Ranging behaviors performed by animals are influenced by both biotic and abiotic factors. For herbivorous mammals, seasonality in forage production is considered to be the main driver of movement patterns. Here, we investigated the home range and movement in one of the most abundant herbivores in the Americas, and their relationship with plant phenology in an Amazon igapó - a seasonally-flooded riverine forests with strongly-pulsed leaf-production phenology. Using a combination of telemetry and phenological analysis, the study recorded movement patterns of five brown throated three toed sloths (Bradypus variegatus Schinz, 1825) over a six months period, and related these to seasonal and within-forest differences in food availability via monitoring young leaf production of 570 trees. All monitored animals were shown to be permanently resident within igapó flooded forest, maintaining their home range even during flood periods when most trees lacked leaves. We found that seasonal variation in leaf production had no effect on the extent of displacement of the sloths. Accordingly, for herbivores with low metabolism, variation in young leaves availability may not be the main driver of their ranging behavior. In addition, an arboreal habit and well-developed swimming capacity allow igapó sloths to occupy a niche ecologically inaccessible to other mammals.

Both biotic and abiotic factors are important for maintaining the activity cycles of animals, and may determine the most advantageous periods for eating, moving and sleeping. While the solar day-night cycle is among the most central of abiotic variables, a number of species are active both day and night. Three-toed sloth populations (Bradypus, Linnaeus 1758) across the Neotropics show this pattern, with activity occurring at various points across the 24-hour cycle. In the current study, we used radio tracking techniques to investigate the daily temporal patterning of sloth displacement in Amazonian igapó flooded forest, and compared the results with populations studied in other habitats. We conclude that igapó sloths are cathemeral, and discussed that environmental temperature, nutritional needs and the presence of predators may be the main factors influencing their activity pattern.