Pygmy Three-toed Sloth
(Bradypus pygmaeus)
The pygmy three-toed sloth was only recognised as a distinct species in 2001. It can only be found on Isla Escudo de Veraguas which has been separated from mainland Panama for 9,000 years. Famous for its slow movements the pygmy three-toed sloth is ideally suited to life in the mangroves and is surprisingly good at swimming. The major threat to the pygmy three-toed sloth is habitat destruction which is reducing the size of its already small habitat.
Urgent Conservation Actions
Law enforcement needs to be improved and community education initiated.
Panama, but found only on the small island Isla Escudo de Veraguas.
Associated Blog Posts
12th May 15
Two years have passed since my first encounter with a female pygmy sloth and her  baby on Escudo de Veraguas Island. With so little information about this...  Read

11th Jun 13
EDGE Fellow Diorene isn't afraid to wade up to her chest in search of a sloth! Read her latest blog about her adventures in Panama: My country, Panama, i...  Read

2nd Aug 12
A big thank you to all our supporters who donated and spread the word about our campaign – each of you helped us to raise a grand total of £3,653 which we...  Read

27th Jul 12
Our two EDGE scientists David and Craig had battled bad weather and stormy seas to get a glimpse of the elusive pygmy three-toed sloth on Escudo Island. The...  Read

24th May 12
In the last blog David and Craig had arrived in Panama City, met their chef Gustavo and boat captain Sebastian, and had gathered all the equipment they neede...  Read

24th May 12
The pygmy three-toed sloth was officially recognised as a distinct species in 2001. Along with armadillos and anteaters, sloths are members of the superorder...  Read

11th Apr 12
After 13 months of project planning, fund raising and reviewing the available literature, Craig Turner and I were at the stage of actually procuring equipmen...  Read

11th Mar 11
While on holiday in Panama, David Curnick, a member of the Marine and Freshwater team at ZSL and sloth enthusiast met with Bryson Voirin who has spent the la...  Read

Evolutionary Distinctiveness
Order: Pilosa
Family: Bradypodidae
Together with armadillos and anteaters, sloths make up the Neotropical superorder Xenarthra. Sloths are the most diverse Xenarthra group with almost 100 genera described. These are the only placental group with living representatives from the initial South American mammalian stocks. This huge diversity was present in the Americas during the Pleistocene, but was extremely reduced about 10,000 years ago when many mammal species became extinct. Nowadays, there are only six extant sloth species from two genera: Bradypus (three-toed sloths) and Choloepus (two-toed sloths).

Isla Escudo, where the pygmy sloth is found today, only became isolated from mainland Central America 8900 years ago, as sea levels rose after the end of the last Ice Age glaciation. The pygmy sloth has therefore undergone extremely rapid body size evolution following the isolation of its founder population in the early Holocene Epoch.
Head and body length: 485 – 530 mm
Weight: 2.5 – 3.5 kg

The smallest of the three-toed sloths, the pygmy three-toed sloth is characterised by pale grey-brown fur that is often blotchy and a tan-coloured face with a distinctive dark band around the eyes. Long, shaggy hair hangs over the face, giving a hooded appearance. Male adults have a bright orange patch on their back through which a black band runs vertically. Sloths have an unusual means of camouflage to avoid predation; their outer fur is often coated in algae, giving the hair a greenish colour that helps conceal them in their forest habitat. Three-toed sloths (Bradypus) can be distinguished from their distant relatives, the two-toed sloths (Choloepus), by the three digits on their forelimbs, blunter muzzle, and simpler, chisel-shaped teeth.

Sloth fore-arms are much longer than their thighs, so when on the ground they crawl on their elbows rather than their hands and their thighs are spaced so widely that they cannot bring their knees together. Although this makes it difficult for the pygmy three-toed sloth to move along on the ground their hands and feet have long, curved claws that let them hang upside down in trees all day long with ease. Their specialised neck allows them to turn their head approximately 270o horizontally and observe all around without having to move the rest of their body. A further adaptation to living upside down is that sloth hair grows in the opposite direction of the hair of most animals, which makes it easier for water to run off away from the skin when the animal is upside down.

It is thought that the pygmy three-toed sloth primarily feeds on the leaves of the red mangrove trees in which it lives. Sloths move slowly using a hand over hand motion to move along upside down beneath branches as well as up and down vertically and are able to move much more easily in the trees than on the ground. Sloths usually only descend to the ground when they need to urinate and defecate and can go for up to seven days without needing to defecate. Since their movements are so slow, the pygmy three-toed sloths main forms of defences are camouflage and stealth, whereby they avoid predation largely by avoiding detection. However, they often survive attacks due to their tough hides, strong grips and a remarkable healing ability.

Their small home ranges average 1.6 Ha which is suitable for their lives as solitary individuals. Adults only come together to mate, finding each other using loud calls. Although the gestation period for the pygmy three-toed sloth is unknown, other species of three-toed sloth are pregnant for between 4 and seven months before giving birth. The mother bears one infant at a time, and will care for it between six months or a year during which time she will carry the young sloth with her everywhere she goes.

The green algae found in the fur of the pygmy three-toed sloth is a unique species of Trichophilus algae which is thought to be symbiotic, providing camouflage to the sloth at no detriment to the sloth’s health. Algae begin to grow on the pygmy three-toed sloth during childhood and are probably transferred from mother to child.
Found exclusively in red mangrove forests surrounding the island where the land meets the sea. These mangroves are thought to cover an area of just 1.3-1.5 km2 on the island.
Known only from the small island Isla Escudo de Veraguas which lies about 17km from mainland Panama.
Population Estimate

Unknown, population numbers thought to be fewer than 500.

Population Trend
Classified as Critically Endangered (CR B1ab(ii,iii)) on the 2010 IUCN Red List of Threatened Species.
The most serious threat to the pygmy three-toed sloth is the destruction of mangroves in which they live. There are reports of mangrove trees being cut down on Isla Escudo de Veraguas which not only destroys the trees in which this species live but also reduces the size of an already small area of habitat in which the pygmy thee-toed sloth prefers to reside. Visitors to the island which is home to a small number of people may also be hunting the pygmy three-toed sloth and if development was carried out to support a larger human population or tourism there would be further destruction to the mangrove habitat.
Conservation Underway

Isla Escudo de Veraguas has been designated as a protected area and is located within the Ngobe-Bugle comarca which means the local indigenous people have strong administrative power.


A group of scientists from ZSL went out to Escudo to conduct an extensive population survey of the pygmy sloths in March 2012. In total they encountered 72 sloths and observed some mangrove cutting, estimating that there may be fewer than 100 individuals within mangrove habitats, but that more sloths may be present in dense forest. At present a campaign is being run to raise funds to develop a participatory conservation strategy for the pygmy sloth that involves all stakeholders.


This project supports in-country EDGE Fellows to help conserve relevant EDGE species

To significantly increase the protection and awareness of Isla Escudo de Veraguas as a unique habitat using pygmy three-toed sloths as a flagship species through long-term collaborations with Panamanian authorities and local communities.

Conservation Proposed

Law enforcement within the reserve is inadequate and needs to be strengthened to protect this species. Conservation could also be improved through local awareness programmes, specifically those promoting sloths as conservation flagship species. Education of local communities is vital to stopping poaching problems as well as reducing deforestation and increasing law enforcement within the reserve.

Associated EDGE Community members

Marine and freshwater programme coordinator at ZSL with a passion for mangroves and corals

I am veterinarian and I am working with the pygmy three-toed sloth on Escudo de Veraguas Island in Panama.


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

Anderson, R.P. and Handley, C.O. Jr. 2001. A new species of three-toed sloth (Mammalia:Xenarthra) from Panamá, with a review of the genus Bradypus. PBiol Soc Wash. 114(1):1-33.

Bezerra, B.M. et al. 2008. Observation of brown-thraoted three-toed sloths: mating behaviour and the simulataneous nurturing of two young. J. Ethol 26:175-178

De Moraes-Barros, N. et al. 2006. Comparative phylogeography of the Atlantic forest endemic sloth (Bradypus torquatus) and the widespread three-toed sloth (Bradypus variegatus)(Bradypodidae, Xenarthra). Genetica 126:189–198.

Diniz, L. and Oliveira, P. 1999. Clinical problems of sloths (Bradypus sp. And Choloepus sp.) in captivity) 30:1:76-80

Hanging with the Sloth Guidebook

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

Robert P., et al. 2001. A new species of three-toed sloth (Mammalia: Xenarthra) from Panama, with a review of the genus Bradypus. Proceedings of the Royal Soc of Washingtion 114(1):1-33.

Samudio, R. & Members of the IUCN SSC Edentate Specialist Group 2008. Bradypus pygmaeus. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. <www.iucnredlist.org>. Downloaded on 09 November 2010.

Suutari, M. et al. 2010. Molecular evidence for a diverse green algal community growing in the hair of sloths and a specific association with Trichophilus welckeri (Chlorophyta, Ulvophyceae).10:86

Taube, E. et al. 2001. Reproductive biology and postnatal development in sloths, Bradypus and Cholepus: review with original data frm the field (French Guiana) and from captivity. Mammal Rev. 31:3:173-188

if you can provide new information to update this species account or to correct any errors, please email us at info@edgeofexistence.org

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