Activity Patterns and Rates of Movement of Two-Toed and Three-Toed Sloths (Choloepus hoffmanni and Bradypus infuscatus)

Abstract

Two-toed sloths (Choloepus hoffmanni) and three-toed sloths (Bradypus infuscatus) live in sympatry on Barro Colorado Island, Panama Canal Zone. Activity patterns and rates of movement of six two-toed and 15 three-toed sloths were studied by radio-telemetry in 1970 and 1971. Two-toed sloths were nocturnal and showed a cyclic pattern of activity related to the light-dark cycle. Three-toed sloths were active both during the day and at night, but showed decreased activity before and after sunrise. Individual three-toed sloths did not exhibit cyclic patterns of activity. For both species, the bulk of movement was during bouts of continuous activity lasting 2 or more hours. Three-toed sloths were active for more of each diel than were two-toed sloths. Three-toed sloths were in the same tree on successive dates 40 per cent of the time, and rarely moved more than 38 meters per diel. Two-toed sloths tended not to be in the same tree on successive days, and traveled more than 38 meters per diel more than half the time. Results of our study are interpreted in terms of potential competition between the two species, relationship of activity patterns and movements to feeding strategies, and mechanisms of control of the activity patterns.