Just like us, humpback whales succumb to musical fads. Every few years, all the males in one part of the ocean will swap their complex chorus of squeaks and moans for an entirely new one.
This new tune will ripple across the waves, to be adopted by other males separated by thousands of miles — much farther than the song can carry in the water. One humpback melody is displaced by another, much as today’s hit single dislodges yesterday’s No 1.
Until now, how the whales shared their music was a mystery. One theory had suggested it was down to lone troubadour humpbacks who swam between breeding groups, carrying their musical motifs with them.
One humpback melody is displaced by another, much as today’s hit single dislodges yesterday’s No 1.
New research suggests that the answer involves something more rousing: a kind of mass, multicultural whale jam session. As they head south towards the Antarctic after the breeding season, it has been discovered that humpbacks make a detour to a remote set of islands in the South Pacific. Several migratory corridors overlap here, bringing whales together from eastern Australia, New Caledonia, Tonga, Niue, the Cook Islands and French Polynesia. It appears that they linger for days, singing.
It was already known that the songs, which are performed only by males, are transmitted eastwards across the South Pacific, between breeding populations from Australia to French Polynesia — a distance of nearly 4,000 miles.
The new research, published in the Royal Society journal Open Science, focuses on the remote Kermadec Islands, about 500 miles northeast of New Zealand, a recently discovered migratory stopover for humpbacks as they swim south from their breeding grounds toward Antarctic waters.
The researchers, led by Ellen Garland from the University of St Andrews, analysed the music made by dozens of whales at the Kermadecs. Fragments of song recorded there also appeared in whale songs recorded from New Caledonia to French Polynesia.
Luke Rendell, also from the School of Biology at the University of St Andrews, said: “Song themes from multiple wintering grounds matched songs recorded at the Kermadecs, suggesting that multiple humpback whale populations from across the South Pacific are travelling past these islands and song learning may be occurring.
“Our results are consistent with the hypothesis of song learning on a shared migratory route, a mechanism that could drive the eastern transmission of song across the South Pacific.”
“Our results are consistent with the hypothesis of song learning on a shared migratory route.”
Behaviour that might be described as cultural — meaning that it is passed on and learnt — has been reported in hundreds of studies of animals as diverse as apes, birds and bees.
However, singing is a relatively rare trait. Among mammals, gibbons and mice do it but their songs are typically repetitive and simple — not at all like the humpbacks’ eerie, complex melodies.
Male whales are thought to sing to attract females and to communicate with other males. A previous study found that males in one area will converge on the same melody during the winter breeding season. This tune will gradually become more complex as individuals make embellishments, which are adopted by the group.
Every three years or so, the slate is wiped clean: a totally new song is adopted in what scientists call “a cultural revolution”.