of the Amazon Rainforest or east of the Rio Negro, although its similarity to the pale-throated sloth found in these regions has led to some confusion in the past. It is found in many different kinds of environments, including evergreen and dry forests and in highly perturbed natural areas. It is generally found from sea level to , although some individuals have been reported from much higher elevations. Behaviour and diet Brown-throated sloths sleep 15 to 18 hours every day and are active for only brief periods of time, which may be during either the day or night. Although they can walk along the ground, and even swim, they spend most of their lives in the high branches of trees, descending once every eight days or so to defecate in the soil. The brown-throated sloths are cathemeral, with no preference for sleeping at day or night. Large, curved claws and muscles specifically adapted for strength and stamina help them to keep a strong grip on tree branches. They are able to withstand hanging inverted for extended periods of time due to fibrinous adhesions which attach their organs (such as their liver and stomach) to their lower ribs. Given that feces and urine can account for up to a third of their body weight, this adaptation prevents these organs from pressing on the lungs when hanging upside down, making breathing easier. Adult animals are solitary, except when raising young, and males have been observed to fight one another using their fore claws. Brown-throated sloths inhabit the high canopy of the forest, where they eat young leaves from a wide range of different trees. They do not travel far, with home ranges of only around , depending on the local environment. Within a typical, range, a brown-throated sloth will visit around 40 trees, and may specialise on one particular species, even spending up to 20% of its time in a single specific tree. Thus, although the species are generalists, individual sloths may feed on a relatively narrow range of leaf types. Although they get most of their fluids from the leaves that they eat, brown-throated sloths have been observed drinking directly from rivers. Sloths descend about once every eight days to defecate on the ground. The reason and mechanism behind this behavior have long been debated among scientists. There are at least five hypotheses: 1) fertilize trees when feces are deposited at