Terrestriality of Wild Sapajus cay (Illiger, 1815) as Revealed by Camera Traps.

Although primarily arboreal, the capuchin monkey (Sapajus cay) descends to the ground for several reasons. We used terrestrial records obtained by camera-trapping surveys to investigate seasonality in the terrestriality of capuchin monkeys, reasons to descend to the ground, and periods of the day when terrestriality was more pronounced. We carried out the study in the Urucum Massif, Brazilian Pantanal. We obtained data from 2 camera-trapping surveys carried out in the dry and rainy seasons. Terrestrial behaviours were categorized, and terrestrial activity patterns were described using a kernel density approach. We observed a seasonal effect on the frequency of terrestrial behaviours of capuchin monkeys, who used the ground more during the dry season. We identified 6 different types of terrestrial behaviour, but travelling (33.3%), foraging (23.3%), and drinking water (23.3%) were the most frequently observed. All records occurred during the day, with 2 peaks in terrestrial activity. Seasonal terrestriality was mainly linked to ecological needs during periods of scarce food and water.