Bradypus pygmaeus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Pilosa Bradypodidae

Scientific Name: Bradypus pygmaeus Anderson & Handley, 2001
Common Name(s):
English Pygmy Three-toed Sloth
Spanish Perezoso Pigmeo
Taxonomic Notes: Bradypus pygmaeus has only recently been described by Anderson and Handley (2001) as a separate species.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B1ab(ii,iii)+2ab(ii,iii) ver 3.1
Year Published: 2014
Date Assessed: 2013-10-06
Assessor(s): Voirin, B., Smith, D., Chiarello, A. & Moraes-Barros, N.
Reviewer(s): Abba, A.M. & Superina, M.
Contributor(s): Anderson, R.P.
Facilitator/Compiler(s): Superina, M.
Bradypus pygmaeus is listed as Critically Endangered as this species has a very restricted range, being found only on one very small island less than 5 km² in size, and there is likely a continuing decline in the quality of habitat and area of occupancy due to habitat degradation.
Previously published Red List assessments:

Geographic Range [top]

Range Description:Bradypus pygmaeus is known only from Isla Escudo de Veraguas, in the islands of Bocas del Toro, Panama. Sloths on the younger islands of the Bocas del Toro archipelago are conspecific with Bradypus variegatus. Isla Escudo de Veraguas has an area of approximately 4.3 km² and is about 17.6 km from the mainland of Panama.
Countries occurrence:
Additional data:
Estimated area of occupancy (AOO) - km2:4Continuing decline in area of occupancy (AOO):Yes
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:4.3
Continuing decline in extent of occurrence (EOO):NoExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:1Continuing decline in number of locations:No
Extreme fluctuations in the number of locations:No
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:There is no accurate information available on the total population size of B. pygmaeus. Previous censuses only searched for sloths in mangroves, which comprise less than 3% of the island. Bradypus pygmaeus has been observed in the interior forests of the island; however, censusing cryptic, slow moving arboreal mammals in dense forest is challenging and limited. For instance, a census carried out on existing mangrove tracts in Isla Escudo de Veraguas (0.02% of the island area) sighted a total of 79 individuals, 70 of which were in the mangroves and nine in non-mangrove trees in the periphery of the mangroves (Kaviar et al. 2012). However, no estimates on the total island population were made; the population is likely to be relatively small. In the mangroves the population density of this sloth is relatively high (5.8 sloths/ha).
Current Population Trend:Decreasing
Additional data:
Extreme fluctuations:NoPopulation severely fragmented:No
All individuals in one subpopulation:Yes

Habitat and Ecology [top]

Habitat and Ecology:This smallest of all sloths is found both in mangrove patches and on the interior of Isla Escudo. Although previously thought to exclusively inhabit the red mangroves of the island, recent tracking studies have found the sloths on the interior of the island, in dense tropical rainforest. Because of the difficulty of censusing cryptic canopy mammals, their density and abundance in the thicker forests is unknown. Nothing is known about their reproduction, lifespan, home range, or diet, although it is suspected that it primarily, if not exclusively, feeds on mangrove leaves. Its population is likely larger than previously estimated, but is still limited due to its restricted habitat range.
Continuing decline in area, extent and/or quality of habitat:Yes

Use and Trade [top]

Use and Trade: The species is not utilized. Although it was previously thought that locals would eat pygmy sloths, this was recently disproven.

Threats [top]

Major Threat(s): Although the island is uninhabited, there are seasonal visitors (fishermen, campesinos, lobster divers, tourists, and local people) who harvest timber to maintain wooden houses on the island. Preliminary studies suggest a reduced level of genetic diversity for pygmy sloths compared to its putative population of origin, the common sloth population from mainland Panama. This is expected, considering the history of species diversification and isolation on the island. However, signs of a more recent population bottleneck were also detected (Silva et al. 2010, N. Moraes-Barros pers. comm. 2013). These results highlight the need of a continuous evaluation of the population status, trends, and additional studies considering a possible scenario of endogamic depression if the (already low) population size decreases any further.

Despite having been designated as a protected landscape through a governmental resolution in 2009, a number of domestic and international efforts have been mounted to develop tourism infrastructure on the island. This includes plans for an eco-lodge, a casino, a marina, and a banking centre. The current status of the island’s custody is vague; a governmental resolution, and thus the protected status of the island, cannot be revoked, but no government staff has been appointed specifically to enforce protection of the island. Ongoing disagreements between the local Ngäbe bugle Comarca, regional politicians, and the Panamanian government are further complicating long-term protection of the island and the pygmy sloths. Additionally, as pygmy sloths have become more widely recognized internationally, there is growing interest in collecting them for captivity.

Conservation Actions [top]

Conservation Actions: Bradypus pygmaeus is endemic to a single island of Panama, which is protected as a wildlife refuge and is contained within the Ngäbe bugle Comarca. There is a need to improve the enforcement of this protected area. A comprehensive conservation plan is underway, bringing together the local community, wildlife authorities in Panama, and the national and international scientific community to protect the island, using the pygmy sloth as a flagship species.

The pygmy sloth is listed on CITES Appendix II (Notification to the Parties 2013/052, 20 November 2013).

Classifications [top]

1. Forest -> 1.6. Forest - Subtropical/Tropical Moist Lowland
suitability:Unknown season:resident 
1. Forest -> 1.7. Forest - Subtropical/Tropical Mangrove Vegetation Above High Tide Level
suitability:Suitable season:resident major importance:Yes
2. Land/water management -> 2.1. Site/area management
3. Species management -> 3.1. Species management -> 3.1.1. Harvest management
4. Education & awareness -> 4.3. Awareness & communications
5. Law & policy -> 5.4. Compliance and enforcement -> 5.4.2. National level
5. Law & policy -> 5.4. Compliance and enforcement -> 5.4.3. Sub-national level

In-Place Research, Monitoring and Planning
  Systematic monitoring scheme:Yes
In-Place Land/Water Protection and Management
  Conservation sites identified:Yes, over entire range
  Occur in at least one PA:Yes
In-Place Species Management
  Harvest management plan:No
  Successfully reintroduced or introduced beningly:No
  Subject to ex-situ conservation:No
In-Place Education
  Subject to any international management/trade controls:Yes
1. Residential & commercial development -> 1.3. Tourism & recreation areas
♦ timing:Future ♦ scope:Unknown ♦ severity:Unknown ⇒ Impact score:Unknown 
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

5. Biological resource use -> 5.1. Hunting & trapping terrestrial animals -> 5.1.1. Intentional use (species is the target)
♦ timing:Ongoing ♦ scope:Minority (<50%) ♦ severity:Negligible declines ⇒ Impact score:Low Impact: 4 
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

5. Biological resource use -> 5.3. Logging & wood harvesting -> 5.3.5. Motivation Unknown/Unrecorded
♦ timing:Ongoing ♦ scope:Unknown ♦ severity:Unknown ⇒ Impact score:Unknown 
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

1. Research -> 1.1. Taxonomy
1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.3. Life history & ecology
1. Research -> 1.5. Threats
1. Research -> 1.6. Actions
2. Conservation Planning -> 2.1. Species Action/Recovery Plan
2. Conservation Planning -> 2.2. Area-based Management Plan
3. Monitoring -> 3.1. Population trends
3. Monitoring -> 3.3. Trade trends
3. Monitoring -> 3.4. Habitat trends
0. Root -> 4. Other

Bibliography [top]

Aguiar, J.M. and da Fonseca, G.A.B. 2008. Conservation status of the Xenarthra. In: S.F. Vizcaino and W.J. Loughry (eds), The Biology of the Xenarthra, pp. 215-231. University Press of Florida, Gainesville, Florida.

Anderson, R.P. and Handley Jr., C.O. 2001. A new species of three-toed sloth (Mammalia: Xenarthra) from Panama, with a review of the genus Bradypus. Proceedings of the Biological Society of Washington 114: 1-33.

Anderson, R.P. and Handley Jr., C.O. 2002. Dwarfism in insular sloths: biogeography, selection, and evolutionary rate. Evolution 56: 1045-1058.

Baillie, J. and Groombridge, B. (comps and eds). 1996. 1996 IUCN Red List of Threatened Animals. IUCN, Gland, Switzerland and Cambridge, UK.

Chiarello, A.G. 2008. Sloth ecology: an overview of field studies. In: S.F. Vizcaíno and W.L. Loughry (eds), The Biology of the Xenarthra, pp. 269-280. University of Florida Press, Gainesville, FL, USA.

Gardner, A.L. 2005. Order Pilosa. In: D.E. Wilson and D.M. Reeder (eds), Mammal Species of the World, pp. 100–103. The Johns Hopkins University Press, Baltimore, Maryland, USA.

Gardner, A.L. 2007. Magnorder Xenarthra. In: A.L. Gardner (ed.), Mammals of South America, pp. 127-176. The University of Chicago Press, Chicago.

Hayssen, V. 2008. Bradypus pygmaeus (Pilosa: Bradypodidae). Mammalian Species 812: 1-4.

IUCN. 2014. The IUCN Red List of Threatened Species. Version 2014.1. Available at: (Accessed: 12 June 2014).

Kaviar, S., Shockey, J. and Sundberg, P. 2012. Observations on the endemic pygmy three-toed sloth, Bradypus pygmaeus of Isla Escudo de Veraguas, Panama. PLoS ONE 7(11): e49854.

Silva, S., Voirin, B., Ferrand, N., Morgante, J.S. and Moraes-Barros, N. 2010. The common and endangered Bradypus sloths - is there a correlation between genetic diversity and endangered species? 24th International Congress for Conservation Biology. Edmonton, Alberta, Canada.

Citation: Voirin, B., Smith, D., Chiarello, A. & Moraes-Barros, N. 2014. Bradypus pygmaeus. The IUCN Red List of Threatened Species 2014: e.T61925A47444229. . Downloaded on 22 September 2018.
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