Internally Coupled Ears (ICE): the cool part of sound localization

Internally coupled ears, for short ICE, provide a powerful means of enhancing (in a direction-dependent fashion) the input difference between left and right ear due to an external sound source. ICE occurs in many animal groups, such as frogs, lizards, birds, and crocodilia. It will be shown that two factors play a key role. First, the physical geometry of the air-filled cavity connecting the two ear drums. Second, the fundamental frequency and hence the elastic properties of the tympani connecting the outside auditory world with the air-filled interior connection. Treated together, these factors allow physical and hence mechanistic insight into how ICE works.