Since 2006, Bradypus pygmaeus has been listed as Critically Endangered on the IUCN Red List.
Pygmy Sloth Conservation Project
The pygmy sloth is an extraordinary, little-known mammal. It is part of a group of peculiar mammals, the Xenarthra, which includes the sloths, anteaters, and armadillos.
The pygmy sloth is the smallest of all three-toed sloth species. It is only found in Escudo de Veraguas, a tiny island located in the Caribbean of Panama. Little is known about this charismatic sloth that was only described as a new species in 2001. For example, there is no exact information on how many pygmy sloths remain, but due to its restricted distribution, the population is suspected to be quite small. Unfortunately, the pygmy sloth is affected by several threats, including the destruction of its habitat and the uncontrolled increase in tourist activities. This has led to its categorization as Critically Endangered.
Here we invite you to learn more about this incredible species and the efforts that are underway to save it from extinction.
Anatomical Characteristics
Bradypus pygmaeus
Common name: pygmy sloth.
Taxonomy: Mammalia > Pilosa > Bradypodidae > Bradypus > pygmaeus
• The pygmy sloth is the smallest sloth species. It was recognized as a new species in 2001, based on studies on its size and weight that differentiate it the closest species, Bradypus variegatus.
• A recent study published in 2019 concluded that the pygmy sloth from Escudo Island in Panama was a distinct species from B. variegatus, as described by Anderson and Handley in 2001 based on morphometric analyses.
• Like other three-toed sloths, the pygmy sloth has coarse, gray hair and a stripe of dark hair around the eyes.
• Adult males have a patch of shorter orange hair on their back known as a dorsal speculum.
• Adult pygmy sloths can be as long as 56-60 cm from the tip of the nose to the tail and they can weigh between 3 to 3.5 kg. Like all sloths of the Bradypus genus, this species has three large and distinct claws on its forelimbs.
• The pygmy sloth is the only sloth species where the phenomenon of insular dwarfism has led to speciation.
• The skull of the pygmy sloth is 12-16 % smaller than that of Bradypus variegatus.
• Preliminary genetic studies on pygmy sloths from the mangrove area indicate a very low level of diversity (N. de Moraes-Barros, University of Porto, Portugal, in litt., Voirin 2015). Additional research in population genetics, using larger samples from B. pygmaeus from around the island, are important to infer possible differences on levels of genetic diversity and endogamy correlated with habitat (mangrove and forest).
Conservation status
Since 2006, Bradypus pygmaeus has been listed as Critically Endangered on the IUCN Red List because it is living in a restricted area within an insular region, where habitat destruction menaces its survival.
It is listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
The pygmy sloth is listed as Critically Endangered (CR) in Panama, according to the list of threatened species published in 2016 by the Department of Protected Areas and Wildlife of the Ministry of Environment.
Among 100 mammal species listed as in danger of extinction, the pygmy sloth is 23rd on the EDGE (Evolutionary Distinct and Globally Endangered) Rank from the EDGE of Existence Programme of Zoological Society of London.
Biology and Ecology
• Like other sloth species, the green colored fur is due to the presence of algae, which allows pygmy sloths to camouflage among vegetation.
• At first, pygmy sloths were believed to inhabit only the red mangrove (Rhizophora mangle) area. Today, there is evidence indicating that pygmy sloths also use other tree species located near the red mangroves.
• Like other sloth species, the pygmy sloth is a great swimmer.
• Moths also inhabit the fur around the pygmy sloth’s body.
Population Trend
• There is no accurate information on how many B. pygmaeus individuals inhabit the island.
• According to the International Union for Conservation of Nature (IUCN), the pygmy sloth population is decreasing.
Geographical Distribution
• The pygmy sloth is an endemic species, meaning it can only be found on the island of Escudo de Veraguas in Panama.
• The island of Escudo de Veraguas has an area of about 430 ha (4.3 km2) and it is located in the Caribbean coast of Panama.
• This small island is about 17 km away from the coast and is one of the oldest islands in the Bocas del Toro archipelago, which formed approximately 9,000 years ago.
• The island of Escudo de Veraguas is also known as Degó, in Ngäbere language, because it is part of the Ngäbe- Buglé Indigenous District Heritage.
• The island’s name is not related to the Veraguas province, as it is part of the Bocas del Toro province.
Threats to Species Survival
• Habitat destruction, a result of recurrent timber harvest on the island, is the main threat to pygmy sloth survival. Increasing tourism and the exploitation of species image, poses an additional threat because it makes the pygmy sloth more vulnerable to wildlife trafficking. (Stop animal selfies)
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