Morell, M., Degollada, E., van der Schaar, M., Alonso, J.M., André, M. Comparison of Odontocete Ears through Computerised Tomography 19th Conference of the European Cetacean Society, La Rochelle, France, 2005 Résumé: While there is an increasing concern about the impact of noise on cetaceans very little is known on the species related hearing capabilities and the use of sounds in their environment. Although some data are available for some species (e.g. audiograms and full bandwidth signals), no basic morphological comparison of the tympanic-periotic bullae has been conducted to establish a standardised anatomical database. Here, we present a method of analysis based on the comparison of nine odontocete species hearing systems through computerised tomography which shows that standard size and volume measurements may help to ascertain the relationship between specific morphological parameters (air spaces and intra-cochlear volume) and the species known sound characteristics, i.e. the frequency bandwidth. Projet: Noise pollution effects on cetaceans