In different parts of its range, Bradypus variegatus (Fig. 1) is sympatric with both two-toed sloths, Linnaeus's two-toed sloth (Choloepus didaetylus) and Hoffmann's twotoed sloth (Choloepus hoffmanni). The faces of the 2 genera have striking visual differences: the face of Choloepus is much more elongated, with a more-promient fleshy nose, whereas that of Bradypus is much blunter. B. variegatus has 3 digits on the manus that are partially fused and hairy volar pads, whereas both Choloepus have only 2 unfused digits and hairless volar pads (Mendel 1985). In addition, B. variegatus has 8 or 9 cervical vertebrae compared with 6 in C. hoffmanni (Mendel 1985). Compared with the pale-throated sloth (B. tridaetylus), B. variegatus has a brown throat (that of B. tridactylus is yellow) and lacks distinct foramina in the anterodorsal nasopharynx (present in B. tridaetylus-Wetzel and Avila-Pires 1980). The color differences are variable and in areas of overlap (especially northern Brazil) the 2 species are difficult to distinguish. B. variegatus lacks the black mane on the neck and shoulders of the maned sloth (B. torquatus-Wetzel and Avila-Pires 1980). B. variegatus is generally larger in size (total length >535 mm) than the pygmy three-toed sloth (B. pygmaeus-total length <535 mm) and has a more robust skull. The coronoid process of the mandible (Fig. 2) for B. variegatusis thick, whereas that of B. pygmaeus is thin and falcate (Anderson and Handley

2001). B. variegatus, B. tridactylus, and B. torquatus are broadly similar in size.