Click, click! Scientists decode sperm whales' mysterious phonetic alphabet

Produced by: Science Popularization China

Author: Tian Dawei (popular science creator)

Producer: China Science Expo

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In the science fiction movie "Arrival", a linguist tried to learn the language of aliens and eventually achieved communication with alien civilizations. After mastering the alien language, the protagonist also had the aliens' way of looking at the world, breaking our original concept of time and being able to foresee the future.

Although the content described in science fiction stories is just a romantic fantasy of cross-species communication, language does have an impact on human thinking and the way we view the world. Wittgenstein mentioned in "Tractatus Logico-Philosophicus" that "the limits of my language are the limits of my world." Viorica Marian mentioned in the book "How Language Shapes the Human Mind" that the language a person uses will affect the way a person views the world and the way he thinks about problems.

Mastering another human language is enough to change the way we see the world. If we can master the language of another creature, it may really help humans open up a whole new way of thinking.

In the ocean, scientists have discovered a group of intelligent creatures that may have a language system - whales. A recent ecological research paper published in Nature Communications, an academic journal under Springer Nature, found that sperm whales can combine and adjust different "click" sounds and rhythms to create complex calls similar to human language. Listening to and deciphering their sounds may enable humans to achieve cross-species communication.

Humpback Whale

Image source: wikimedia

Of course, all of this is based on the premise that whales really do have their own language.

CETI: Translation project to understand whale clicks

The songs of whales have long been known to humans. Although many whales have low-frequency calls, fortunately, some of their sounds fall within the human hearing range. In the 1940s, humans captured a large number of whale "songs" through underwater microphones. As more and more whale songs were recorded, people gradually discovered some fixed patterns, and some rhythms would repeat, which made people begin to suspect that "whales may be using songs to convey certain information."

Among singing whales, the songs of sperm whales are definitely not beautiful, but their "click-click" sounds have fascinated some scientists.

sperm whale

Image source: wikimedia

In the ocean, sperm whales make clicking sounds for hunting, but as highly social animals, they use these sounds to communicate between family members or different family groups.

A scientist named David Gruber was deeply attracted by the sound of sperm whales. In 2017, Gruber entered the Radcliffe Institute for Advanced Study at Harvard University, which brings together top scientists from many disciplines and is a good place for scientists to conduct interdisciplinary exchanges and open up research ideas. Gruber's most ambitious plan also started here.

While Gruber was listening to the scent whale sounds in his office, a scientist named Shafi Goldwasser happened to be passing by Gruber's office and heard the sounds as well.

Goldwasser is a computer scientist who won the Turing Award in 2012 for her contributions to cryptography. This award is known as the "Nobel Prize in Computer Science." Goldwasser believes that the sounds made by sperm whales are like Morse code, and that machine learning methods may be used to decipher the rules behind them, so she told Gruber about this idea.

The two scientists hit it off, but they still needed to consult other experts to see if this could be done. Coincidentally, Michael Bronstein was also a researcher at the Harvard Radcliffe Institute for Advanced Study at the time. He is an expert in artificial intelligence and later joined Oxford University in 2022 and was appointed DeepMind Professor of Artificial Intelligence.

Brownstein thought that this idea was crazy, but it was worth a try because AI was good at it. After getting the expert's confirmation, Gruber began to push forward the project. In this way, the whale language translation project, CETI, was born.

The name of the CETI project is deliberately reminiscent of the SETI project (Search for Extraterrestrial Intelligence), which also shows that in Gruber's mind, this is an extremely great project.

The ultimate goal of this project is to understand the language of whales.

CETI Project

Image source: Screenshot of CETI official website

Epilogue: The key to deciphering whale language?

Sperm whales are the animals with the largest brains in nature, and they are also social animals. In addition to hunting every day, sperm whale groups also have specific times to communicate and interact with each other using a sound called codas.

"Codas" is originally a musical term, which refers to the regular, repetitive sounds that appear at the end of some music, which are called "codas". These sounds often have special meanings. The clicks made by sperm whales also have such sounds, so they are also called codas.

Although the name is coda, it does not mean that these sounds must appear at the end of the sperm whale's call. In the CETI study, scientists analyzed the sounds of sperm whales in the eastern Caribbean from 2005 to 2018.

Two sperm whales communicating

Image source: Reference 5

The results showed that sperm whales use codas alternately when communicating, as if they are asking and answering questions, and that their use of codas may be more complicated than people think. First, when sperm whales use clicks, they may speed up or slow down the sound, which is called "rubato" in the study, similar to telescoping. In humans, it is like some people speak fast, some speak slowly, or change the speed of speech in certain situations.

In addition, sperm whales may add some additional clicks as modifications on the basis of fixed patterns. Scientists have also found similar phenomena in the study of the language of other whales. For example, Brenda Mccowan, a professor at the School of Veterinary Medicine at the University of California, Davis, also found that there are codas and modifications in the songs of humpback whales when she studied the songs of humpback whales, but it is still unclear what the modified sounds of humpback whales are used for. Of course, among these sounds, scientists are most concerned about the codas of whales.

'Alphabet': The first step to understanding whales

The sperm whale's wake is generally composed of 3 to 40 rhythmic clicks. There are two dimensions involved here: the rhythm and the sound used each time the rhythm is struck.

To make it easier to understand, we use the situation in the human world as an analogy. Rhythm is easy to understand. "Da-da-da-da-da" and "Da-da-da-da-da-da" are two different rhythms. The sounds used when beating the rhythm can also be replaced. It can be "Da-da-da-da", "Ka-da-da-da", or "Ka-ka-ka-ka-ka". With different rhythms and sound combinations, sperm whales can convey a lot of information.

After using AI to analyze sperm whale tail sounds, researchers identified 156 types of sperm whale tail sounds and compiled a sperm whale tail sound "alphabet" based on these tail sounds, which includes 18 common rhythms used by sperm whales and different types of sounds used in each beat. These may be the basic elements of sperm whale language, just like the Chinese phonetic alphabet we use.

Sperm whale alphabet

Image source: Reference 5

The study concluded that the "alphabet" only summarizes the possible basic elements in the sperm whale's tail sound and does not represent any meaning. If the sperm whale's click sound is really the same as human language, then scientists sorting out the "alphabet" is just the first step.

Next, the researchers looked at possible meanings based on the combinations in the alphabet.

For example, playing certain specific sound combinations to sperm whales to see how they react and indirectly infer their meaning.

Diana Reiss, a psychologist and animal behaviorist at the City University of New York, believes that although it is difficult for humans to translate sperm whale language into human language one-to-one, it is already remarkable to be able to do so.

In addition, some scientists believe that such an alphabet may be meaningless. For example, we assume that sperm whales will change the speed of some rhythms and add some decorations to the ending, so as to obtain such an alphabet. If the previous assumptions are not true, then this alphabet will be meaningless.

But in any case, this is an important step in our attempt to understand another biological language. If we can decipher the language of whales, we will be able to do more than just talk to whales in the future, but also see the world from a completely new perspective. Such thinking may bring unimaginable inspiration to humans.

References:

【1】Sun Zifa. Latest research: Sperm whales can create complex calls similar to human language.[EB/OL](2024-05-08)[2024-05-20].

【2】Whitehead, H. Sperm whales: social evolution in the ocean. Choice 41, 41–3452–41–3452 (2004).

【3】Elizabeth Kolbert, can we talk to whales?[EB/OL](2023-09-04)[2024-05-20]

【4】Whitehead, H. (2003). Sperm Whales: Social Evolution in the Ocean. Chicago: University of Chicago Press. p. 4. ISBN 978-0-226-89518-5.

【5】Sharma P, Gero S, Payne R, et al. Contextual and combinatorial structure in sperm whale vocalisations[J]. Nature Communications, 2024, 15(1): 3617.

【6】Mindy Weisberger. Scientists say they've discovered a 'phonetic alphabet' in whale calls.[EB/OL](2024-05-13)[2024-05-20]

【7】Sarah Kuta.Scientists Discover a 'Phonetic Alphabet' Used by Sperm Whales, Moving One Step Closer to Decoding Their Chatter. [EB/OL](2024-05-8)[2024-05-20]