Variation in sound production in relation to behavior of bottlenose dolphins (Tursiopsaduncus)

Dolphins are social animals that inhabit an opaque environment where visual cues are often limited, thus acoustic signals play an important role in inter‐ and intragroup communication. Phonations may be used to signal conspecifics, in navigation, or in the detection of prey, and may vary with behavior, environmental conditions, or geographic location. Variation in the acoustic and surface behavior of two geographically separated and genetically differentiated populations of bottlenose dolphins in Southeastern Australia were investigated over a 3‐year period. Two hypotheses were tested: (1) vocal repertoire varies with behavior; and (2) variation in vocal repertoire may have arisen due to geographic isolation. Overall rate of sound production by the dolphins was similar in each field site but varied significantly with behavioral activity. Call rates were highest with behavior that involved increased arousal, such as socializing and foraging. Whistle rates and the duration of echolocation click bouts were s...