Researchers Unveil a New 'Vocal Code' in Dolphin Communication
Researchers harnessing advanced technology reveal that dolphins exhibit diverse patterns in their vocalizations, suggesting a sophisticated form of communication beyond previous understanding.
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Scientists have made a remarkable breakthrough in understanding whale communication. By using artificial intelligence to analyze thousands of recorded sequences of sperm whale clicks, they have uncovered previously unknown complexity in how these majestic creatures communicate.
Whales create a diverse acoustic tapestry through variations in tempo, rhythm, and length of their click sequences, known as codas. This suggests that whales have the ability to combine click patterns in different ways, mixing and matching phrases to communicate a wide range of information to each other.
The meaning behind sperm whales' clicks remains a mystery to humans. However, understanding the extent of whales' vocal interactions is a crucial first step in linking their calls to specific messages or social behaviors, as reported by scientists in the journal Nature Communications on May 7.
Study coauthor Dr. Daniela Rus, director of the Computer Science and Artificial Intelligence Laboratory (CSAIL) at MIT, mentioned that this research builds upon previous studies that focused on deciphering the calls of sperm whales. However, this particular study is the first to explore sperm whale calls within the broader context of communication and interactions between whales, leading to some groundbreaking discoveries.
According to Rus, delving into the ability of sperm whales to manipulate and alter different aspects of their codas provides valuable insights into how they convey information through their vocalizations.
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But Dr. Luke Rendell, a researcher at the University of St. Andrews in the United Kingdom, who studies communication in marine mammals, disagrees. He believes that the term "phonetic alphabet" used in the team's findings is misleading. According to him, it does not accurately represent whales' vocal interactions. Rendell expressed his views in an email, clarifying that the term is not a true reflection of the situation.
He mentioned that the use of tempo variation is distinct from how we use alphabet elements to form language. Comparing the two is not supported by evidence and is not very helpful. This comparison limits the perspective to whether it is similar to human language or not, when there are many other interpretations possible.
Pattern recognition
Sperm whales make loud clicks by pushing air through a special organ in their heads called the spermaceti. These clicks can reach 230 decibels, which is even louder than a rocket launch and can potentially burst human eardrums. This was reported by another team of scientists in the journal Scientific Reports.
In a recent study, researchers used machine learning to analyze audio data from The Dominica Sperm Whale Project. This project collects information about sperm whales living in the Caribbean Sea. The recordings included the sounds of around 60 sperm whales from a group known as the Eastern Caribbean clan. These vocalizations were captured between 2005 and 2018.
Previous studies found that sperm whales globally have 150 different types of codas, however, Caribbean whales only utilize 21 of them.
A group of scientists analyzed 8,719 coda sequences to study the timing and frequency. These sequences were observed in various situations such as solitary whale vocalizations, choruses, and interactions between whales. Through the use of artificial intelligence, new coda patterns that were previously unknown were discovered.
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In a study, researchers identified four key elements in dolphin communication: rhythm, tempo, rubato, and ornamentation. Rhythm refers to the pattern of time between clicks. Tempo is the overall length of the communication sequence. Rubato involves variations in timing between consecutive communication sequences. Ornamentation includes an additional click at the end of a series of shorter communication sequences.
Rus mentioned that during vocal exchanges between whales, ornament clicks tend to happen more at the start and end of turns, acting like discourse markers.
Rendell found the ability of whales to synchronize changes in coda tempo to be a fascinating observation.
He expressed his doubts about the 'ornamentation,' mentioning that it is rare and more evidence is needed to confirm that they are not just production errors or filler sounds like 'um' or 'err.'
The program identified 18 types of rhythm, five types of tempo, three types of rubato, and two types of ornamentation in total. Researchers found that these coda features could be combined to create a vast range of phrases. Additionally, the placement of a coda within an exchange or chorus involving multiple whales could further alter the meaning.
Dr. Brenda McCowan, a professor at the University of California Davis School of Veterinary Medicine, expressed excitement about the possibilities of interactive experimentation. She mentioned that many people have eagerly awaited the advancement of technology to enable such innovative activities for years.
In 2021, McCowan was part of a team that interacted with a humpback whale near Alaska. The scientists played a recording of a humpback song from their boat, and for about 20 minutes, the curious whale responded to it.
McCowan, who was not involved in the research, described the experience as an opportunistic experiment. The whale engaged with them both behaviorally and vocally, completely on her own terms.
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Such hands-on experiments with whales and watching how they behave could help us understand the patterns of sperm whale clicks, the researchers explained.
Additionally, the machine learning technique they used could be valuable for analyzing different animal sounds, according to McCowan.
McCowan mentioned that tempo, rhythm, rubato, and ornamentation can be observed in other species of whales. It is already known that humpback whales exhibit these characteristics in their songs. Additionally, there is evidence of similar patterns in other aquatic, terrestrial, and arboreal species that could benefit from this approach.
However, Rendell warned that while this technique is useful for identifying specific communication aspects, it should not be seen as a definitive solution like the Rosetta Stone.
"Machine learning is excellent at identifying patterns in extensive sets of data," noted the speaker, "although it does not generate meaning."
Mindy Weisberger, a science writer and media producer, has contributed to various publications such as Live Science, Scientific American, and How It Works magazine.
Editor's P/S:
The article delves into the groundbreaking research on sperm whale communication, revealing the complexity and diversity of their vocal interactions. Using artificial intelligence, scientists have uncovered previously unknown patterns in whale clicks, suggesting that these majestic creatures possess a remarkable ability to combine and manipulate different elements of their vocalizations to convey a wide range of information. This discovery has sparked excitement among researchers and opens up new avenues for exploring the intricate social dynamics and communication systems of whales.
The article also highlights the ongoing debate among scientists regarding the use of the term "phonetic alphabet" to describe whale clicks. While some researchers believe this comparison to human language oversimplifies the whales' vocal interactions, others argue that it provides a useful framework for understanding their communication patterns. This debate underscores the challenges of interpreting animal communication and the need for further research to unravel the mysteries of these enigmatic creatures.
