Humpback whale songs are fascinating to humans. Apparently, the animals do not always sing the same song, but are constantly learning new songs very carefully. This is shown by a study from Australia.
Humpback whales are true song artists – and, according to new findings, they pick up the latest hit very quickly and precisely from their fellow whales. They learn different types of singing with great accuracy, regardless of the complexity of the pattern, report scientists in the journal “Scientific Reports”. The team had studied in detail the transmission of songs from one humpback whale population to another.
“We found that they actually learned exactly the same sounds without simplifying or omitting anything,” said lead author Jenny Allen of the University of Queensland’s Moreton Bay Research Station in Dunwich. “And every year that we observed them, they sang a different song. This means that humpback whales can very quickly learn an entire song pattern from another population, even if it’s complex or difficult.”
Humpback whales are known for their long, complex songs. These are not innate, but learned. The males usually sing to attract females, especially during the breeding season. Individual sounds are arranged in sequences called phrases. These are repeated several times and form a so-called theme. The themes are sung in a consistent order without repetition – creating the classic song of a humpback whale.
Such a song can change in small steps (evolutionary), which all other singers adopt through social learning – or a completely new song can conquer the population (revolutionary). In the South Pacific humpback whales, song patterns are transmitted from the Western Australian population first to eastern Australia, then to New Caledonia, Tonga and American Samoa, and on to the Cook Islands and French Polynesia. New “underwater hits” keep spreading around the world.
The researchers working with Allen included six different songs in their analysis that were passed on from humpback whales on the Australian east coast to conspecifics on New Caledonia between 2009 and 2015. Among other things, the number of tones produced and the length of the sound patterns were measured. Four of the songs were evolutionary changes, two were revolutionary – that is, completely new – songs.
Regardless of the complexity, the New Caledonian whales appropriated the songs with great attention to detail, the research team found. The songs are therefore probably learned on common migration routes or in common feeding areas such as in the Antarctic. The transmission of song is an extraordinary example of cultural transmission of a skill.
But why do the New Caledonian whales learn from the East Australian ones and not the other way around? According to the researchers, one of the reasons for this could be that the population in eastern Australia is much larger and thus includes significantly more potential inventors of new song sequences – and at the same time more males who then spread the new songs. Sounding nicer or completely new could be a criterion for success when choosing a partner.
Across the South Pacific, the western Australian population is the largest, followed by smaller eastward populations, the study notes. It has also been shown that population size influences song learning in other species such as the highly endangered honeyeater, whose population decline is accompanied by a severe loss of song culture.
Humpback whales (Megaptera novaeangliae) are found in all polar to tropical seas. They stay mainly on the open sea, but are also found near the coast, especially in the breeding areas. The animals are considered the acrobats among the large whale species: they show spectacular leaps and often hit the sea surface with their pectoral and tail fins. More than ten meters in length and 30 tons in weight are possible. Characteristic are the long pectoral fins, called flippers, which reach a third of the body length.
Humpback whales are also known for their amazing fishing techniques. For example, when they spot a shoal of fish or krill and are circling around it, they let air bubble up in bubbles. The prey does not swim through this curtain of bubbles – and is devoured by the whales advancing from below with their mouths wide open.
