The maned three-toed sloth (Bradypus torquatus) is an incredible mammal which spends most of its life in the branches of trees, either hanging upside down or sitting in a fork. It even searches for food and eats while upside down. It is so well adapted to its upside-down lifestyle that its fur grows in the opposite direction to that of most mammals! The largest of the three species of sloth, the maned three-toed sloth is named after its long mane of black hair, which runs down the back of the neck and over the shoulders. The rest of the coat is a greyish-brown colour, although it frequently has a greenish tinge because of the algae that live in the hair. This algal growth provides the species with excellent camouflage, enabling it to blend in perfectly with the trees in which it lives.
Whereas most mammals have seven neck vertebrae, three-toed sloths have eight or nine. This makes their necks far more flexible so that they can turn 270 degrees, allowing them to find food all around them when up on a tree. Sloths spend practically their entire lives in the trees. These sloths don’t have any biting teeth, so instead they rip their leaf-food with their lips. Sloths are, as you may have guessed, very slow in nature: their slow metabolic rate is about half of that of most mammals, and they sleep for around 15 hours a day. They only descend to the ground about once or twice a week to urinate and defecate, and on occasion to move from one tree to another. Sloths might be well camouflaged in the trees, but they are extremely vulnerable on the ground where they move by crawling slowly on their soles and forearms.
The maned sloth is the most threatened sloth species, because it is only found in the Atlantic coastal rainforest of Brazil; this habitat covers a small area, is disturbed and fragmented, and is getting rapidly smaller as a result of logging, charcoal production, and clearance for plantations and cattle pasture. The large gaps in the forest mean that some populations may already be extremely small. Today, the Atlantic forest is reduced to less than 10% of its original area, and this region has the highest human population in Brazil so the pressure on the forest is high.