Habitat: Lowland evergreen and deciduous forests. Distribution: Honduras to Argentina and Paraguay. Common, and extensively studied, on Barro Colorado Island, Panama. Natural History Notes: A slow-moving, arboreal herbivore that feeds on the leaves of Cecropia and other tropical trees. Descends to the ground about once a week to defecate and urinate in a hole excavated with the tail. Females produce one young a year. Young are weaned at about six months (Montgomery, 1983). Characteristics: Size medium, about 3-5 kilos. Fur thick, coarse, grayish. Three toes with long claws on each limb. Face appears to be smiling, whitish fur on forehead, dark line through eyes. Throat brownish. Males with patch of short orangish fur with line of spots on back. Short, thick tail. Grooved fur allows growth of algae.