Whale song has remained one of natures great mysteries. Can whales actually talk to each other? Can humans understand what whales are saying? To what extent and what distances can whale song reach? These are the significant questions that we want answered, and for now will remain unanswered, however, a handful of the worlds leading cetacean scientists have uncovered an amazing discovery relating to whale song and how whales migrate.
Humpback whales in particular are famous for their underwater communication, and anyone who has swum with the species or used a hydrophone on a whale watching boat can testify to that. The low rumbling groans, or high pitches squeals are synonymous with this intelligent species. A recent study conducted by scientists from the University of St Andrews and the University of Queensland show that humpbacks sing songs shaped by their travels. Male humpbacks who were thought to only sing one song have been found to be able to exchange new songs at select sites along their migration. In essence, the exact route of an individual could, in theory, be understood and reconstructed by listening to their vocalizations.
The team of scientists studied 52 male humpbacks that passed the Kermadec Islands (a sub-tropical island arc in the South Pacific), the results that came back via the ‘Levenshtein Distance Metric’, a technique used to measure musical compositions, categorised the recordings to 3 main songs. The first, most frequent vocalization was heard around the Cook Islands, the second Tonga, and the third Australia. By comparing a multitude of information including similarities and themes, they were able to tell where each whale had been born, confirming these identifications with photographs and genetic markers. There are likely other migratory junctions at which new phrases and themes may be exchanged, but the Kermadec’s are the first such place that’s been found. This was a momentous occasion for tracking and conservation, and while we can never truly understand what the whales are communicating, it is a fascinating insight into the lives of the leviathan.
Other species of whale have been subject to extensive research, fin whales in particular emit sounds so low they are almost undetectable by humans. In a study last year that analysed more than 1 million individual recordings of whale calls, shifts in sound waves and whale song were found across species, and interestingly even among species and populations that don’t interact with one another. What has triggered the change is unknown, however human’s increase in marine traffic and ocean industry may be the offender. The noise caused by vessels could be so great that whales have had to change their song.
Another, more positive explanation for the change in whale song could be that cetacean conservation efforts have been successful. For populations of whales that were decimated by the whaling fleets of the 20th century, but have now rebounded, scientists have speculated that the whale’s anatomy determines that the louder it gets, the higher the pitch of its calls. As populations have grown, then, the whales may have decreased their volume because they are more likely to be communicating over short distances.