The Humpback Whale songs repeat in cycles between approximately ten and thirty minutes. Individual Whales have been documented as singing continuously for up to twenty four hours. The Whales each sing the same cycle, although they each commence the song cycle at different intervals. So a low frequency pulse may be responded to by a high frequency pulse giving them Sonar (Sound Navigation and Ranging) feedback on each other’s position. We base our cycle timing of the whale song on the crescendo to the high frequency pulses. Note the subtle but definite descent in frequency of each of the passages syncopated by low frequency staccato pulses. Viewed with a spectrogram the low frequency pulses can be seen to be very precise chords of frequencies. The song is clearly audible through the hull of the research vessel although the sound pressure level of the song is reduced significantly once it passes into the air. Because water is denser than air it is a much better conduit for sound. If a singer is close you can hear the song while standing on the deck. If you enter the water the song is then felt at its full sound pressure level which is the equivalent of a jet engine or loud rock concert. Doctors Roger and Katy Payne were the first scientists to recognize that the unique sounds made by Humpback Whales were in fact conscious, complex evolving songs. They found that the songs varied markedly from year to year and that “new variations are learned traits which evolve”. Three researchers in Hawaii, two computer engineers and a marine biologist, have created a computer application to assess the entropy of whale sounds and have compared them to a range of human languages. They have concluded that Humpback sounds are equivalent to human languages.
Posted on: Thu, 22 Aug 2013 06:29:39 +0000
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