Pilot whale acoustics

Globicephala melas

The Pilot whale acoustic production includes clicks, whistles and pulsed sounds, along with numerous “social” vocalizations.

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The clicks are wide frequency band, with maximum energy between 8-9 kHz, used for echolocation. Whistles are modulated with a strong harmonic component.

The opportunity to make direct and continuous observations over a pod of pilot whales, has uncovered important aspects of the species acoustic repertoire. In particular, the long-term stability of the 'signature whistle', a stereotyped vocalization characterizing each individual.

Spectrogram of a sequence from Santiago, an adult male of about 6 m

 

   

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The limited number of individuals observed (max 6) has allowed us to isolate the sources of noise and give the pilot whale individual whistles, to show that these cetaceans mainly produce their signature whistle (80%).

These vocalizations are proved to be stable over time (Archive 1995-2003) and their "boundary" time versus frequency is highly stereotyped.

This outline may vary in duration, number of repetitions, some parts may be omitted, however, is clearly recognizable.  Males calls were predominant (90%).

Spectrogram of a sequence from Cagliostro, pilot of the pack of about 7 m

 

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Finally, it was possible to document the development of a signature whistle in a sub-adult male, age 1-2 years until the age of 8-9 years. Pan, sub adult male, developed his whistle over the years: to a simple whistle, Pan adds an introduction and a terminal vocalization.

Spectrogram of the signature whistle from Pan, sub-adult male of about 4 m