Whale song has structure similar to human language
The Hebrew University of Jerusalem
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Humpback whale song is a striking example of a complex, culturally transmitted behavior, but up to now, there was little evidence it has language-like structure. 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. This work innovatively applies methods inspired by how babies discover words in speech to humpback whale recordings, uncovering the same statistical structures found in all human languages. It reveals previously undetected structure in whale song, illustrating a deep commonality between two unrelated species united by the fact that their communication systems are culturally transmitted.
Whale song has language-like structure
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 that is a hallmark of human language in humpback whale song.
Humpback whale song is a striking example of a complex, culturally transmitted behavior, but up to now, there was little evidence it has language-like structure. 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. This work innovatively applies methods inspired by how babies discover words in speech to humpback whale recordings, uncovering the same statistical structures found in all human languages. This work reveals previously undetected structure in whale song, illustrating a deep commonality between two unrelated species united by the fact that their communication systems are culturally transmitted.
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), Dr Jenny Allen (Griffith University), and Dr Emma Carroll (University of Auckland), this work represents a unique collaboration between linguists, developmental scientists, marine biologists and behavioural ecologists.
Humpback whale song is one of the most striking examples of a socially learned, culturally transmitted behaviour in a nonhuman animal. Whale song exhibits systematic structure, however, until now, there was little evidence that this structure was like that of human language. One of the big challenges in studying non-human communication is finding out what the relevant parts of the system are. The authors’ breakthrough was to use insights from how babies discover words in speech, and apply them to eight years of humpback whale song data collected in New Caledonia. The authors found that whale song showed the same key statistical properties present in all known human languages. They detected recurring parts whose frequency closely followed a particular skewed distribution, not previously found in any other non-human animal. This work reveals a deeply unexpected commonality between two unrelated species - humans and humpback whales - united by the fact that their communication system is culturally transmitted. This points to the crucial role of learning and transmission in the emergence of structure within such systems. Once thought of as the hallmark of human uniqueness, foundational aspects of human language may be shared across evolutionary distant species.
Dr Ellen Garland from the University of St Andrews said: “Revealing this hidden language-like structure in whale song was unexpected, but it strongly suggests this cultural behaviour holds crucial insight into the evolution of complex communication across the animal kingdom.”
“Whale song is not a language; it lacks semantic meaning. It may be more reminiscent of human music, which also has this statistical structure, but lacks the expressive meaning found in language.”
“Whether the units we detected using the infant-inspired method are salient to the whales themselves remains an open question.”
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”
Prof Simon Kirby from the University of Edinburgh said:
“It suggests that our understanding of the evolution of language can benefit not only from looking at our closest primate relatives, but also at cases of convergent evolution elsewhere in nature.”
“Looking beyond the way language is used to express meaning, we should consider how language is learned and transmitted culturally over multiple generations.”
“These findings challenge long held assumptions about the uniqueness of human language, uncovering deep commonalities between evolutionarily distant species.”
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Journal
Science
Method of Research
Observational study
Subject of Research
Animals
Article Title
Whale song shows language-like statistical structure
Article Publication Date
7-Feb-2025
Some species of baleen whales avoid attracting killer whales by singing too low to be heard
University of Washington
Killer whales are the only natural predator of baleen whales — those that have “baleen” in their mouths to sieve their plankton diet from the water. More solitary than toothed whales, baleen whales face predatory attacks from killer whales, especially mother and calf pairs. When attacked, some species fight back, while others choose flight.
But whale species also produce loud underwater songs. What stops killer whales from homing in on their calls and attacking them?
New research from the University of Washington finds some baleen whale species call at such deep frequencies that they’re completely undetectable by killer whales, which cannot hear sounds below 100 hertz. These tend to be the whale species that flee in the face of attack. These deep singers in the “flight” club include blue, fin, sei, Bryde’s and minke whales.
Meanwhile, their higher-frequency singing brethren that fight back when attacked also tend to be slower-moving and more maneuverable. The “fight” club includes right, bowhead, gray and humpback whales.
The research was published Jan. 31 in Marine Mammal Science.
To conduct the study Trevor Branch, professor of aquatic and fishery sciences at the UW, conducted a review of aquarium experiments on killer whales’ hearing ranges, reviewed the source frequency and source level of populations of all baleen whales, and combined these with knowledge of how sounds move through the ocean to predict which whale populations can be easily heard by killer whales. It turns out the calls of flight species generally can’t be heard more than 1 kilometer away by killer whales, unlike the calls of fight species.
The fight or flight hypothesis is not new, but research into acoustics is shedding new insights into adaptations of baleen whales. Could this so-called acoustic crypsis, where whales that call at such deep frequencies that they are acoustically invisible to killer whales, have developed as a defense mechanism from attack?
Killer whales are found in all the world’s oceans, and killer whales’ prey ranges from small fish to the largest whales on Earth. The fight species of baleen whales usually migrate and calve closer to the coast in shallow water, a haven of sorts that provides easier defense against killer whale attacks — especially for group defense in aggregations. Combined with their slow-swimming and more navigable bodies, their communication with other whales is often at higher frequencies easily heard by killer whales — above 1,500 hertz. In contrast, flight species have streamlined and slender bodies adapted for speed, and typically disperse across wider open-ocean regions for mating and calving, where they are able to flee in all directions.
These behaviors also have implications for feeding and mating. Denser congregations in shallow coastal areas leave less food for fight species, in comparison to the open ocean favored by flight species. However, the opposite is true for finding a mate — it’s easier when you’re all in a similar location, versus spread out over long distances.
Singing is a fundamental part of mate attraction and selection for whales. Males of the flight species sing in a way that maximizes the number of females that hear them, producing simple and repeated songs to attract a potential mate, and singing over prolonged periods to allow females to track them down.
“But these super-loud songs could expose them and their mates to killer whale attack. And this is where acoustic crypsis comes in: singing at low frequencies that are impossible, or very difficult, for killer whales to hear,” Branch said.
The research shows that under the sea there is a sound landscape governed by fear, with some whale species choosing to sing their songs to their prospective Valentines at deep levels to avoid attacks; while other whale species compete to sing the most varied and interesting songs, and fight back when attacked. The fight vs. flight differences appear to drive all aspects of the lives of baleen whales, from where they are found, to their communication, to where and when they breed and feed.
“It just never occurred to me that some whales sing low to avoid killer whales, but the more I looked at this, the more I realized that every aspect of their behavior is influenced by the fear of predation,” Branch said.
For more information, contact tbranch@uw.edu
Journal
Marine Mammal Science
Method of Research
Literature review
Subject of Research
Not applicable
Article Title
Most “flight” baleen whale species are acoustically cryptic to killer whales, unlike “fight” species
