Internally coupled ears in living mammals

Area of Science:

• Comparative anatomy
• Auditory neuroscience
• Mammalian evolution

Background:

• Mammalian auditory systems typically feature acoustically isolated middle ears.
• Neural computation is usually required for sound localization cues.
• Some mammals exhibit intercommunicating middle ear cavities, enabling pressure-difference reception.

Purpose of the Study:

• To investigate the potential benefits of intercommunicating middle ear cavities for sound localization in low frequencies.
• To explore the unique middle ear morphology of the platypus (Ornithorhynchus) and its implications.
• To examine the acoustic coupling in talpids and golden moles and its relevance to auditory perception.

Main Methods:

• Comparative anatomical analysis of middle ear structures.
• Review of existing experimental data on acoustic coupling in talpids.
• Hypothesizing auditory capabilities based on middle ear morphology.

Main Results:

• Platypus middle ears are uniquely open to the pharynx, resembling non-mammalian tetrapods.
• Talpid and golden mole middle ears can be connected via basicranial air passages, allowing acoustic coupling.
• Experimental studies confirm acoustic coupling in Talpa middle ears.

Conclusions:

• Intercommunicating middle ears may offer advantages for low-frequency sound localization.
• Mammals with internally coupled ears, like platypus and moles, could benefit from enhanced sound localization.
• Further experimental research is needed to confirm the functional auditory benefits in these species.