Sound localization in the median plane

In this project we are focusing on sound localization in the median plane. While all terrestrial mammals need their pinnae to localize sound in this plane, harbour seals and other phocid seals lack pinnae. This raises the question if harbour seals are anyway able to accurately determine the location of a sound source if sounds come from above or from below as well as sounds coming from the rear or from in front of the animal. And if they can do so we want to understand the mechanism that allows them to localize sounds in this plane.

In the video seal Sam holds on a vertical bite-target this way laying in a stationary position on its right body side. A sound is either generated right above its head (the example of the video) or below its head. After the sound has been played to the seal it moves its head to one of the response targets to signal the experimenter from which direction it has perceived the sound.