. Discontinuous range in Coastal Atlantic Forests of E Brazil, from Sergipe and E Bahia S to S Espirito Santo, N Rio de Janeiro, and E Minas Geraisstates.

Descriptive notes. Head—body 590-752 mm, tail 40-54 mm, ear 8-22 mm, hindfoot 100-115 mm; weight 4.6-10.1 kg. Male Maned Three-toed Sloths are smaller in body mass and length than females. It is the largest species of extant Bradypus and is brown with long, coarse hair, often has mutualistic algae. Adult males and females have black manes around dorsal regions of neck, but they are longer and darker in males. Unlike other species of Bradypus , male Maned Three-toed Sloths do not have dorsal speculum. Chromosomal complement is 2n = 50 and FN = 64.

Habitat. Wet complex tropical forests, with most records from evergreen forests but some from semideciduous forests, at elevations up to 1000 m. Given limited dispersal behavior of the Maned three-toed Sloth, individuals have been detected in small forest fragments (20 ha). It is also found in regenerating secondary forests and shady agroecosystems.

Food and Feeding. The Maned Three-toed Sloth is a strict folivore. Leaves from 21 species of Neotropical plants (16 species of trees and five lianas) are consumed—a small proportion oftotal trees available, suggesting a selective diet. Micropholis venulosa ( Sapotaceae ), Mandevilla sp. ( Apocynaceae , a liana), Ficus sp. (Moraceae) , and Prunus sp. (Rosaceae) constitute the most important species. Like other sloths, Maned Threetoed Sloths prefer to eat young leaves, usually making up more than two-thirds of leaves an individual consumes.

Breeding. Timing of breeding of Maned Three-toed Sloths is based on a handful of observations. Young are born at the end of the rainy season (February-April), and births occur at regular twelve-month intervals. Infants consume leaves as early as two weeks old, but nursing continues until infants are 2-4 months old. At 9-11 months old, juveniles disperse from or are abandoned by their mothers; they disperse to establish their own home ranges.

Activity patterns. Maned Three-toed Sloths are largely arboreal. They spend ¢.75% of the day resting or sleeping, 12% feeding, and 11% moving. Autogrooming peaks in early morning, followed by increases in moving and foraging. These activities decline in the afternoon when resting increases. During the dry season (April-September), Maned Three-toed Sloths spend significantly less time resting and more time feeding compared with the wet season (October-March). They are active diurnally and nocturnally, although more regular activity occurs during the day. Nevertheless, at Poco das Antas Biological Reserve in Rio de Janeiro State, Brazil, Maned Three-toed Sloths were primarily nocturnal.

Movements, Home range and Social organization. Like congeners, Maned Three-toed Sloths climb slowly and positioning themselves on undersides of branches. During the day, individuals move an average of only 17 m (range 0-306 m); at night, they move even less, an average of 5 m (0-45 m). Maned Three-toed Sloths move an average of 24 m in 24 hours, but individuals are capable of longer forays, with the longest single movement recorded of more than 300 m in 5-5 hours. Similar to other species of three-toed sloths, individuals descend to the forest floor to defecate. Home ranges have been estimated at 2-8-5-9 ha.

Status and Conservation. Classified as Vulnerable on The IUCN Red List. Habitat loss and fragmentation are leading threats to the Maned Three-toed Sloth. It has a restricted distribution in the Atlantic Forest region, which is also one of the most populated areas of Brazil. Consequently, up to 90-95% ofthe forest has been lost, and what remains is highly fragmented. Potential available habitat for the Maned Three-toed Sloth is now less than 1000 km* and continues to shrink because of ongoing habitat loss and degradation.

Bibliography. Chiarello (1998a, 1998b), Hayssen (2009a), Hirsch & Chiarello (2012), Lara-Ruiz & Chiarello (2005), Lara-Ruiz et al. (2008), Moraes-Barros et al. (2006), Pinder (1993), Svartman (2012), Vaz (2003), Wetzel & de Avila-Pires (1980).

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Plate 6 Species Accounts

Distribution. Discontinuous range in Coastal Atlantic Forests of E Brazil, from Sergipe and E Bahia S to S Espirito Santo, N Rio de Janeiro, and E Minas Geraisstates.