By Anuradha Rao and Caitlin Birdsall
All you shower singers out there have some serious competition from the vocalists of the world’s biggest bathtub!
Many of us have already heard about – and heard – the songs sung by humpback whales. These incredible vocalizations were first described by Roger Payne and Scott McVay when they published an article in Science in 1971 after their discovery that humpbacks ‘sing’. Payne also published an article in National Geographic magazine that contained a record of whale songs –haunting melodies that took the world by storm, with 10.5 million copies printed.
Since then, researchers have discovered fascinating characteristics of whale songs, including the transmission of songs through “cultural” means. That is, males in the same population sing the same song and their song changes almost simultaneously over the course of a season. The song changes after individuals begin to make modifications, which are then adopted by the rest of the population.
In the field of animal behavior it is thought that animals use songs for one of several reasons: to announce themselves to other groups of the same species, to assert dominance, or to attract mates. Male humpback whales sing long, complex songs while migrating from summer feeding grounds to winter breeding grounds and while at these breeding grounds. While humpback songs have been studied for over 30 years, the reason why they sing these songs is not yet well understood
As it is the males of the humpback whale species that are the singers, it is assumed that the songs are used either for asserting dominance over other males or in mate attraction. In other words, do the males try to out-sing each other, or do the gals fall for the musicians?
Researcher Josh Smith and his colleagues in Australia have been tackling these questions, and published a paper in Animal Behaviour in 2008. They observed that male humpbacks sang while escorting females – in particular, mothers with calves. The songs may demonstrate to females that the singer is particularly fit. There is some evidence that a male humpback that escorts a mother and her calf ends up being the father of that female’s next calf. It is not yet known, however, if females are particularly attracted to singers, but evidence from Australia shows that males sing most often in the presence of mother-calf groups.
This research group also found little evidence for male-male song competition. They observed that while singers did seem to attract other males, the singer stopped singing when another male joined their group. This isn’t what one would expect if whale songs are used by males to compete with each other. Instead, Smith et al suggest that songs may inadvertently indicate to other males that a female is present, and they may in turn ‘prospect’ for females by joining singing males.
Whether these insights apply to all humpback populations is still not clear and it is evident that the function of the humpback song continues to present a bit of a mystery. On this other side of the world, in the north Pacific, humpback songs are being studied in Hawaii, Mexico and other breeding areas, as well as increasingly in British Columbia. With the comeback of humpback whales to the B.C. coast, humpback songs are now being detected by hydrophone networks, especially in the fall. How much singing happens, its timing and purpose in the northern feeding areas is not yet well understood. You can help humpback researchers in B.C. by reporting your sightings of humpback whales here. Your contribution to understanding their year-round abundance and distribution could one day help us to understand why humpbacks are singing in B.C.
Want to learn more?
-Listen to a humpback song recorded by researchers at Cetacealab, on B.C.’s central coast, here.
-Read the paper: Smith, J.N., A.W. Goldizen, R. A. Dunlop, and M.J. Noad. 2008. Songs of male humpback whales (Megaptera novaeangliae) are involved in intersexual interactions. Animal Behaviour 76: 467-477.
-Discover more about the return of humpback whales in southern British Columbia in 2009 here.