By Katie Scott, Wired UK
A study in which recordings of dolphins made in the 1970s were re-analyzed has revealed that dolphins talk to each other in a manner very similar to human speech, using tissue vibrations.
The study by biologists at Aarhus University in Denmark concentrated on the dolphin’s whistle, which was believed to be produced by the resonance of air in the dolphin’s nasal air cavities. This would have implications for how dolphins communicate at depth — increased air pressure would affect the size of the nasal air cavities and therefore the pitch of the sounds they can make. Instead, the team discovered that the dolphin’s whistle isn’t in fact a whistle at all; but a sound produced by tissue vibrations.
The study centered upon recordings of a 12-year-old male bottlenose dolphin made in 1977 by Professor Sam Ridgway and Dr Don Carder, who were then working for the US Navy Marine Mammal Program. The dolphin, which had been trained for the study, was given a mixture of 80 per cent helium and 20 per cent oxygen (known as heliox) throu...