Vocal Exchanges between Dolphins: Bottlenose dolphins "talk" to each other with whistles, clicks, and a variety of other noises

Observations of the vocal exchanges of bottlenose dolphins under various conditions are presented. Experimental conditions under which isolated emissions from each animal of a pair are separately recorded and in which the distance between the rostrum and the hydrophone is controlled are described. The exchanges consist of vocal alternations (A, then B, then A, and so on), "duets" (A plus B simultaneously), and long "solos" or "monologues." The emissions exchanged are: (i) whistles alone; (ii) slow click trains alone; (iii) simultaneous whistles and clicks from either or both animals; and (iv) squawks, quacks, blats, and so on, alone or simultaneously with whistles. Any or all of these sounds may occur in a given period. The significant carriers of meaning are to be determined. (Suggestions include various functions of relative amplitudes, absolute and relative frequency, frequency modulations, phaseshift variations, and durations of whistle emissions.) Average and peak amplitudes (at the rostrum) of each class of sound cover at least a 100-decibel range (controlled by the dolphin).