What is a Sloth?
Sloths come from one of the earliest mammalian orders, Xenarthra, and originated about 35 million years ago in the Late Eocene of South America. They are most closely related to armadillos and anteaters. Today, only two genera of sloths with five species exist in South America, whereas there used to be over thirty-five genera of the extinct ground sloths ranging from parts of Antarctica, South America, Central America, Hispaniola, and North America with some even going as far as Alaska. The extinct sloths also varied in body size from about 1 meter (equaling living sloth size) all the way up to elephant sized in the largest genus, Megatherium. The two modern genera of sloths are Bradypus (Brad-e-pus), the three-toed sloths, and Choloepus (Co-lee-pus), the two-toed sloths. The number of toes is only indicative of the forefoot as the hind feet of both genera have three toes. Though both of the living genera of sloths look similar, live in the trees, and have a suspensory mode of movement, they are not related. Bradypus is most closely related to the family Megatheriidae and Choloepus to the family Megalonychidae.
Modern sloths live upside-down in the forests of South America. Despite their long, sharply curved claws, they are herbivores and mainly eat tree leaves as their teeth are too primitive and weak, due to a lack of enamel, to chew anything else. The claws are part of their adaptation to life in the trees and help them remain sleeping and suspended underneath branches for hours. Sloths are generally nocturnal and move around little when awake. When they do move, it is at a slow and deliberate speed. This slow way of life is necessary to navigate the web of small peripheral tree branches where they feed and is further reflected in their rate of metabolism. Sloths take their sweet time digesting food and consequently, only defecate once or twice in a one week period. The defecation usually takes place at the base of tree where the sloth excavates a spot for it with its short, stubby tail. This event marks one of the rare occasions that sloths will venture to the ground.
The slow or low rate of metabolism in sloths effects their ability to fight off
illness. Most sloths have difficulty surviving when in captivity outside
of their natural range because they cannot fight off new diseases or adapt to a
colder climate. This is unfortunate as three-toed sloths make decent pets, though their status as an endangered species further deters the notion of
obtaining one outside of South America. Two-toed sloths, however, would
make for poor companions as they tend to have a mean-streak and are quick to
bite with their self-sharpening canines.
MORE TO COME....
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