Alison Potash, Tracy Roese, and Shannon Johnson

There is a long history behind Humpback Whales. Their scientific name, Megaptera novaeagliae, means in Latin terms "big- winged New Englander." Humpbacks grow to about 40-50 ft. and can weigh up to approximately 30 tons fully grown. When they are born they are approximately 10-12 feet and 2000 lbs. Adult Humpbacks eat up to 3000 lbs. of food per day, during the 6-9 months they are on their feeding grounds. They eat small fish and some krill. However, Humpback calves nurse from their mothers gaining 60 lbs. per day. While Humpbacks are on their breeding grounds they do not feed because there is little food available. They fast and live off their fat.

Humpback Whales are found in three distinct locations in large populations. They are found in the North Atlantic, North Pacific, and the Southern oceans. These populations have similar migration routes from breeding grounds to feeding grounds. They also form social organizations. In some rare cases Humpbacks will stay together for weeks or months. Usually they split up after 30 min.- 24 hrs.

A Humpback Whale’s life span is 40-50 years, perhaps longer. Their biggest threats today are getting caught in fishing gear, collisions with ship traffic, and pollution. To listen to Humpback Whale songs visit http://fas.sfu.ca/cs/research/projects/whales/.

The exact mechanism for the production of sounds by large baleen whales is not known. Like other mammals, whales have lungs that drive air through the trachea and larynx (Clark, 1991). There are no vocal chords in the mysticete larynx, but there is a constriction between the back of the larynx and the trachea that could serve as the origin of the sounds given by the large whales. When baleen whales vocalize, they do not expel air from their mouths of nostrils (blow holes). This indicates that the air used for making the sounds is contained within a closed system.

The Humpback is best known for its vocalizations, which cover many octaves. The song is a series of moans, groans, squeaks, and clicks (Ellis, 1980). It is a complicated series of sounds lasting from 5 min. to a half hour, with a frequency range of 40Hz to 5kHz and can be detected by hydrophones over 30 km away (Evans, 1987). Song sessions can continue through the day and night with only brief one minute pauses for breath. Howard and Lois Winn ( 1987) recorded one whale in the Caribbean singing non stop for at least 22 hours.

Humpback songs, apparently sung by lone males, last as long as 20 min. after which they are repeated, often with slight changes (Balcomb, Foster, and Minasean, 1940). Within one season all the whales within a particular region sing broadly the same song. All individuals of a population change their songs in the same way. The changes are both progressive and rapid, each component changing every two months (Evans, 1987). Every winter’s song is a modified version of the previous years song and all the whales seem to have learned the changes and sing the new version of the song. An entire song is changed about every eight years.

The whales sing only when they are in their mating areas and not when they occupy the cold- water feeding grounds, defining the singing as a warm water activity (Ellis,1980). The sounds may be used to advertise the presence of a breeding male to warn off potential rivals, or perhaps to establish herd contact with other whales throughout the wide expanse of their breeding grounds.

When Humpback singing was first observed it was considered to be a type of mating ritual with the female choosing the more complex or different song. It was assumed that the lone adult singer was a male, and he would sing until joined by another lone adult, or he would leave and join a larger mating group. When he was joined by another lone adult they would either pair up and swim off, immediately move apart, or they would engage in fights. The variance in this behavior suggested that there might be more to the singing then just a mating ritual(Darling, 84).

Studies Done by Roger Payne and Jim Darling in Hawaii uncovered some interesting facts about the Humpbacks in their breeding grounds. Flip Nicklin, an expert free diver and photographer for National Geographic, developed a technique for photographing the singers under water. Singers generally dive to just below the surface and stay motionless with their head down and tail up at a forty-five degree angle(Earle, 79). Flip was able to dive below the whale, holding his breath so as not to tickle the whales belly with the bubbles, and take pictures of the genital slits to determine the sex. Through this technique it was proven that the lone singers were indeed males. Using this information plus photos taken of the other humpbacks in the area, a file of all the known males and females in the area was built up. This is how it came to be discovered that the lone adult joining the male singer was often a male rather then female as originally thought. This made the mating ritual theory even more puzzling, since why would the song be attracting males (Darling, 84)?

As explained earlier, humpbacks change their songs every year; that is the whole population changes in the same ways. They seem to compose as they go along, incorporating new elements into the old songs( Payne, 91) Songs years apart are as different as night and day, while the ones from year to year are more alike. This seems to show that the song is evolving from year to year, and the song becomes more and more complex (Payne, 79) This along with the emerging observations of violent behavior between the humpback males led to the start of a new theory. It was discovered that descriptions of mountain sheep mating-competitive groups closely resembled that of the humpbacks. Another comparison was drawn between the songs of the humpback and the horns of the mountain sheep. Horns are examples of secondary sexual characteristics of male mammals, with the individuals position of dominance being directly related to the change or growth of the horns. They are visual displays that are used to maintain an order of dominance with fights occurring only when the dominance displays are not obvious. A comparison can be drawn then between the horns of the mountain sheep and the songs of the humpbacks. Because whales live in the ocean environment visual displays of dominance would be difficult since there is often low visibility underwater, and having them would take away from their efficiency of movement in the water. If the humpbacks are using their songs as a form of dominance it would explain why it evolves from year to year, and why each population sings the same song. They would have to have some common criteria to judge each other by. It would also help to explain the frequent fights observed between the males in the breeding grounds( Darling, 84).

Unfortunately there is no definite reason as to why or how the humpbacks sing, and this paper has only touched on a few of the theories that have been developed throughout the years. Along with many complicated theories there have been some very uncomplicated ones. Mark Roth believed that the "songs" we hear are actually the sounds of the humpback stomachs growling. This would explain why the "songs" are mostly heard in the breeding grounds, since this is where the whales eat the least. The fact that the sound can be heard for miles would be explained by the fact that the whale is so large, and that the sound would be heard further in water since it is denser then air(1980). The humpback’s song is still a mystery, a wonder of the ocean that may stay unexplained for quite some time.

Clark, Christopher W. (1991). Talking Heads. Natural History. , 3: 42.

Darling, Jim. (1984). Source of the Humpbacks Song. Oceans. 17:3-10.

Earle, Sylvia A. (1979). The Gentle Whales. National Geographic. p.2-17.

Ellis, Richard. (1980). The Book of Whales. Alfred A. Knoff, NY. p. 65-66.

Evans, Peter G.H. (1987). The Natural History of Whales and Dolphins. Facts on File Inc., NY. p. 189- 193.

Minasion, Stanley M. et al. (1940). The Worlds Whales. W.W. NoAon & Company, NY. p. 56.

Payne, Katy. (1991). A Change of Tune. Natural History. 3:45.

Payne, Rodger. (1979). Their Mysterious Songs. National Geographic. p.18-25.

Roth, Mark. (1980). The Resounding Humpbacks. Oceans. 13:51.

http://fas.sfu.ca/cs/research/projects/whales/

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