Understanding Behavior And Nest Box Usage In Three Species Of Owl Monkeys

The use of tree holes and nest building behavior is uncommon among most primate species. In research facilities that house species requiring nesting sites, such as those that use tree holes in the wild, providing nest boxes is crucial to their psychological well-being. The goal of this study was to determine nest box preferences among three species of captive owl monkeys: Azara's owl monkey (Aotus azarai), Nancy Ma's owl monkey (A. nancymaae) and Spix's owl monkey (A. vociferans). The subjects were housed at The University of Texas M.D. Anderson: Keeling Center for Comparative Medicine and Research Core and Animal Resources, Bastrop, TX. Five family groups from each species, ranging from 2-5 individuals, were observed for location and behavior from 21 June 2012 to 23 August 2012. The facility provided four different types of nest boxes: [1] a mesh box, [2] a covered box of the same size, [3] a horizontal bucket, and [4] an opaque white box. As a nocturnal species, the owl monkeys are maintained on a partial reverse light cycle and the rooms are equipped with louvers, allowing the owl monkeys to experience a "dusk" period in the lighting. While A. azarai spend more of their sleeping time in dense foliage in the wild compared to A. nancymaae and A. vociferans, in the current study, although they were provided with nest boxes meant to mimic this type of nesting site, A. azarai did not spend more time (13.6+19.1%) in the nest boxes compared to the other two species (A. vociferans 18.4+18.8% and A. nancymaae 8.1+18.0%). All three species employed a variety of sleeping sites including the nest boxes as well as other cage substrates such as the floor and perches. One factor contributing to sleep site selection was the size of the group and the size of the nest box. A. azarai are generally considered more cathemeral than the other species. In the current study, the activity level of A. azarai was much higher (77.3 + 15% resting) compared to A. nancymaae (93.3 + 11) or A. vociferans (97.9+3) during the dusk period. Dusk is usually a peak time for all owl monkey species to forage and to travel; however, in captivity the pattern may be different.