Different species of whales inhabiting Earth’s oceans use different types of vocalizations to communicate. Sperm whales, the largest of the toothed whales, communicate using bursts of clicking sounds – called codas – somewhat resembling Morse code.
A new analysis of years of sperm whale vocalizations in the eastern Caribbean has revealed that their communication system is more sophisticated than previously thought, featuring a complex internal structure filled with a “phonetic alphabet.” Researchers have identified similarities with aspects of other animal communication systems – and even with human language.
Like all marine mammals, sperm whales are very social animals, their cries are an integral part of this. The new study has provided insight into how these whales communicate.
“Research shows that the expressiveness of sperm whale calls is much greater than previously thought,” said Pratyusha Sharma, a doctoral student in robotics and machine learning at the Massachusetts Institute of Technology and lead author of the study published Tuesday. in the journal Nature Communications.
“We don’t know yet what they’re saying. We then study the calls in their behavioral contexts to understand what the sperm whales might be communicating,” Sharma said.
Sperm whales, which can grow to around 18 meters in length, have the largest brains of any animal. They are deep divers that feed on giant squid and other prey.
The researchers are part of the CETI (Cetacean Translation Initiative) project machine learning team. Using traditional statistical analysis and artificial intelligence, they examined calls made by about 60 whales recorded by the Dominica Sperm Whale Project, a research program that has gathered a large dataset on the species.
“Why are they exchanging these codas? What information could they share? » asked study co-author Shane Gero, lead CETI project biologist and founder of the Dominica Sperm Whale Project, also affiliated with Carleton University in Canada.
“I think it’s likely that they use the codas to coordinate as a family, organize babysitting, foraging and defense,” Gero said.
Variations in the number, rhythm and tempo of clicks produced different types of codas, the researchers found. The whales modified, among other things, the duration of the codas and sometimes added an extra click at the end, like a suffix in human language.
“All of these different codas that we see are actually built by combining a relatively simple set of smaller pieces,” said study co-author Jacob Andreas, a professor of computer science at MIT and member of the CETI project.
People combine sounds – often corresponding to letters of the alphabet – to produce words that carry meaning, and then produce sequences of words to create sentences conveying more complex meanings.
For people, Sharma said, “There are two levels of combination. » The lower level is that of sounds and words. The next level up is from words to sentences.
Sperm whales, Sharma said, also use a combination of two-level features to form codas, and the codas are then sequenced together as the whales communicate. The lower level has similarities to the letters of an alphabet, Sharma said.
“Each communication system is adapted to the environment and animal society in which it evolved,” Sharma added.
The communication system used by sperm whales differs from, for example, the “songs” of humpback whales – and, for that matter, the whistles, chirps, croaks and other various vocalizations of various animals.
“Human language is unique in many ways, yes,” Gero said. “But I suspect we will find many of the patterns, structures and aspects considered unique to humans in other species, including whales, as science advances – and perhaps also features and aspects of animal communications which humans do not possess.”
If scientists can decipher the meaning of what sperm whales “say,” should people try to communicate with them?
“I think we need to do a lot more research before we know if it’s a good idea to try to communicate with them, or even have an idea if it will be possible,” Andreas said.
“At the same time, I’m hopeful that we can learn a lot more about what information is actually encoded in the vocalizations that we listen to, what kind of information is in those clicks and those codas, as we begin to understand the behavioral context in which this occurs,” Andreas added.
News Source : www.nbcnews.com
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