Inferences of the Ecological Habits of Extinct Giant Sloths from the Brazilian Intertropical Region

Three indices estimated from measurements of the humerus and ulna were used to suggest possible ecological habits of eight extinct giant sloths from the Late Pleistocene of the Brazilian Intertropical Region. To make these inferences, data from extant primates and xenarthras representing suspensory, climbing and digging forms were compared. The results indicate niche differentiation existed between these species; Ahytherium aureum, Australonyx aquae and Nothrotherium maquinense could have been climbers, Catonyx cuvieri, Ocnotherium giganteum and Glossotherium phoenesis were diggers, while Valgipes bucklandi and Eremotherium laurillardi were strictly terrestrial in their habits. These results suggest a general pattern in which members of the Megalonychidae and Nothotheriidae were mainly climbers, whereas mylodontines were mainly diggers, and scelidotheres were strictly terrestrial along with members of the giant Megatheriidae.