My little nephew used to call him the Prince of whales
The function of whale song, even the better-studied song of the humpback whale, has long baffled marine scientists. Songs of the blue whale, the planets largest living creature, can be divided into at least 10 types worldwide, each type retaining the same units and similar phrasing over decades, unlike humpback whale song which changes substantially from year to year. That is until recently with a worldwide occurrence of a nearly linear downward shift in the tonal frequencies of blue whale song.
“We don’t have the answer. We just have a lot of recordings,” Whale Acoustics President Mark McDonald explained to Wired. The company specializes in analyzing the cetaceans with sonic monitoring networks and ships. Their recordings are grist for experts hoping to unravel this mystery. “It’s a fascinating finding. It’s even more remarkable, given that the songs themselves differ in different oceans. There seem to be these distinct populations, yet they’re all showing this common shift,” Cascadia Research Collective blue-whale expert John Calombokidis adds.
Historical acoustic recordings dating back as faras the 1960s were examined, measuring the tonal frequencies of 1000s of blue whale songs. Within a given year, individuals match the song frequency (related to ‘pitch’ in musical nomenclature) to within less than 3%.
The best documented song type, that observed offshore of California, USA, now is sung at a frequency 31% lower than it was in the 1960s. Data available for 7 of the world’s 10 known song types show they are all shifting downward in frequency, though at different rates.