Humpback whale song is structured in a similar way to human language – with shorter sounds used far more often than more complex ones – a structure which helps infants quickly learn how to communicate from their elders in both species.
Across languages and whale song, some words, or word-like elements, are used frequently while others are infrequent. They follow a pattern known as “Zipfian distribution”, where the most used word in a language (like “the”) is used about twice as often as the second most common word, and three times as frequent as the third most common word and so on.
All human languages – whether written, spoken or signed – share these common properties that help them be transmitted from one generation to the next.
Researchers detected word-like elements while analysing eight years of humpback whale recordings from New Caledonia, finding whale song shared the same characteristic fingerprint that makes human languages learnable, publishing their discovery in Science.
Dr Jenny Allen, an expert in whale song structure at Griffith University and co-author of the paper, said one of the things that made humpback whales so fascinating was how often their song changed and how quickly whales were able to learn a new song.
“Human language and whale song are both culturally learned, so whales learn the songs from the other whales that they spend time with. So that’s why all the whales in one population will be singing the same song,” she said.
“The only other species where you see learning on that spatial scale is in humans.”
The unexpected discovery of parallel structures in human language and whale song was made possible by a unique collaboration between marine biologists, behavioural ecologists, scientists and linguists.
Prof Simon Kirby, an expert in language evolution at the University of Edinburgh and co-author of the paper, said insights about infant learning were “the key that unlocked this discovery”.
He said human babies used an approach called “statistical learning” in order to identify words in the continuous stream of language that they’re exposed to. “It sounds technical and complicated,” Kirby said, “but actually it’s beautifully simple.”
Babies noticed that sounds within words were often stuck together, and more predictable than across word boundaries. “If you think of a word like ‘baby’, after a ‘bae’ sound, ‘bee’ is a relatively predictable continuation of that sound.”
The researchers used these insights to identify the word-like sound elements in whale song.
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Once the researchers applied this infant-inspired analysis to the recordings of whale song, they found other parallels, including that the patterns of word use in human languages matched the statistical patterns of sound elements in humpback whale song.
The researchers emphasised that their discovery was about structure, rather than content, and people would not be able to “speak whale” anytime soon.
Human language and humpback whale song served very different roles, Allen said.
“Whale song, we believe, is a reproductive display, because it’s only males that sing, and they primarily sing to and from the breeding grounds.”
She said even when the song became complex, these were probably “embellishments to impress the ladies or intimidate the guys”.
Humpbacks were like the “Pavarottis of the sea”, said Dr Vanessa Pirotta, a whale scientist who was not involved in the study. Male humpback whales had an amazing ability to produce a variety of sounds, she said.
Pirotta said earlier research had found evidence of specific vocalisations and themes being transmitted between different groups and generations, and even across oceans.
“The hottest 100 on the east coast this year might be the hottest 100 across the ditch in New Zealand the next year,” she said.