What do sperm whales say? Researchers find a complex ‘alphabet’

Sperm whales have a lot to say. The animals spend much of their lives in the dark, searching for giant squid in the depths of the ocean. So sound rules their world, especially in their close-knit family groups where they can be downright talkative.

Sperm whales do not sing in the melodious way that humpback whales are known for. Instead, they click in long conversations that sound like a mix of Morse code and popping popcorn. For decades, scientists have recorded their conversations in hopes of unraveling their patterns.

Now, a new study shows that sperm whales have a much more nuanced communication system than previously thought. Using machine learning, researchers at the Massachusetts Institute of Technology and a partnership called Project CETI have identified a larger lexicon of sound patterns, like an “alphabet,” which they say could potentially be combined in ways that convey meaning, like a language does that.

“Our results show that there is much more complexity than previously thought and this challenges the current state of the art or understandings of the animal world,” said Daniela Rus, director of the MIT Computer Science and Artificial Intelligence Laboratory.

Scientists have long debated whether animals have language, with some maintaining that humans are the only species capable of its complexity. The question is whether new technologies such as artificial intelligence can unravel the mysteries of animal communication that humans have missed so far.

“Some of what they do may be completely different from the way we communicate, and we may never fully understand those differences,” says Taylor Hersh, a postdoctoral researcher at Oregon State University’s Marine Mammal Institute.

Family conversations about sperm whales

From grandmothers to granddaughters, sperm whale families often dive together, hunt together and even babysit each other’s young. Biologist Shane Gero has spent years with these whales as part of the Dominica Sperm Whale Project and says these exchanges sometimes seem very familiar.

“It’s hard not to see cousins ​​playing while chatting,” says Gero, who also works on Project CETI. “To not see mothers surrender to a babysitter and exchange a few words before walking out the door, so to speak, to go to dinner in the deep ocean.”

Their vocal exchanges can last an hour, with several whales clicking and repeating in succession. “It is not rude in sperm whale society to talk and overlap at the same time,” says Gero.

Their communication can be broken down into repetitive patterns called codas. A common click for Caribbean sperm whales is the “1+1+3”, where the first two clicks are followed by three faster clicks. Family groups can have dozens of codas, all with different clicks and tempos.

Even a few minutes of recordings of sperm whales can take researchers hours to catalogue. That’s why Gero teamed up with artificial intelligence researchers to create Project CETI, in hopes of deciphering what sperm whales say. They analyzed more than 9,000 recordings of Caribbean sperm whales using advanced computer algorithms.

“By using machine learning to detect the clicks, we discovered that there were so many more clicks than people could manually segment from the dataset,” says Rus, who worked on the project.

The team discovered that sperm whales have a large repertoire of clicks, which they have cataloged in a sperm whale ‘phonetic alphabet’. Sometimes they vary the pace of the clicks in a coda slightly. Sometimes the length of the coda is subtly longer or shorter. Sometimes the whales provide an extra click. These variations can be closely coordinated because different whales communicate with each other. The patterns also appear to be based on the context of conservation.

“They can be predicted by machine learning in the same way that you could predict the order of syllables or the order of words in a sentence,” says Rus. “It really turned out that communication with sperm whales was indeed not random or simplistic, but rather structured.”

The researchers say this shows that sperm whales may have the means to make different combinations of codas, something considered an ingredient of language. People can recombine many meaningless bits of language – such as sounds and syllables – and make something meaningful out of them.

So what do sperm whales say?

Determining what sperm whales mean by different codas or combinations of codas is a much more difficult task. As part of the research, Project CETI is collecting more recordings of whales and trying to link them to behavior and actions. But knowing which contexts are important and what matters to the whales is a challenge.

“If we were to just study North American English-speaking society in the dental office, we would walk away with the fact that the most important part of their communication system is the word ‘root canal,’” says Gero. “We might just be wrong because we didn’t have a comprehensive picture.”

Many of the linguistic ways that humans define language may also not apply to sperm whales, which have been communicating in the oceans for much longer than humans.

“I think it’s valuable to see whether patterns in animal communication match patterns in human language,” says Hersh. “But I think it’s important to remember that just because we don’t find evidence for something doesn’t mean the system isn’t complex in ways we don’t understand.”

Sperm whales are still recovering after being decimated by commercial whaling, and are facing newer threats such as ship attacks and plastic pollution. Gero says looking for similarities with humans is helpful because humans have so much influence on the whales’ environment.

“Finding the fundamental underlying similarities is important,” says Gero. “If we can talk about whales and how important their grandmothers are, or how important it is to be a good neighbor, or the importance of cultural diversity in society, then that really resonates with people and can create a change in trigger human behavior to protect the whales.”

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