Songs of the Great Whales
Saturday, October 24th, 2020 | Blog
Baleen whales produce complex sounds consisting of distinct sequences of tones ranging from high-pitched squeals to frequencies too low for human ears to hear. These sounds vary considerably in character. Noises that the human brain interprets as grunts, moans, roars, clangs and sighs can all be heard, in sequences that may last ten minutes or longer. The whales may use these sounds to identify themselves to one another, assert mating claims, make long-distance contact and warn of threats; they may also, as stated above, use sound as an aid to navigation.
Blue whales have loud, deep voices that carry great distances. A number of distinct songs have been identified; these are associated with particular subspecies or populations. The distinctive four-note song of a blue whale subspecies in Sri Lankan waters has been repeatedly heard and recorded. The song is always the same, with three short pulsed notes followed by an extended note of frequency about 110Hz, lasting about 28 sec. Fin whales make low-frequency sounds inaudible to humans, which other members of their species can detect at distances of more than 600km.
Bryde’s whales sometimes generate short (0.4sec), powerful low-frequency vocalizations that sound to human ears like a truncated moan, while minke whales create a number of sounds, including clicks, grunts and clangs, ranging in frequency from 60Hz to 12kHz.
Of all the sounds of the great whales, the most interesting and complex are the ‘songs’ of humpback whales. Unlike other whales, humpbacks produce long, intricate sequences of tones that the marine biologist Philip Clapham has called ‘probably the most complex in the animal kingdom’. These songs are produced by male humpbacks during the mating season and most likely serve the same purpose as birdsong in mate selection – that is, they may be the means by which male humpbacks ‘flirt, compete for mates or establish territorial claims. The songs of members of different humpback populations are similar to one another and differ from the songs of other populations.
A humpback whale song begins with a single tone or note, growing in intensity and lasting several seconds. The note may modulate in amplitude (volume) or frequency (pitch). A cluster of such notes is called a phrase; phrases are repeated several times to form a theme. A typical theme lasts from ten to thirty minutes. Themes are repeated continuously for hours at a time to build a song.
Reflected off the seafloor, the song of a humpback whale can be heard underwater at least 160km away – possibly much farther.
Interestingly, baleen whale larynxes lack vocal cords, so the means by which they produce these impressive sounds is unknown to science.
By Howard Martenstyn