Abstract
Tree cavities used as sleeping sites are a limited resource for arboreal mammals. The shared use of arboreal cavities as sleeping sites between Neotropical mammals is rarely observed and has been little studied. We documented an event of sleeping site sharing between two medium-sized mammals, the Caribbean night monkey (Aotus griseimembra) and the Quichua porcupine (Coendou quichua), recorded in the humid lowland forests of the inter-Andean basin of the Magdalena River in the eastern part of the Department of Caldas, Colombia. The sleeping site sharing occurred in an avocado tree (Persea americana) over a period of three days and included an agonistic encounter between the two species. The group of Caribbean night monkeys was always near one of the two cavity entrances, entering near sunrise and leaving near sunset, while the two Quichua porcupines were inside the cavity, in different positions, and remained in the sleeping site even after dusk and before dawn. This study provides new information on the interaction between night monkeys and porcupines, and on the sharing of tree cavities as sleeping sites.