A case study of biological pulsed sound : the blue whale’s southeast Pacific song unit, models and properties

Pulsed sounds are interesting as an example of complex biological sound. We propose a classification into two groups for the pulsed sounds: tonal or non-tonal. Two mathematical models allow to see the properties of the sound in both cases. This classification is useful for developing new measurements that can be more accurate and can distinguish between two possibilities of sound production. We apply our method to blue whale vocalization and find that the pulse rate corresponds to the fundamental frequency (not expressed in the spectrum) of the song. Thus, we reinforce the hypothesis that the sound is produced by only one organ and then filtered by the body of the giant.