a singing humpback whale

One of the greatest mysteries of the animal kingdom is the whale song. The male humpback whales do the singing in the breeding grounds. This has lead researchers to believe that it is either an attempt to attract females or to ward off other males.

Singers are usually lone animals, staying in one spot. They sing about 50-60 feet below the surface, for about 20-40 minutes, with their heads pointed downwards and their tails pointed upwards. The song has a very complex structure, similar to a classical music piece. It can be broken down into units, phrases and themes, which make up the entire song.

Today, scientists know more than ever about the song of the humpback. They know, for instance, that while both male and female humpbacks can produce sounds, only the males appear to produce organized songs with distinct themes and melodies, almost always on breeding grounds. As nature’s humpback whales shows, the males often sing while suspended deep below the surface, their long front flippers jutting rigidly from their sides. The songs can last up to 20 minutes, and can be heard more than 20 miles away. The male may repeat the same song dozens of times over several hours, and whales in the same geographic area sing in very similar “dialects.” Song patterns can change gradually over time, so that new songs emerge every few years.

Researchers still aren’t sure exactly how the whales produce the sounds. Whales don’t have vocal cords, so they probably sing by circulating air through the tubes and chambers of their respiratory system. But no air escapes during the concerts, and their mouths don’t move.

Scientists are also unsure about what the songs mean. Originally, observers believed they were a mating call, used to advertise the male’s availability to passing females. This idea was reinforced when divers observed other whales approaching the singers.

More recently, however, some researchers have come to believe that the singing humpbacks are actually issuing threats, not singing love songs. In part, that idea arose because scientists discovered that many of the whales approaching singers were other males, and the meeting would often end in a tussle.

Another recent theory is that the singing whales are simply finding out who is in the neighbourhood, using the songs as a form of sonar for tracking nearby whales. But many scientists are skeptical of the idea, in part because the whales only seem to sing on breeding grounds.

Many animals, including humans, use pitch or frequency to communicate information, and this may be an important element in the whale’s message. Since all humpback songs include a combination of frequencies, the humpback could be using different frequencies to send different messages to different individuals. Thus, if all singing whales are in fact males, the low frequencies could be a threat to other males, the high frequencies an inducement to females to come closer, and the changing frequencies a means of calling attention to themselves.

One phenomenon among humpback whales is that their songs change to some extent each year; this year’s song is always slightly different from last year’s. All the changes take place during the singing season, not between seasons, and all the whales change their song together as the season progresses. The changes are not drastic and may involve only a slight change in two or three sounds. The basic frequency patterns remain the same; for example, moans may change from long to short or wavery, but they are still moans.

The reason for these changes is not understood. It may be that a new song each year is more stimulating for the females, or that one dominant male decides the song for the year, but for whatever reason, most humpbacks in a breeding area sing the song for the year, including the seasonal changes. Since a single song lasts 10 to 30 minutes, performing it is a feat of memory particularly remarkable because of this constant song-evolution (Payne, 1991). Payne (1991) has documented the changes that have taken place in two populations of whales over the course of 5 and 19 years, and has shown that the individual whales always keep up with the current version of their population’s song. As you can see, the song of the humpback whale is extremely fascinating and complex. The sounds are not simply for entertainment-they serve as a set of guidelines and communication for individuals in a group of whales. Without these songs, males would find it difficult to attract females, groups would often be split up during migration, and coordinating feeding behavior would probably be non-existent. It is often difficult to express the wonder of these sounds in words. Payne (1996) describes it well:

“As you sit in your boat, lightly borne on the night sea, watching the weather and the stars and the sails, it all seems so simple, regular, ordinary, and you have no thought of how far beneath you the abyss extends. But then you put on headphones, and after a while a whale starts to sing, and the echoes from the abyss come tumbling and roaring back, and suddenly you are aware of the vastness of the mystery that underlies your boat.”