Critically Endangered Species of the Week: the Pygmy Three-toed Sloth!

The Pygmy Three-toed Sloth, Bradypus pygmaeus. Picture source.

About:
    The Pygmy Three-toed Sloth, Bradypus pygmaeus, the smallest of all sloths, was only described as a separate species in 2011 [1,2,3]. The species likely evolved as a result of Island/Insular Dwarfism (e.g. Lomolino, 1985), due to the isolation of individuals of a mainland Panama population of Brown-throated Three-toed Sloths [2].
   The sloths have a tan-coloured face, with a dark band across the brow and usually orange eye patches. The back is often dark brown with a dorsal stripe. They also have long hairs on the sides of the head, giving the impression of a hood [2,3,4]. Individuals tend to weigh 2.5-3.5kg, and measure 48-53cm on average [2].
   Like all other three-toed sloths, they are arboreal mammals that feed on leaves. Uniquely, the Pygmy Three-toad Sloth is found exclusively in red mangroves, and feed on coarse leaves [2,4]. Again like other sloths their coats may appear green-tinged, due to the growing algae that serves as camoflage [2,3,4].

The Pygmy Three-toed Sloth, Bradypus pygmaeus. Picture source.

Number left in existence:
    Little is known of remaining population numbers, however it is estimated that the population consists of less than 500 individuals, and is declining [1,5]. Other estimates of 300, or 200 individuals have been proposed [5].


The small orange area shows the geographical range
of the Pygmy Three-toed sloth; Isla Escudo De Veraguas.

Geographical Range in the wild:   The Pygmy Three-toed Sloth is endemic to Isla Escudo de Veraguas, in the islands of Bocas del Toro, off the coast of Panama [1,2,3,4]. This gives the species a very isolated, restricted range of only around 4.3km squared [1]. Furthermore, the sloths have only been located in the red mangroves of the island, giving a range of 1.3-1.5km squared [1,4].

Why are they endangered:

• The island is thankfully uninhabited, however seasonal visitors (e.g. fishermen and local people) are known to hunt the sloths opportunistically [1,3].
• Studies such as Silva et al., 2010, suggest the species has a low level of genetic diversity, which may harm chances of survival if the population decreases any further [1].
• Indigenous people have been illegally cutting down the mangroves, reducing the available habitat and food for these sloths [1,3,4].
• Being so isolated, the species cannot disperse to other areas when under pressure from destruction of habitat and hunting [2].

What can we do to help?
    Thankfully Isla Escudo de Veraguas is protected as a wildlife refuge, contained within the Comarca Indigenous Reserve [1,4]. However much stricter enforcement of this protection is drastically required - the area receives little attention from wildlife protection authorities, as evidenced by the continued felling of the red mangroves [1,2]. Local awareness programmes are always required to encourage conservation of the species.

                           A video by ZSL EDGE, on their attempts to conserve the Pygmy Three-toed Sloth.

References:
1. http://www.iucnredlist.org/details/61925/0
2. http://en.wikipedia.org/wiki/Pygmy_Three-toed_Sloth
3. http://www.arkive.org/pygmy-three-toed-sloth/bradypus-pygmaeus/
4. http://www.edgeofexistence.org/mammals/species_info.php?id=1396
5. https://www.zsl.org/conservation/news/in-search-of-the-pygmy-sloth,960,NS.html
6. http://www.guardian.co.uk/environment/gallery/2012/sep/11/most-endangered-species-in-pictures#/?picture=395933529&index=1