The evocative sound of whale song has long fascinated whale watchers and others alike. In the 1960s, recordings were first made of the song of humpback whales. These captured public imagination – musicians like Judy Collins used whale song on recordings, and whale song was included in the Golden Record that was sent to the far reaches of space aboard the Voyager spacecraft. Such public interest contributed to the banning of whale hunting and use of whale products in the USA in 1972.
How do Whales Sing?
Toothed whales produce a series of clicking noises for echolocation (a form of sonar used in hunting and navigating). It is the sounds produced by some baleen whales, for communication purposes, that are termed whale song. Amongst the fifteen or so species of baleen whales, only a few types are known to sing, notably the minke whale, the blue whale and the humpback whale.
The exact mechanism for producing song is not entirely known. In their voice boxes are several folds, which probably vibrate, acting as vocal cords and producing sound. While human vocal cords work by varying outward airflow to modulate sound, the vocal cords of whales are linked with sacs that line the throat. Underwater, it is speculated, air can be moved from these sacs to the lungs, so that the whale can produce sound, but keep air within its body until it next it breaches the water’s surface to breathe.
Why do Whales Sing?
Because other senses are less effective in water, marine mammals are more dependent on sound for communication than land animals. Water is denser than air, so sound travels through it more effectively.
The exact function of singing seems to vary between types of baleen. Amongst humpback whales, only the males sing, and only in mating season. This lends to the theory that their song is part of mating behaviour, to communicate fitness and youth to the female. Some other baleen whales use a different song pattern, not limited to mating times, which could be related to feeding or even to expressing emotion, for example being separated from the pod, or mourning the death of a whale in the pod.
Humpback Whales Change their Tune
Research has shown that humpback whales in the same region sing the same tune in chorus, even when they are many miles apart. Whales in another region, however, will have a different song, sung in unison. The sounds making the song are deep and of very low frequency. They continue singing for many days, repeating the individual song which may be from a few minutes to half an hour long.
A 13-year study of the songs of humpback whales was published, in November 2018, by researchers at the University of Queensland and the University of St. Andrews in Australia.
This study, of 95 whales off the Australian coast, has found proof that groups of whales change their song every few years. Over the years, a group’s song is added to by some whales, and the changes are adopted and learned by the rest of the group. It is suggested that, when the song becomes too complex to manage, it is abandoned by the group and a new, simpler tune started.
Whale groups, unlike some human ones, do not, it appears, let musical differences split them up!