Distribution of two sympatric species of sloths (Choloepus didactylus and Bradypus tridactylus) along the Sinnamary River, French Guiana

During the filling of the Petit Saut dam in French Guiana, a wildlife rescu e operation was conducted for 17 months. Over 900 sloths (Bradypus tridacty lus and Choloepus didactylus) were captured along the Sinnamary River in a primary rain forest that was largely undisturbed at the outset Raw densitie s of 1.7 B. tridactylus/km(2) and 0.9 C. didactylus/km(2) were estimated. T he distribution of captures was relatively continuous for both species alon g the rivers; variations mon likely reflected biases due to capture methods . The highest densities of captures were located mainly in marshy areas. Du ring the first months, due to different probabilities of sighting the two s pecies, B, tridactylus captures predominated; however, as defoliation advan ced, captures of C. didactylus reached the same level. In both species, ove r 73 percent of individuals captured were solitary and another 23-24 percen t were females carrying young, accounting for 96 percent of emancipated ind ividuals.