______________________________ Marie Trone Randall Balestriero Hervé Glotin Valencia College Université de Toulon Institut Universitaire de France 1800 Denn John Lane av. de l'Université Bt St Michel Paris Kissimee, FL 34744 La Garde, France & Université de Toulon mtrone@valenciacollege.edu randallbalestriero@gmail.com glotin@univ-tln.fr Abstract 1. Introduction Cetacean acoustics research is currently expanding due to recent advances in available technology, in conjunction with decreasing costs of equipment. The capability to record the higher frequencies associated with click trains of many cetaceans of the suborder Odontoceti permits more complete acoustic assessments. However, the copious amount of digitally recorded data produced requires an interdisciplinary approach to develop innovative algorithms and procedures to process, reduce and analyze the resultant complex data sets. Detailed information concerning Odontoceti click acoustics has been derived from studying animals in human care. The ability to finely manipulate variables under controlled conditions has yielded information regarding the timing, frequency and amplitude of clicks. On-axis click signals occur when the receiving animal or hydrophone is positioned directly in front of the signaling dolphin. Off-axis clicks are characterized by lower frequencies and amplitudes when compared to analogous on-axis clicks [R1]. Furthermore, off-axis click trains emitted by multiple animals can produce interference resulting in decreased signal amplitude [R1]. Finally, it has been suggested that the morphology of the cetacean head may cause the signal frequency to decrease as a function of the angle from the beam axis, functioning like a low-pass filter [R2]. However, higher frequency signals have narrower beam patterns than low frequency signals. As a result, high frequency signals are more resistant to signal distortion due to off-axis propagation [R2]. In: proc. of int. symp. Neural Information Scaled for Bioacoustics, sabiod.org/nips4b, joint to NIPS, Nevada, dec. 2013, Ed. Glotin H. et al. 1 6.1 Gabor Scalogram Reveals Formants in High-Frequency Dolphin Clicks