| Odontocete cetaceans have some of the most sensitive hearing in the animal kingdom. Despite over a half-century of research on these animals, there are still many aspects of their functional anatomy and physiology that have not been described or even explored. Directional hearing allows an individual to locate an object in space and is important in foraging, predator avoidance and social cohesion. Despite notable publications on the directional hearing in bottlenose dolphins, there is still an incomplete picture as to the three dimensional hearing capabilities of these animals. This study uses auditory evoked potential (AEP) techniques to explore the directional hearing capabilities of an Atlantic bottlenose dolphin (Tursiops truncatus). Audiograms obtained for different design regimes were compared. Then, using an underwater in hoop with biteplate setup was used to obtain the directional hearing thresholds in multiple angles in the horizontal plane and depths. In addition to the threshold values, the first head-related transfer function (HRTF) on any marine mammal species was collected. These studies promise to shed greater light on the plasticity of directional hearing and localization capabilities. |
