Pygmy Sloth

The Pygmy Sloth is both the smallest and the most endangered sloth on the planet. There were only first discovered in 2001, and are found exclusively on the Isla Escudo de Veraguas, a small island off the coast of Panama. Their exact numbers are unknown, but estimates are less than 500 individuals.

Bradypus pygmaeus

Pygmy Sloths are smaller than other Sloths because they spent almost 10,000 years evolving in isolation on a small island. This biological process, called Insular Dwarfism, can also be seen in Florida's Key Deer and in Homo floresiensis from Flores Island, Indonesia. There are of course numerous other examples as well. Lack of space and a smaller supply of resources cause this evolutionary process to happen.

Like the Sloths on the mainland, Pygmy Sloths are arboreal, and feed off of leaves. Interestingly though, the Pygmy Sloths are found feeding near exclusively on Red Mangrove trees, which lives only near the island's coast. The Sloths have not been found in island forests. Their reliance on the Red Mangrove is one of the reasons for their decline; though the island is a marine reserve, indigenous people continue to harvest the plants.

Because Pygmy Sloths are so rare very little is known about their behavior. Detailed information on reproduction and parenting is not available, and scientists are only able to deduce information based on what other, larger Sloth species do. We do know, however, that they are solitary animals that live in a home-range of about 1.6Ha (4 Acres).

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IUCN Status : Critically Endangered

Location : Isla Escudo de Veraguas, Panama

Size : Weight up to 7.7lbs (3.5kg), Length up to 20in (51cm)

Classification : Phylum : Chordata -- Class : Mammalia -- Order : Pilosa
Family : Bradypodidae -- Genus : Bradypus -- Species : B. pygmaeus

Brown-throated Sloth

Bradypus variegatus

There are four species of Three-toed Sloth in the world, and the Brown-throated Sloth is the most common of the bunch. They can be found in different forested areas of Central and South America, typically living at elevations below 4,000ft.

Brown-throated Sloths can walk on the ground (kind of...), and they can even swim, but they spend almost all of their time up in the trees. They sleep as much as 18 hours a day, though 14-16 is more common. They are active the rest of the time, feeding and moving and protecting their territory, but only in 2-3 hour bursts.

The home range for a Brown-throated Sloth is pretty small-- only around a dozen acres. In this range they will move from tree to tree, feeding slowly on different leaves and fruits. Their metabolism is so slow that it can take a month to digest a single meal! In fact, the Sloths will usually only descend from their arboreal homes in order to go to the bathroom. This happens only once every eight days!

Brown-throated Sloth

Brown-throated Sloths have some interesting anatomical features, including their hair-- each follicle has multiple cracks on the surface. These cracks are the prefect places for algae to grow. The algae get a nice host to live on, and the Sloths get some extra camouflage. But the algae aren't the only passengers that the sloth has. A species of moth, Cryptoses choloepi lives in the Sloth fur and lays its eggs in the Sloth's dung.

Other strange anatomy facts? Brown-throated Sloths have 10 cervical vertebrae, and can rotate their necks 270 degrees. They also have a lot of trouble regulating their body temperature due in part to their small hearts and lack of muscle mass. This is why Sloths are only found in tropical warm areas.

Females sloths will make loud vocalizations in order to attract a mate. A male will come to her, and she will usually mate with the first one to show up. After copulation the male leaves, and the female goes through the 5-8 month gestation period alone. They give birth either on the ground or in trees, and the young sloth will cling to its mother's underside for up to 5 months. They wean quickly but stick around for much longer to learn important Sloth skills from mom, including motor skills and which leaves are best to eat.

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IUCN Status : Least Concern
Location : South and Central America
Size : Length up to 31in (80cm), Weight up to 14lbs (6.3kg)

Classification : Phylum : Chordata -- Class : Mammalia -- Order : Pilosa
Family : Bradypodidae -- Genus : Bradypus -- Species : B. variegatus

Giant Anteater

Myrmecophaga tridactyla

Giant Anteaters are a relatively new addition to my "Favorite Animals" list. First off, they're huge. Secondly, they have awesome tails. Thirdly, their babies hang on to their tails. And finally, I am a sucker for animals with long faces (which is probably why I own a Collie).

There are four species of Anteater, all of which can be found in the Western Hemisphere. The Giant Anteater is (un-shockingly) the largest of the bunch, and by quite a substantial amount. A full grown adult can weight well over 100lbs, while it's next largest cousin doesn't typically go over 15.

Giant Anteater

They are also really, really long. They have body lengths of around 4ft, and then a 3ft long tail after that. Their tails are also really brush-like, and help them to balance while standing up on their hind legs to feed. Giant Anteaters don't actually walk flat-footed, they curl up their paws into fists and walk on their knuckles. This keeps their long claws nice and sharp for digging.

Giant Anteaters have additional tools that help them find and slurp up prey. They have poor eyesight,a dn rely on smell to locate mounds. Once they find and dig in to a mound, they use their two foot long tongue to probe inside and collect lots and lots of ants and termites in their sticky saliva. They can flick their tongues 160 times per minute! The Anteater then uses its long jaw to detahc the meal, and its powerful stomach to grind up and break down the insects. They can consume up to 30,000 in a single day!

Giant Anteaters are solitary animals, unless they are a female with a child. Young Anteaters stay with thier mothers for as long as two years, and will ride on their backs and tails when they are small. This not only allows the little family to get around quicker, but it keeps the young one safe since its patterning camouflages it into the mother's fur. For some really, really cute pictures, check out Maripi and Pablo's gallery at the National Zoo website.

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IUCN Status : Vulnerable

Location : Central and South America

Size : Body length 4ft (1.2m), Weight up to 140lbs (64kg)

Classification : Phylum : Chordata -- Class : Mammalia -- Superorder : Xenarthra
Order : Pilosa -- Family : Myrmecophagidae -- Genus : Myrmecophaga -- Species : M. tridactyla