THE VOCAL AND BEHAVIORAL REACTIONS OF THE WHITE WHALE, OR BELUGA, (DELPHINAPTERUS LEUCAS) TO UNDERWATER PLAYBACK OF NATURAL AND SYNTHETIC BELUGA SOUNDS

Abstract

Underwater playback of natural and synthetic sounds was shown to be an effective tool for investigation of communication in Delphinapterus leucas, the beluga. Natural sounds were used to determine the significance of the sounds to the animals, and synthetic sounds to determine some of the parameters of the sounds that had an effect on their significance. The general, overall response of captive animals was an increase of interest in the sound source during the playback, with decreasing interest in the three minutes following playback. The general response of free-swimming belugas was a decrease of vocal emissions. A strong, stereotyped, vocal response was elicited from one captive animal by the Harmonic Long, Loud Whistle; and synthetic sounds, based on this natural sound, showed that both duration and frequency affected the significance of this sound. It is suggested that the Jaw Clap or Bang should be regarded as a general 'alerting' or 'attention' call, permiting it to serve as either an alarm signal or a threat. The Squeals of the free-swimming herd may have been associated with the calves, being produced either by the calves themselves or by accompanying adults. Both syntax (the combination of individual sounds into sound-series) and context were important in the conveyance of information by the playbacks. 'Scouting behavior' occurred during the playback of some sounds. A functional classification of animal sounds is proposed. Suggestions are advanced for further work with the vocal behavior of the beluga.