Audition presents an interesting problem in reptiles. Snakes and some lizards have no external ear, although the middle and inner ears are present. In species with a distinct external auditory meatus, there is little doubt about the existence of a sense of hearing, although it is generally thought that only sounds of low frequency are detected. In species lacking an external ear, seismic sounds are probably conducted by the appendicular and cranial skeletons to the inner ear. It has been suggested, however, that the lungs might respond to airborne sounds and transmit them to the inner ear via the pharynx and eustachian tube. Although no reptiles are known for having beautiful voices, many generate sounds. For example, male alligators bellow, and this sound undoubtedly serves social functions. Many snakes hiss, some growl, and a fair number issue sounds with their tails either with a rattle or by lashing the tail against the substrate. Such sounds are generally aimed at predators or other heterospecific intruders, and herpetologists have believed that the issuing organism was deaf to its own sound, unless the sound had a seismic component. Perhaps this view can be altered if the concept of pneumatic reception of airborne sound is corroborated.

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