Mechanisms of Sound Production in Delphinid Cetaceans: A Review and some Anatomical Considerations

The past literature describing the possible sites of the sound-producingmechanisms in delphinid cetaceans is reviewed. The morphologyof the nasal sac system of delphinids which has been implicatedin the production of sounds, by most investigations, is discussedwith special emphasis placed on the physical characteristicsof these sounds. New data on the histological structure of theepithelia throughout the nasal region of a delphinid are presentedwith some suggestions as to its function. The presence and structureof glandular tissues are described along with a discussion oftheir potential role in the production of sound. It is concludedthat the theories implicating the nasal sac systems of odontocetecetaceans in the production of sound are additionally supportedby certain anatomical specializations adjacent to the tissuesof this system.