loading . . . Talking whale: the quest to decode their secret code October 4, 2025
### Drew Rooke
By Drew Rooke
### The ocean’s unique soundscape includes a vast array of distinctive whale vocalisations. Drew Rooke wonders whether we can ever truly decode the language of these majestic giants. This article was originally published in the Cosmos Print Magazine, September 2024.
When Shane Gero first travelled to Dominica in January 2005 to study the sperm whales who live in the sparkling, squid-rich waters that surround the Caribbean island-nation, he did not anticipate how transformative the trip would be. “I thought we were just going to go there for that one season,” he says, laughing.
Back then Gero was a young master’s student at Dalhousie University in Canada. He had loved whales and had dreamt of becoming a marine biologist ever since he was a small child and now, he was living out his dream.
Accompanying Gero were his supervisor, biologist Dr Hal Whitehead, and several other graduate students – all living and working together aboard Balaena, Whitehead’s 40-foot cutter-rigged sailboat. They had chosen the waters around Dominica as a research site after learning that there were many more young whales in family units there than elsewhere. “And I wanted to study what it was like to grow up sperm whale,” Gero says.
As it turned out, there was no better location in the world to do so. For 41 consecutive days, the group sailed alongside one family of sperm whales – nearly triple the longest amount of consecutive time Whitehead, who was one of the foremost sperm whale researchers in the world, had spent in the company of these ocean nomads.
“I’d love to tell you that it’s my acumen as a biologist, but we just kind of found this amazing place to study these amazing animals,” Gero says.
To continue his research, Gero founded the Dominica Sperm Whale Project and began making regular trips to Dominica to study its resident cetaceans. He hasn’t stopped: these days, he spends roughly three to four months every year in the field to continue working on his long-running research program, which over the last two decades has collected the largest sperm whale data repository in the world.
“We’ve seen calves born and have followed them through weaning. Each time we go back we notice particular individuals have grown up, or that they suddenly have new marks on their bodies. They’re really part of our lives, kind of in the same way as a distant colleague or a friend that you only see once or twice a year,” says Gero.
Now he hopes to further deepen his connection with these gentle giants of the deep – by cracking the code of their complex communication system and maybe, just maybe, talking with them.
Shane Gero and team in Dominica. Credit: Courtesy of the Dominica Sperm Whale Project.
## Whales find their voice
Cetaceans appeared on Earth roughly 60 million years ago when their land-dwelling ancestors began to venture further from the shore, evolving traits to survive their new, aquatic home.
Over time their front limbs were replaced with flippers, while their obsolete hind limbs disappeared. Their tails grew wide and fluked, their bodies became insulated with a thick layer of blubber, and the haemoglobin levels in their blood swelled to enable more efficient storage of the precious oxygen they inhaled at the surface. In addition, this new order of mammals developed the ability to communicate with each other underwater.
Vocalisations are not uniform among different species. Toothed whales, such as sperm whales and dolphins, produce short sequences of clicks and whistles known as ‘codas’, by releasing a high-pressure blast of air which passes through a vibrating structure in their nose known as ‘phonic lips’.
In the case of sperm whales, these sounds are one the loudest single-source noises on Earth, reaching 200dB – equal to the 1967 launch of the Saturn V space rocket, and loud enough to burst a human eardrum – and help with echolocating and hunting prey in the deep, dark depths.
In contrast, the melodic songs of baleen whales such as humpbacks are produced as air passes from their lungs and through a U-shaped fold of tissue, causing it to vibrate. The resulting sound then resonates in an inflatable organ called the laryngeal sac.
## Speaking to scientists?
Communicating with these highly vocal and social marine mammals has been a long-held pipe dream of scientists – one that has historically attracted some eccentric personalities.
Most notable is American neuroscientist John Lilly, who in the late 1950s established the Communications Research Institute (CRI) on the shores of Nazareth Bay, on the eastern side of the island of St. Thomas, in the Caribbean Sea.
Up until that point, Lilly had conducted most of his pioneering – albeit highly unethical – research into brain function, behaviour and consciousness using monkeys and cats as experimental subjects. He had been interested in studying cetaceans since 1949, when he and two colleagues extracted the brain of a pilot whale which had fatally beached in Maine; its large size, he believed, indicated a high degree of cognitive complexity, equal to – or perhaps greater than – our own.
Lilly’s interest deepened throughout the 1950s when he made several visits to Marine Studios, an oceanarium in Florida, to conduct experiments on some of the bottlenose dolphins held captive there and heard for the first time their complex vocalisations.
These experiments proved fatal for many dolphins. But they proved life changing for Lilly, inspiring him to build “the world’s first laboratory devoted to the study of the intellectual capacities of the small, toothed whales,” as he wrote in 1959 to a friend at NASA, which soon thereafter provided funding for the CRI in the hope that its research would help lay the foundations for communicating with extra-terrestrial intelligence.
As well as studying the creaks, clicks and whistles of the captive dolphins at the CRI – which, in Lilly’s mind constituted a language he termed “dolphinese” – the research program at St. Thomas was aimed at teaching these animals a human language: “a primitive version of English,” as Lilly wrote in his 1961 bestselling book, _Man and Dolphin_.
This would require, Lilly reasoned, “constant and continuous attention and awareness of detail”. Therefore, one of his assistants, Margaret Howe, lived full time with a dolphin named Peter on the flooded and waterproofed second floor of the building, attempting to teach him basic words and phrases. Over time, Peter managed to produce sounds that bore some resemblance to English words (much like some parrots can) in exchange for fish treats but made little other progress.
These meagre results contributed to the CRI – and, by extension, Lilly – losing its scientific credibility and much of its funding. This decline rapidly accelerated when reports emerged that Lilly had dosed his captive dolphins with LSD to hopefully help them learn human language skills – and that Howe had manually relieved Peter of his sexual desires, which were becoming increasingly disruptive to the institute’s interspecies communication work.
By the end of the 1960s, the CRI had closed down. But Lilly continued his quest to communicate with cetaceans all the way up until his death in 2001, believing that the benefits of succeeding would be extraordinary.
As he wrote in 1978, “Let us learn to communicate with the ancient macrobiocomputers of the Cetacea and learn something of the complexities of their computational capacities. Such communication may enrich our lives beyond anything that we have heretofore conceived and may open up possibilities for the future evolution of man beyond his present limits.”
## Whale phonetics
Founded in 2020, the Cetacean Translation Initiative – Project CETI, for short – agrees with Lilly about the huge worth in learning to communicate with cetaceans. But it has taken a very different approach in its quest to achieve this.
Instead of using hallucinogenic drugs on captive whales and trying to teach them English, it is using the combined skills and experience of biologists, linguists, cryptographers, acoustic engineers, roboticists, computer scientists and artificial intelligence experts to try to understand their ancient communication systems.
Gero is the lead biologist on the project, and earlier this year he co-authored a study which he believes marks a significant step towards breaking the interspecies communication barrier.
Published in _Nature Communications_ , the study sought to shed new light on the communication system of sperm whales and was based on more than 8,700 sperm whale codas.
A breaching humpback whale in Alaska. Credit: Getty Images.
This enormous dataset had been collected as part of the Dominica Sperm Whale Project between 2005 and 2018 using towed listening devices plus sound tags placed on individual animals.
Analysing it manually – by trawling through reams of printed spectrograms, as scientists once had to do – was practically impossible. Instead, Pratyusha Sharma, a PhD student in the Computer Science and Artificial Intelligence lab at MIT and the lead author of the study, used a combination of statistical and machine learning methods to look for patterns and features within the whales’ click sequences.
This proved ground-breaking. It revealed, firstly, that sperm whales make fine-grained adjustments to their codas depending on the conversational context, such as adding an extra click – “kind of like a suffix”, explains Sharma – or varying the duration of their calls.
Secondly, the analysis found that the whales freely combine these variations to construct a repertoire of distinct vocalisations far larger than was previously believed. “And the interesting thing about combinatorial communication systems like this one is that there are not that many examples of it in the world,” Sharma says. One of the only other examples is human language. “We have alphabets that combine to form words and words that combine to form sentences, and that’s how we can use finite sounds to like express infinite meanings.”
The researchers catalogued these newly discovered variations into what they called a “sperm whale phonetic alphabet” – like the International Phonetic Alphabet for human languages – which they believe provides a foundation for future research into the semantics of whale calls.
## Acoustic exchanges
Key to the next stage of research are what are known as “interactive playback experiments”, which are already being conducted with some other whale species.
Most notably, in November 2023 a team of researchers from the SETI Institute, University of California Davis and the Alaska Whale Foundation, published the results of an interactive playback experiment they conducted with an adult female humpback whale named ‘Twain’ in southeast Alaska two years’ earlier.
The experiment involved broadcasting via an underwater speaker a high-quality contact call, known as a “whup” call, which had been recorded the previous day from a group of nine humpbacks. This attracted the attention of Twain, who approached and circled the team’s boat and began responding with her own call. This “acoustic exchange”, as the researchers described it, continued for 20 minutes.
Later analysis of the recording revealed that Twain was, as the study said, “actively engaged in a type of vocal coordination [with our playback system]… she was also exhibiting changes to both arousal and valence during the encounter.”
According to the study’s lead author, Dr Brenda McCowan, this marked an unprecedented step in interspecies communication research. “We believe this is the first such communicative exchange between humans and humpback whales in the humpback ‘language’.”
## Uncertain understanding
Not everyone agrees with the findings to date. There’s some contention among scientists about the significance of these recent studies with sperm and humpback whales, as well as about the possibility of interspecies communication more broadly.
In fact, when I ask Rebecca Dunlop – an associate professor in physiology at the University of Queensland who has been researching humpback bioacoustics for over two decades – if she thinks that we are on the cusp of being able to communicate with cetaceans, she chuckles and says bluntly, “nope”.
Dunlop acknowledges that interactive playback experiments can help determine the function of whale calls. But she dismisses the idea that scientists are in some way conversing with a whale if they broadcast a call and receive an engaged response, as happened with Twain. To claim this implies that “the whale heard them and then decided to say something back, like there was some cognitive decision making going on, which I think is a bit of a stretch.”
Instead, she sees the interactive playback experiment with Twain as demonstrating “an animal responding to a sound, as it’s pre-programmed to do”.
Dunlop is also sceptical of some of the claims made by the Project CETI team in their paper about a sperm whale phonetic alphabet. While she accepts that sperm whales’ clicks are very complex, she doesn’t believe that they can be equated to human language.
“Humans have evolved language with syntax, and we can change the meaning of a sentence by just putting words in a different order. How we use language is highly, highly complex, and other animals – as far as we know – are nowhere near that level complexity. They can use sounds to mean certain things. But to say that that’s a language is I think one step too far.”
Dr Jenny Allen – a biologist from the Bio-Telemetry and Behavioural Ecology Lab in the Department of Ocean Sciences at the University of California with more than 15 years’ experience researching humpback whales – has other criticisms.
There is, Allen says, “tremendous value” in conducting interactive playback experiments, adding that scientists have been conducting them with birds “for ages”. But to frame the one conducted with Twain as a kind of primitive conversation between humans and a whale makes the mistake of “pushing these animals through a human shaped hole”.
“Animals communicate to each other in such a variety of ways that are so different to what we know.”
Allen is also critical of how the Project CETI team characterised sperm whale vocalisations, noting that while the previously undiscovered features are “really fascinating”, the idea of a phonetic alphabet is “beyond the scope of the study”.
“It means that each individual component doesn’t have a meaning. And we can’t really say sperm whale codas by themselves have no meaning.”
Speaking more generally about the quest to translate whale vocalisations and talk with them, she says, “I worry that we’re so busy looking for signs that point to other animals being like us, rather than looking at the similarities that we do find and asking, ‘What does it mean for that species? What does it say about evolution?’”
But Josephine Hubbard, postdoctoral researcher in the Animal Behaviour Graduate Group at the University of California Davis who co-authored the study involving Twain, says that her team was “careful not to anthropomorphize our interpretation of the data, which is why we were very strict in how we define a communicative exchange.” She also emphasises that there is “robust evidence” the female humpback was engaged during the experiment.
“And we can debate about whether it was a conversation or not, but I think what’s worth highlighting is the fact that we are using and trying to promote these interactive playbacks.”
Likewise, Pratyusha Sharma of the Project CETI group disagrees with the criticisms levelled at the study she led. “We don’t make any claim that this formal communication system of sperm whales is like human language. But there are aspects of it that are similar.”
She also points out that the word ‘alphabet’ is widely used by scientists to characterise many complex structures, including DNA, and cites the example of the hieroglyphs to point out that in some alphabets, even the smallest units do indeed carry meaning.
Adding to this response, Gero insists that the Project CETI team isn’t “trying create a hierarchy which ends in humans. But I do think that we’re at a stage now where we can ask more detailed questions about animal communication.”
More broadly, he believes all of us should keep an open mind about the intellectual capacity of nonhuman species. “I think we do a disservice to whales if we assume they have some kind of stimulus-output quality, when we know that they have a brain that rivals ours at least in terms of the capacity for cognition.”
> “We don’t make any claim that this formal communication system of sperm whales is like human language. But there are aspects of it that are similar.”
>
> Pratyusha Sharma of Project CETI
## The desire to communicate
Many books have been written over the years that envision what it would be like if humans could communicate with other animals. Laura Jean McKay’s science fiction masterwork, _The Animals in that Country_ , in which a new virus emerges whose chief symptom is that its victims are able to understand what animals are saying, is one the wildest examples to date.
If science fiction does indeed one day become science and we manage to understand whales and how to communicate with them, I wonder what we might say?
I ask Sharma this question. After a few moments of trying to find an answer, she says, “You know, I would not say anything. I would just want to listen and hear everything they have to say about their world.”
Gero, likewise, sees Project CETI as being a “listening project” – which will hopefully enable us to better understand what’s important to whales and thus help conserve them.
“I feel very strongly as a scientist and just someone who spent a huge amount of time with these whales that we need to do excellent science and ask what’s going on in their world. But then, importantly, we also need to deliver on that and ask ourselves, ‘Well, what are we going to do about it?’”
Originally published by Cosmos as Talking whale: the quest to decode their secret code
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https://cosmosmagazine.com/nature/talking-whale-the-quest-to-decode-their-secret-code/
