Sound Emitted by Dolphins

Abstract

During a cruise in the Mediterranean last year on board the Swedish research ship the Skagerak, I happened to notice that the dolphins (Delphinus delphis) uttered sounds that were quite audible on board the ship, though the dolphins were swimming one or two metres below the surface. The sounds may be described as short, rapidly repeated squeaks rather like those produced by fighting or playing mice. As I had many opportunities of listening to the sounds, sometimes with the ship at rest in calm weather, and had several other persons verify the observation, there can be no doubt as to the ability of the dolphins to produce audible sounds.