Woods Hole, MA - Recordings of male humpback whales have shown that their haunting songs spread through the ocean to other whales.
Researchers in Australia listened to hundreds of hours of recordings gathered over more than a decade.
These revealed how a specific song pattern, which originated in Eastern Australia, had passed "like Chinese whispers" to whale populations up to 6,000km away in French Polynesia.
The findings are reported in the journal Current Biology.
The research team, led by Ellen Garland from the University of Queensland, say the findings show the animals transmit such "cultural trends" over huge distances.
All it takes is a few roving males acting as cultural ambassadors to spread their songs.
"Within a population, all males sing the same song," Ms Garland explained. "But that song is constantly changing. So we wanted to look at the dynamics of songs throughout an ocean basin."
To do this, she and her colleagues studied recordings of 775 humpback whale songs, taken by scientists from the South Pacific Whale Research Consortium.
"Lots of different sounds make up each song," Ms Garland explained.
"There are low frequency moans, groans and growls then higher cries and shrieks and all variations of ascents and descents."
Patterns of these sounds make up phrases, and the whales repeat the phrases - like repeated verses - for up to 30 minutes.
Using sound analysis software, Ms Garland and her colleagues discovered that four new songs that had emerged in a population in Eastern Australia gradually spread eastwards.
Within two years of this new song being invented, whales in French Polynesia were singing this same "version".
"It's a culturally-driven change across a vast scale," said Ms Garland.
The researchers think the whales in the South Pacific may hear and learn songs during their annual migration to their feeding grounds in Antarctica.
"The East Australian population is the largest in the region with over 10,000 humpbacks," Ms Garland explained. Since there are more of them singing, these whales may have more influence on what songs "catch on".
Peter Tyack, a biologist from Woods Hole Oceanographic Institution in Massachusetts, US, said the results showed "a new way to look at culture in these animals".
The mammals produce the sounds by forcing air through their nasal cavity.
"These are very mobile animals; they can swim hundreds of kilometres in a day... and their song carried very well underwater," he said.
"So all it takes is a few roving males acting as cultural ambassadors to spread their songs [from population to population]."
Although there is still some debate whether male humpbacks' songs are directed at females or each other, most scientists agree that the song plays a role in reproduction.
Dr Tyack explained: "We have good behavioural observations of singers competing with each other and of females moving to join the singers, so we think it's associated with mating."
Dr Patrick Miller from the Sea Mammal Research Unit at the University of St Andrews, UK, said that this study suggested that "some large-scale, previously undetected, factors drive the year-to-year changes in humpback song".
"We can only begin to speculate what those factors might be, but exploring this will certainly open a new understanding into the lives of these truly cosmopolitan, singing giants."
--- In MARINE_BIOLOGY_INTERNATIONAL@yahoogroups.com, "MalcolmB" <malcolmb2@...> wrote:
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> Swimmer-songwriters: Whales have their own tunes that spread around the world 'like hit singles'
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> By David Derbyshire
> Last updated at 9:10 AM on 15th April 2011
>
> When Lady Gaga releases a catchy new single, it quickly goes around the world.
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> Now scientists have discovered the same thing happens with the songs of another exotic creature – the humpback whale.
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> The mammals become fixated on new tunes just like people do, and the most popular original whale songs spread globally like hit singles.
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> The discovery has stunned marine experts who say it is the first time such a large, `population wide cultural exchange' has been seen in the animal kingdom.
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> Male humpback whales are famed for the loud, long and complex songs they make during the mating season. Scientists are unsure why the males sing. Some believe it is a way of advertising themselves to females, others that it allows migrating whales to stay in contact.
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> Each song lasts for ten to 20 minutes and the males can sing continuously for 24 hours.
> At any one time, all the males in a population sing the same song.
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> But a study, published in the journal Current Biology, shows that this song changes over time and spreads around the oceans. Dr Ellen Garland, of Queensland University, said: `Our findings reveal cultural change on a vast scale. Songs move like cultural ripples from one population to another, causing all males to change their song to a new version.'
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> Researchers recorded songs from six neighbouring populations of whales in the Pacific over a decade. They found that new versions of the songs appear over time and always spread from west to east.
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> It takes two years for songs that appear in the waters off Australia to be heard in French Polynesia.
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> It takes around two years for songs that appear in the waters off Australia to be heard in French Polynesia
> Dr Garland believes that a small number of whales may migrate to other populations carrying the new songs with them, or that they are heard by passing whales.
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> Most of the new songs contain material from the previous year blended with something new.
> `It would be like splicing an old Beatles song with U2,' she said. `Occasionally they completely throw the current song out of the window and start singing a brand new song.'
> The researchers suspect whales adopt new songs to make themselves distinct. Dr Garland said: `We think this male quest for song novelty is in the hope of being that little bit different and perhaps more attractive to the opposite sex. This is then countered by the urge to sing the same tune, by the need to conform.'
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