Scientists recently revealed a communication pattern in whale songs.
- May 10, 2024
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The attempt to translate whale songs into human language began about sixty years ago, when whale melodies were discovered. Are the animals expressing themselves in intricate ways similar to how humans would? or, like dancing bees, exchanging smaller, more basic bits of knowledge? Or are they conveying a message that we are not yet aware of?
A group of computer scientists and marine biologists collaborated in 2020 to examine the click-clacking vocalisations of sperm whales, which are grey, block-shaped leviathans that inhabit the majority of the world's oceans. Scientists revealed on Tuesday that whales employ a far more varied range of noises than was previously thought, which they dubbed a "sperm whale phonetic alphabet."
Humans also possess a phonetic alphabet, which we employ to create an almost limitless number of words. The author of the study, Shane Gero, a marine biologist at Carleton University in Ottawa, said it's uncertain if sperm whales use comparable phonetic sounds to form a language.
Dr. Gero claims that the underlying parallels that we do discover are quite intriguing. It has fundamentally changed how we must carry out our work going forward.
Dr. Gero and his associates have been tracking a group of 400 sperm whales in the eastern Caribbean island country of Dominica since 2005. They have been using underwater microphones to record the whales' conversations, and they have fitted some of the animals with sensors.
The haunting songs made popular by humpback whales in the 1960s are not produced by sperm whales. Rather, they produce a cacophonous sound that resembles a combination of a creaking door and Morse code. Codas are the short pulses, usually lasting three to forty clicks, that sperm whales make. It's possible that they are speaking to one another because they typically sing these codas while swimming together.
Dr. Gero and his associates have examined thousands of hours' worth of recordings of the underwater noise throughout the years. As it happens, there are many kinds of codas found in sperm whales.
For instance, one variety known as "1+1+3" consists of two clicks followed by a pause, then three clicks quickly one after the other.
Dr. Gero and his associates launched "Project CETI," or "Cetacean Translation Initiative," with financial support from philanthropists to explore the possibility of using artificial intelligence and other computer advancements to decode whale music. (Whales are also known as cetaceans; the name is a pun on SETI, the well-known search for extraterrestrial life.)
Pratyusha Sharma, an M.I.T. graduate student studying computer science, reexamined the Dominican Republic data as part of the research. However, she found it frustrating how biologists represented it.
The codas appeared as a succession of dots along a horizontal line on a computer screen, with each dot denoting a click. Comparing codas proved to be difficult for Ms. Sharma, particularly in situations where multiple whales were singing simultaneously. Rather, she plotted the clicks for each coda as dots on a vertical line and then arranged the codas according to when they started on a horizontal line.
Ms. Sharma noticed something different with the new layout. Sperm whales occasionally lengthen the interval between clicks during a coda repetition before progressively tightening it. This phenomenon was dubbed "rubato" by Ms. Sharma and her colleagues, which is a musical term for accelerating and decelerating tempo.
When Ms. Sharma noticed something in sperm whale songs that Dr. Gero and his colleagues had been missing for years, he was taken aback. He stated, "It was a way we hadn't looked at it."
The human ear can overlook a rubato because codas move so quickly. However, thousands of recorded codas revealed the pattern to the researchers.
Rubato, according to the experts, is crucial to whale communication. It was discovered that when a nearby whale employed rubato, the other whales would quickly match the tempo shift with their own codas.
Sperm whales have a behaviour known as ornamentation whereby they periodically add an extra click to the end of the coda, as seen by Ms. Sharma's new visualisations. The extra clicks were more than just decorative flourishes, as the investigators discovered. Leading whales frequently displayed ornamentation, to which their followers frequently returned with their own codas.
The examination revealed that the traditional catalogue of sperm whale codas was unable to fully represent their intricacy. For example, sperm whales can create a 1+1+3 coda that lasts 0.25, 0.75, or four-fifths of a second. Some codas might only be half a second or a third of a second long.
In total, 156 separate codas were identified by the researchers, each with a unique arrangement of pace, rhythm, rubato, and ornamentation. This variance, according to Dr. Gero, is remarkably comparable to how humans mix movements of our tongue and lips to form a range of phonetic sounds.
On its own, a sound like "ba" or "na" has no semantic significance. However, we can blend them to form significant words like "banana." The researchers hypothesised that sperm whales may similarly mix the characteristics of codas to convey meaning.
The whale alphabet was hailed as an interesting advancement by other scientists. However, they suggested that sperm whale codas might resemble music rather than language.
"Emotions can be strongly influenced by music without it actually conveying information," according to Oregon State University bioacoustician Taylor Hersh. By synchronising their songs, she surmised that rubato might be one way sperm whales strengthen their social relationships.
The alphabet is enabling the researchers to delve deeper into whale songs, according to Jacob Andreas, an author of the study and computer scientist at the Massachusetts Institute of Technology. Now that we have the necessary resources, we can start pursuing the much more ambitious long-term goal of Project CETI, which is to try and figure out what all of this actually means.
Ocean noises are being recorded by microphones placed around the Caribbean 24 hours a day, and researchers are teaching computers to distinguish sperm whale choruses from background noise.
AI applications akin to ChatGPT are also being trained by Dr. Andreas and his associates. These models may pick up on details that experts have overlooked in addition to rubato and ornamentation after hearing the sperm whale songs.
The idea is that eventually computers will be able to create original whale tunes that can be performed for the whales.
Other experts are sceptical about such endeavors. Marine biologist Luke Rendell of the University of St Andrews in Scotland is concerned that the artificial intelligence models treat whale sounds more like music than as a language.
"I have no doubt that you could develop a language model that could learn to produce sequences that resemble those of sperm whales," said Dr. Rendell. But that's all you get.