Singing Whales

Humpback whales (Megaptera novaeangliae) are the most musical of the mysticete whales. The songs of the humpback were first detected by military arrays in the 60’s. And when scientists dropped their hydrophones into the waters of the breeding grounds, they were instantly intrigued by the deep, haunting sounds of the whales. And indeed, humpbacks truly do sing songs.

The sounds they make are organized into themes, repeated consecutive phrases of music. Individual phrases of the song are usually only last a few seconds and under 1.5 kHz in frequency. The sounds include long groans, low moans, roaring sounds, trills, and chirps. Each song lasts anywhere from 8-16 minutes and the whale may sing for hours on end, repeated the song over and over again. All the whales that share a breeding area sing the same song. That means that the whales in the North Pacific sing a different song than the whales in the North Atlantic. The songs also evolve over time. Individual phrases are dropped, new ones inserted or the sequence of themes is altered slightly. Over time (many years), an entirely new song will come about. How do the changes occur? Scientists do not understand the process completely but believe that it may be forgetfulness or innovation. Then, other whales actively learn from each other, and the changes are passed on through the group (kind like the game "Telephone").

Why do they sing?

Underwater observations of humpbacks have determined that it is only the males that sing. Likewise, the songs are only heard on the breeding grounds. This leads biologists to think the songs are a kind of breeding behaviour. Perhaps the songs are a way to attract females or to mark their territory. It is thought that the way the male sing indicates to a female that he will be a good mate. Although all the males are singing the same song, they are not synchronized. There is random overlap with small variations. Perhaps the whale with the most novel song is a dominant whale. What is most fascinating about the songs of the humpback is that we still do not know how they do it. Whales do not have vocal cords and the long, deep and musical sounds of the humpbacks leave whale biologists mystified. It is most likely that the sounds are produced somewhere in the nasal passages (similar to echolocation sound production), but the process is not fully understood. So, as research continues, the song of the humpback continues to haunt us.

Source: http://oceanlink.island.net/