Abstract # 147:

Scheduled for Saturday, June 21, 2008 11:15 AM-11:25 AM: Session 16 (Meeting Room 1GHI) Oral Presentation

Hoot Calling in Owl Monkeys (Aotus azarai) of Argentina: Sex Differences and Function

C. D. Depeine1, M. Rotundo1, C. P. Juarez2 and E. Fernandez-Duque3
1Fundación ECO, Formosa, Argentina, 2Centro de Ecología Aplicada del Litoral, Conicet, Argentina, 3Department of Anthropology, University of Pennsylvania, Pennsylvania, USA
     Owl monkeys are socially monogamous primates that live in groups of 2-5 individuals. The vocal repertoire of owl monkeys includes a loud “hoot” call that can be heard over long distances. To evaluate their possible function, we compared hoot calls given by free-ranging males and females within ongoing studies in three different contexts.  First, we compared the hoots given by marked individuals during the removal of their partner for a physical examination (4 males, 3 females).  The second and third contexts included the playback of hoots recorded from a sub-adult male to radio-collared solitary females (n=3), and seven playback sessions to unidentified individuals (n=7) spread over a two month period (October-November) ranging over 150 ha of forest.  Partner removal elicited two different types of hoots in males and females.  Males gave deep, rough, “dog-like bark” hoots, whereas females produced higher-pitched “tonal” hoots.  The playback of the sub-adult hoot call elicited only tonal hoots from the three solitary females.  Similarly, the unidentified individuals ranging in the study area only responded with tonal hoots to the playbacks. Our preliminary findings provide evidence that there is sexual dimorphism in the types of hoots given by male and female owl monkeys.  Given this potential sex difference, it seems reasonable to propose that the hoot calls may play an important role in mate attraction.