Most of the common names like sloth or perezoso, as well as its scientific name “Bradypus” from the Greek for slow feet, refer to the monotony of the movements and sluggishness of the members of this family (Cabrera, 1940).
The head is round, hardly differentiated from the remarkably long and mobile neck. The body is thick-set, short, and with great mobility of the vertebral column; the arms are slender and very long, a full third longer than the legs; the tail is short and stubby.
The whole animal is covered with long coarse but soft and silky hair, which serves as a thatch in rain and with the dense under fur, as a real protection against the attack of many foes. The general colour of this species is grizzled drab, with irregular patches of dirty white on the dorsal surface. The males are highly coloured for mammals, having bright orange ear patches and a rounded spot of the same colour in the middle of the back.
Very rarely an adult female sloth will have dull orange ear patches, but never the brilliant back marking (Beebe,1926).
The pale-throated sloth can be distinguished from other species of sloth by its paler throat (white or yellowish buff) in combination with the pale forehead and the lack of dark facial marks (Gardner, 2007).
The neck contains nine cervical vertebrae.
The forelimbs are slightly longer than the hind limbs and each forefoot has three long claws.
The sloth’s digits are bound together with gristle and flesh so the claws are fairly immoveable; the strong sharp claws are almost semicircular, measuring up to about 7.5 cm (Merret, 1983).