Whales

Whale Songs

Some whale species produce a pattern of regular and predictable whale sounds, the most notable being the Humpback Whale. It has been compared with human music, with these creatures being the 'composers'. On the other hand, most toothed whales do not produce whale song, but instead produce rapid bursts of high-frequency clicks and whistles. Single clicks are known to be used in echolocation; however, a collection of clicks together is for communication. Male Humpback Whales perform these vocalisations only during the mating season, which suggests that the purpose of their songs is for selection of a mate. It is unknown whether it also is their means of defining territory or even flirting between males to females.

Whales occupying the same geographical location tend to sing similar whale songs, only varying them slightly. However, whales from areas that do not overlap sing different songs. A study over a period of 19 years found that the same song combinations never occurred, therefore suggesting that whales never reuse old song patterns. Whales in one area sing the same song at any point in time, a song which constantly and slowly changes over time. Over any given period, one song will start with increasing frequency but may slowly flatten to become more constant. A whale will typically repeat the same phrase of song over and over again for two to four minutes at a time. This is known as a theme, of which a collection makes a song. The whale repeats the same song, which may last up to 30 minutes and even last for days at a time.

The mechanisms used by whales to produce sound vary from one species to another. Most whales produce whale sounds by passing air through a structure in the head called the phonic lips. The lips vibrate as the air passes through it and these vibrations can be consciously controlled with great sensitivity. They pass through to the melon of the head, which shapes and directs the sound into a beam for echolocation. Once the air has passed the phonic lips, it enters the vestibular sac, where the air may be recycled back to be used for sound creation yet again, or to be passed out through the blowhole. All toothed whales, except for the sperm whale, have two sets of phonic lips; therefore they are capable of making two sounds independently. Baleen whales do not have phonic lip structures, only a larynx that appears to play a role in producing whale sound.

Marine creatures are largely dependent on sound for communication and sensation, as their other senses are limited due to their watery habitat. Environmentalists appear to be concerned about whales being harmed and not being able to find mates because of the increased noise levels at sea caused by ships and other sources. The humpback whale songs for instance are often disrupted and this causes immense panic in the group.