Editing Pakicetidae (section)

==Hearing==
Pakicetid ears had an [[external auditory meatus]] and ear ossicles (i.e. [[incus]], [[malleus]], [[tympanic ring]], etcetera) similar to those in living land mammals and most likely used normal land mammal hearing in air. In the pakicetid mandible, the [[mandibular foramen]] is small and comparable in size to those of extant land mammals and the acoustic mandibular fat pad characteristic of later whales was obviously not present. The lateral wall of the mandible is also relatively thick in pakicetids, further preventing sound transmission through the jaw. The [[tympanic bulla]] in pakicetid ears is similar to those in all cetaceans, with a relatively thin lateral wall and thickened medial part known as the [[involucrum]]. However, in contrast to later cetaceans, the [[tympanic bone]] makes contact with the [[periotic bone]] which is firmly attached to the skull leaving no space for isolating air sinuses, effectively preventing directional hearing in water. Pakicetids most likely used bone conduction for hearing in water.<ref>{{Harvnb|Nummela|Thewissen|Bajpai|Hussain|2007|loc=Pakicetids, pp. 722–3}}</ref>