Language has long been considered a uniquely human trait, with features that mark it out as distinct from the communication of all other species.
However, research published today in Science has uncovered the same statistical structure in humpback whale song that is a hallmark of human language.
Dr Jenny Allen is a leading expert in whale song structure from Griffith University's Southern Ocean Persistent Organic Pollutants Program (SOPOPP) in the Centre for Planetary Health and Food Security.
Dr Allen worked with an international team, led by Professor Inbal Arnon of the Hebrew University, Dr Ellen Garland of the University of St Andrews, and Professor Simon Kirby of the University of Edinburgh, in collaboration with Dr Claire Garrigue (IRD New Caledonia), and Dr Emma Carroll (University of Auckland).
This work represented a unique collaboration between linguists, developmental scientists, marine biologists and behavioural ecologists.
The team applied innovative methods inspired by how babies discovered words in speech to eight years of humpback whale recordings collected in New Caledonia, uncovering the same statistical structures found in all human languages.
The findings also revealed previously undetected structures in whale song, illustrating a deep commonality between two unrelated species united by the fact their communication systems were culturally transmitted.
"Humpback whale song is culturally transmitted on a geographic scale not seen outside of humans, yet they are evolutionarily quite distinct from us."
Dr Jenny Allen
"This is why it provides such an exciting comparison."
"These results give us unique insight into the importance of cultural transmission in learning processes across species, particularly for learning complex systems of communication."
"Rather than trying to fit animal communication into a 'human language' shaped hole, I think the more interesting question is "why did such different communication systems evolve such similarities?"
Human language, which is also culturally transmitted, has recurring parts whose frequency of use follows a particular pattern.
In humans, these properties help learning and may come about because they help language be passed from one generation to the next.
Prof Inbal Arnon from the Hebrew University said "using insights and methods from how babies learn language allowed us to discover previously undetected structure in whale song".
"This work shows how learning and cultural transmission can shape the structure of communication systems: we may find similar statistical structure wherever complex sequential behaviour is transmitted culturally.
"It raises the intriguing possibility that humpback whales, like human babies, may learn their song by tracking transitional probabilities between sound elements, and using dips in those probabilities as a cue to segment the song."
The study 'Whale song shows language-like statistical structure' has been published in Science.
