by Penny Sunderland

Created on: July 14, 2009   Last Updated: July 15, 2009

The humpback whale is a large baleen whale that is found in oceans and seas around the world.This is a migratory species, spending summers in northern feeding grounds before heading southwards to warmer waters for the winter breeding season. One of the most intriguing aspects of humpback behaviour is their song. Scientists do not know why these whales sing, but they have collected a range of fascinating facts that may, one day, help explain the purpose of the mysterious song. Here is a selection of some of them.

- Whales have no vocal chords. The humpback whale song is produced by pushing air through the nasal cavities.

- The sounds produced in a humpback whale song can range from high-pitched squeaks to low frequency roars. The sound frequencies can range from 20 to 9,000 Hertz.

-The songs are formed by a complex pattern of sounds. Each pattern can last for between ten and twenty minutes.

-The patterns can then be repeated continuously for hours at a time. Some researchers have observed songs that lasted for more than twenty-four hours.

-While both male and female humpback whales can produce sounds, only the male sings.

-Humpback songs are specific to different regions and populations. For example, all the male humpbacks of the North Atlantic sing the same song, but this is different to the song of the North Pacific humpbacks.

-Singing is most common in the breeding season, but it has also been observed during migration.

-As the breeding season progresses the song gradually changes. New patterns are incorporated and old ones are lost. Long term studies of humpback songs indicate that once a pattern goes out of use it is never repeated.

- It is thought that humpback whales can hear song within a range of approximately sixteen kilometres (ten miles), or possibly more when the sea is quiet. If a human swimmer can hear the song of a humpback, the whale is probably within one to two kilometres (a mile or so). The song can also carry through the air for approximately ninety metres (one hundred yards). This means that if you hear the song from a boat the whale is very close by.

-While sailors have probably heard this song for centuries, it was first recorded by the US Navy in the 1950s, first identified as coming from the humpback whale in the 1960s, and first described in a scientific journal (by Roger Payne and ScottMcVay) in 1971.

Since the song is only produced by the male, and it is most common in the breeding season, it was initially assumed that the male sang in order to attract a female. However, it has since been observed that singing often begins after competition for a mate has ended.

Scientists are now unsure whether or not singing has a role in mating. Research seems to indicate that singing males attract other males, and the song may be a form of social interaction between males. The reason for the interaction is unknown, although there are several theories. Some suggest that the humpback song is a threat to other males. Other researchers interpret the song as a general communication tool, possibly used as a means of keeping migrating, far flung packs of whales in touch with one another.

Research into the nature and function of the humpback song are ongoing. More details and current theories can be found at www.whaletrust.org.

Sources

http://en.wikipedia.org/wiki/Humpback_Whale

http://www.whaletrust.org

A Field Guide to Whales, Porpoises and Seals from Cape Cod to Newfoundland by S. K. Katona, V. Rough and D. T. Richardson

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