Abstract # 144:

Scheduled for Saturday, June 21, 2008 10:30 AM-10:40 AM: Session 16 (Meeting Room 1GHI) Oral Presentation

Acoustic Characteristics of the Vocalizations of Mantled Howler Monkeys (Alouatta palliata) in the Fragmented Low-Land Forests of Honduras

C. A. Bustos1, L. D. Corkum1, K. Y. Slater2 and D. J. Mennill1
1Department of Biological Sciences, University of Windsor, 401 Sunset Avenue, Windsor, Ontario N9B 3P4, Canada, 2Research Department, Operation Wallacea, UK
     A central question in the study of primate behaviour concerns the extent to which primate vocalizations are acoustically adapted for specific communication functions. No current studies have analyzed the acoustic characteristics of Mantled Howler Monkey vocalizations living in fragmented forest populations. The goal of this study is to provide an in-depth description of the fine structure of the vocalizations of Mantled Howler Monkeys (A. palliata). Close-range (<20 m) recordings were collected from seven different mantled howler monkey troops in the low-land forests of Cofradia, Honduras. We analyzed the 10 best representations for each vocalization for each group. Barking and howling were the most frequently recorded vocalizations, although we identified 10 types of vocalizations in total. The loud, namesake, howl vocalization had the highest frequency characteristics (average frequency of maximum amplitude 423 Hz) which may reflect an adaptation to maximize transmission of this territorial signal. Soft barks, in contrast, showed the lowest frequency characteristics (average frequency of maximum amplitude 286 Hz) which suggests that they may play an intra-group communication function. Examination of form and function in vocal communication will reveal links between structure of vocalizations and receiver responses. Such links will add novel insight on the adaptive significance of the various calls identified in mantled howler monkey vocal repertoire.