Our lives are enriched by music and conversation and altered by the sounds of danger.

Many mammalian species have a particularly acute sense of hearing. Hearing depends on the remarkable properties of hair cell receptors in the cochlea that mediate transduction of sound into action potentials that are then sent to the brain. Fortunately, the auditory system is not usually a site of pathological lesions in veterinary medicine, except for occasional congenital defects and exposure to ototoxic drugs. Nevertheless, hearing is sufficiently important to warrant a brief discussion of its physiology.