The Short Answer: Males Copy the Song of the Population Next Door
Male humpback whales sing long, structured songs, and males in a population generally sing versions of one shared, changing song. When a new version appears, neighbors pick it up. In a ten-year study of six neighboring populations in the South Pacific, new songs moved from one population to the next, almost always from west to east, and a song could get from eastern Australia to French Polynesia in about two years. [1] [2]
The researchers called this "cultural ripples" moving eastward. It is the first documented case of such repeated song change across many populations at this geographic scale. [1] The rest of this page looks at what a "song" is here, what a sudden song takeover looks like, and the part nobody has pinned down: where the whales actually hear each other.
Who Sings, and Why Every Whale in a Group Sings the Same Tune
Scientists believe that only adult males sing. A song can last from about five minutes to more than a day. Males sing in warm breeding waters in winter, and they also sing on summer feeding grounds and during migration. Why they sing is still debated. In breeding areas, researchers agree that song probably plays a part in mating, and in other places the reasons are argued over. [7] The 2011 study describes the song as helping with mate attraction and with how males sort themselves socially. [1]
What makes the song special is that it is not fixed. Within one breeding area, males sing the current version together, and that version changes over months and years. [7] A song that is replaced within a few seasons cannot simply be inherited, so it is understood to be learned from other whales. This is why scientists talk about whale song as a kind of culture: something learned from others rather than built into the animal. That is the reason the question of how songs spread is a real puzzle.
A Song Starts in Eastern Australia and Moves East, Population by Population
Researchers recorded songs from six neighboring populations across the South Pacific over about a decade (the paper itself says 11 years of data). New song types showed up in the west, then in the next population east, and so on. Songs moved in one direction, almost always west to east, and only one song moved west during the study. [1] [2]
Speed matters here. A song could travel from eastern Australia to French Polynesia in about two years. The east coast of Australia has a very large population compared with the others, and the researchers suggested that this might help explain why songs flow mostly eastward. That is a suggestion, not something they proved. [2]
The scientists also pointed out how new songs usually arrive: most new versions blend older material with something new, but once in a while a completely new song appears, and it usually takes over within one breeding season. [2]
When a Whole Population Swaps Its Song in Two or Three Years
The most dramatic case was recorded off southeast Queensland, Australia, between 1995 and 1998, and it was published in Nature in 2000. A team led by Michael Noad analyzed 1,057 hours of song. In 1995 and 1996, the song changed only modestly, but two whales sang an entirely different song. In 1997, more whales used the new song, and some sang an in-between mix of both. By 1998 only the new song was heard. [4]
Where did the new song come from? It nearly matched what whales off Australia's west coast had sung in 1996. Scientific American reports that the researchers concluded a few west-coast singers had probably joined the east-coast population; how the song then took over is not something I could check in the paper. The authors called the change unprecedented in animal cultural vocal traditions, and they suggested that novelty itself may drive song change. Researchers now call such complete swaps "song revolutions." [4] The idea that novelty is attractive is a suggestion, not a measured result.
Do New Songs Get Harder or Easier After a Revolution?
Another team followed the eastern Australian population for 13 years in a row. In that population and study period, songs became more complex during years of slow, small changes. During revolutions, when the population fully replaced its song with new material from the Western Australian population, songs became simpler. [5]
The authors offered two explanations, and both are ideas rather than conclusions. Whales may have a limit on how much complex new material they can learn socially at one time. And small additions may be "embellishments" that let a male stand out in a group where nearly everyone sings the same pattern. [5]
Where Do Whales From Different Populations Hear Each Other? Nobody Is Sure
This is the biggest open part of the story. Different populations spend winter in different breeding areas, often thousands of miles apart. The 2011 researchers suspected one of two things: a few males move between populations and carry songs with them, or whales from nearby populations hear new songs while migrating together. They did not confirm how songs travel. [2]
One clue comes from the Southern Ocean near Antarctica. In 2010, researchers recorded a humpback song on a summer feeding ground there. The song had at least four distinct themes, and the same four themes appeared in the eastern Australian song from 2009 and in a New Caledonian song recorded later in 2010. The authors say this supports at least one proposed route: whales singing on shared summer feeding grounds. They suggest feeding grounds may be a meeting point where songs can pass quickly between populations. [3] This is a clue from one set of recordings, not a final answer, and other routes may work too.
How Far East Did the Songs Go, and Does It Happen in Every Ocean?
In 2022 a research team compared song themes from French Polynesia (recorded 2016 to 2018) with songs from Ecuador (recorded in 2018) and found matches. They read this as the eastward spread continuing across the whole South Pacific. [6] The match is the observation; the idea of a continuing chain is the authors' interpretation.
It is not yet clear whether other oceans behave the same way. This page does not cover other ocean basins because I did not verify those studies in English-language sources.
Try It: A Humming Game That Shows How a Tune Changes as It Is Passed Along
Ask four or five people at home to join you. The first person hums a short tune three times while the next person listens. Then that person hums it to the next, and so on down the line. If you are on your own, record a tune and try to copy it a day later. Compare the last person's tune with the first. Where did it change? Do it again and see whether the changes happen in the same place. Real whale songs are far longer and more complicated than a hummed tune, so this only gives a hint of how copying can slowly change a song.
To go further, search for humpback whale song recordings on the websites of NOAA, aquariums, or science museums, and read the first source below. Scientists keep finding new things, so the parts called guesses here may change.