Brown-throated sloth
Brown-throated sloth
Brown-throated sloth

Common name: brown-throated sloth
Scientific name: Bradypus variegatus
Length: 42 to 80 cm
Weight: 2.25 to 6.3 kg (5 to 14 lb)
Population: unknown
Distribution: forests of South and Central America
Issue: habitat destruction
IUCN Red List status: least concern

The brown-throated sloth is one of four representatives of the family Bradypodidae, or three-toed sloths. It is characterized by a face and throat covered with dark brown fur, a dark band along each temple, and a small jaw. The rest of its body is grey-brown, with a slight greenish coloration due to the algae living it its fur, which helps its camouflage. The name “sloth” comes from its legendary sluggishness, caused by its slow metabolism. But the animal uses its slowness as a tactic to avoid being seen by predators.

One remarkable adaptation to almost always being suspended from branches on its four limbs in a “hammock” position is that its neck is extremely flexible, able to turn through nearly 270 degrees.

This sloth can be found near the “canopy” (the top of the forest), where it feeds on leaves, flowers and fruit. Because its diet has a low energy yield, it has trouble regulating its body temperature. It also has low muscle mass, a relatively weak heart, and a rather low heart rate. This is why it prefers dense forest canopies, where it can take advantage of the sun’s warmth and use branches and vines to move from tree to tree. In fact, it only descends from the trees to “do its business” about once every 10 days, an operation during which it can lose up to 30 percent of its body mass!

The brown-throated sloth therefore lives out its life almost entirely in the canopies of tropical forests, with the largest populations in the Amazon Basin. The mating season is poorly documented, but it is believed to take place before the rainy season. Males and females locate each other with an “ay ay” sounding call. Males seek out females in their trees, typically at about 15 metres off the ground. Mating lasts an average of 10 to 15 minutes, after which the male returns to its habitual slow business. A young sloth is born after a gestation period estimated at between five and eight months. The young clings to the mothers belly (in “hammock” position) for four months, until it is mature enough to hold onto branches, feed itself, and set off into the vast forest environment around it.

The lifecycle of the brown-throated sloth is poorly understood, but its lifespan is estimated to be between 30 and 40 years.

There are no persistent, long-term threats to the brown-throated sloth. Deforestation certainly kills the sloths that live in those forests, but their range is immense. Their population density is estimated at between two and eight individuals per hectare. Its natural predators are felines, eagles, and owls.

Did you know?
The brown-throated sloth rarely drinks. The liquid it takes in come almost exclusively from the plants it feeds on.

REFERENCES: Red List of Threatened Species of the International Union for Conservation of Nature (IUCN) and Encyclopedia of Life.

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