Intensity daffy from head shadow may provide some direction cues. However, intensity is generally most useful at higher frequencies. So sound localization is suspected to be poor. Middle ear cavity large and line with thick vascularized fibrous sheet. Bimorphic construction and complex shape of tympanic membrane make estimates of active area difficult, but expected to have a complex frequency dependent response pattern.
Cochlear windows are large but conventionally structured.
Ossicular chain is massive, nearly straight and loosely joined. Stapes is remarkable in being columnar. No conventional mammalian, stirrup like crura. This implies it is nearly one third of manatee facial. Malleus is thick ovoid with ventrolateral manubrial flange Large tensor tympani muscle inserts on a small lat malleal pedicle.