The Pygmy Three-toed Sloth
The species
In 2001, the late researcher named Charles O. Handley Jr, and the young scientist Robert P. Anderson, published a paper that named the sloth of Isla Escudo de Veraguas “Bradypus pygmaeus, new species”. This decision was based on primarily it's significantly smaller size and the distinct coloration of its hair (or pelage). Since that paper, there has been little studied into how the life history traits of B. pygmaeus differ from the mainland three-toed sloth, B. variegates. However, given their dietary specialization on mangroves and evolution within the constrained habitat of these intertidal thickets, I suspect there are significant divergences.
The habitat
In a survey of red mangrove thickets, we found only a total of 10.67 hectors upon the island. These mangroves were clumped around the Northeastern side of the island, and often fragmented by upland forest or logging. They exists only in the brackish intertidal zone, in a heavy silt mud that can be waste deep or firm to walk on. Other then pygmy sloths, we observed eyelash vipers, iguanas, birds (including the Escudo hummingbird and Escudo wren), many many crabs, and a boa constrictor within the mangroves.
The island
Isla Escudo de Veraguas, Panama. This is small island (just 4.3 km2) is located 17.6 km into the Caribbean and lays within the indigenous Ngöbe-Buglé Comarca region of Panama. It is a low neotropical island of dense underbrush, mangrove swamps and a coral reef that wraps thickly around the Northern coast. Isla Escudo supports many endemic species including the pygmy three-toed sloth. There are a few small fishing camps that are occasionally inhabited by fishermen who come primarily to dive for lobster, which is sold to the neighboring Bocas del Toro region's tourist industry.
The human context
Isla Escudo is thought by some to be the mythic birthplace of the Ngobe people and has been visited only by them for decades. However, the diversity of Escudo de Veraguas has much to offer science. As the international scientific and conservation community, it is important for our continued presence to help conserve this diversity.
We can help by creating local economic incentive for the conservation of Escudo de Veraguas, and encourage its protection simply by employing the community’s resources for lodging, boat travel and local expertise during future research projects. The Ngöbe community, and especially those who fish on Escudo, are relatively impoverished. But they are a proud people, and I believe they could be great allies in protecting the island if it was made economically viable.
Observations on the Endemic Pygmy Three-Toed Sloth, Bradypus pygmaeus of Isla Escudo de Veraguas, Panama ́
Sam Kaviar#, Jakob Shockey#*, Peter Sundberg#
#* Corresponding author
# These authors contributed equally to this work.
Abstract
Our objective was to ascertain the population status of the Pygmy Three-toed Sloth, Bradypus pygmaeus, an IUCN Critically Endangered species, on Isla Escudo de Veraguas, Panama. Bradypus pygmaeus are thought to be folivorous mangrove specialists; therefore we conducted a visual systematic survey of all 10 mangrove thickets on the island. The total mangrove habitat area was measured to be 10.67 ha, comprising 0.024% of the total island area. The population survey found low numbers of B. pygmaeus in the mangrove thickets and far lower numbers outside of them. The connectivity of subpopulations between these thickets on the island is not established, as B. pygmaeus movement data is still lacking. We found 79 individuals of B. pygmaeus; 70 were found in mangroves and 9 were observed just beyond the periphery of the mangroves in non-mangrove tree species. Low population number, habitat fragmentation and habitat loss could lead to inbreeding, a loss of genetic diversity, and extinction of B. pygmaeus.