THE PRODUCTION OF SOUNDS 



221 



Figure 115. Two Bottlenose Dolphins approaching the hydrophone in the Marineland 

 Aquarium, Florida. {Photograph: F. S. Essapian, Miami.) 



investigators aboard the French research ship Calypso have corroborated 

 this statement. How high-pitched these notes really are was fully appreci- 

 ated by F. C. Fraser \vho failed to hear them altogether, while his colleagues 

 just could. The real intensity of the sound became apparent when the 

 shrill and piercing cries of newly caught and frightened Bottlenose 

 Dolphins penetrated through the thick glass plates of the Marineland 

 Aquarium in Florida and could be heard in the passages. A loud squeak 

 was also heard by the well-known underwater photographer Hans Hass, 

 when, off the Azores, he filmed the mouth of a harpooned and dying 

 Sperm Whale. The noise was very clear and strong and appeared to come 

 from the throat, and - according to Hass - was certainly not accompanied 

 by movements of the lower jaw. Worthington and Schevill recorded 

 hammering and other noises made by whales off the coast of North Caro- 

 lina, and the young Sperm Whale which lost its life while investigating the 

 Calypso's screw was heard to emit a shrill whistle. 



All these superficial observations tell us little about the real nature and 

 significance of the noises, which have only been studied since 1948, when 



