Bradypus pygmaeus, Anderson & Handley, 2001

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

2.

Pygmy Three-toed Sloth

Bradypus pygmaeus

French: Paresseux nain / German: Zwergfaultier / Spanish: Perezoso tridactilo pigmeo

Other common names: Pygmy Sloth

Taxonomy. Bradypus pygmaeus R. P. An- derson & Handley, 2001 ,

“Panama: Bocas del Toro: Isla Escudo de Veraguas, West Point.”

Taxonomic status unclear; it was described as a species based on morphometric analyses, notably a smaller body size, but results of recent molecular studies are conflicting and could be a pygmy form of B. variegatus . Monotypic.

Distribution. Restricted to the Escudo de Veraguas I, 18 km offshore from the Valiente Peninsula, on the Caribbean coast of Panama.

Descriptive notes. Head-body 485-530 mm, tail 45-60 mm, ear 10 mm, hindfoot 94-110 mm; weight 2:5.3-5 kg. The Pygmy Three-toed Sloth is similar in color to the Brown-throated Three-toed Sloth ( B. variegatus ); it is gray with long, coarse hair, covered with algae causing hair to appear green. The Pygmy Three-toed Sloth has dark orbital stripe over lighter colored and browner face. Males have dorsal speculum of shorter cream to orange hair. Forelimbs and hindlimbs have three large and distinct claws.

Habitat. [sland mangrove forests. Pygmy Three-toed Sloths are believed to be primarily associated with red mangroves ( Rhizophora mangle, Rhizophoraceae ) that occur along the margins of Isla Escudo de Veraguas. A few sloths have been observed in interior, upland forests of the island. More systematic efforts are needed to survey interior forests to determine the degree to which Pygmy Three-toed Sloths are associated with mangrove and other tree species.

Food and Feeding. The Pygmy Three-toed Sloth has been observed eating leaves from mangroves and other species (e.g. Cecropia spp. , Urticaceae ).

Breeding. No information.

Activity patterns. Pygmy Three-toed Sloths are largely arboreal, but terrestrial and even swiming locomotion has been recorded.

Movements, Home range and Social organization. One study of Pygmy Three-toed Sloths systematically searched all mangrove stands (10-7 ha in total on the island) and located 79 individuals for a density of 7-4 ind/ha. The island is 430 ha, butit is unknown to what extent upland forests are used by Pygmy Three-toed Sloths. A study recently compared sleep characteristics between Pygmy Three-toed Sloths and Brown-throated Three-toed Sloths and found that while both species slept for the same amount of time (9-10 hours/day), the Brown-throated Three-toed Sloth preferred to sleep at night; Pygmy Three-toed Sloths showed no preference. It was suggested that the difference could be the result of different predation risk, with island Pygmy Three-toed Sloths being exposed to less risk than mainland Brown-throated Three-toed Sloths.

Status and Conservation. CITES Appendix II. Classified as Critically Endangered on The IUCN Red List. Given the extremely limited distribution of the Pygmy Three-toed Sloth on a single, small island and uncertainty around the overall population size, exact distribution, and threats of habitat loss from visitors to the island, the viability of the population is unclear.

Bibliography. Anderson & Handley (2001), Hayssen (2008), Kaviar et al. (2012), Voirin (2015), Voirin et al. (2014).

Figures

Plate 6 Species Accounts

Distribution. Restricted to the Escudo de Veraguas I, 18 km offshore from the Valiente Peninsula, on the Caribbean coast of Panama.