Seven ancient “tribes” of sperm whales live in the vast Pacific Ocean, proclaiming their cultural identity with distinctive click patterns in their songs, according to a new study.
It is the first time that cultural markers have been observed between whales and mimic markers of cultural identity between human groups, such as distinctive dialects or tattoos.
The discovery is also a step towards a scientific understanding of what whales say to each other in their underwater songs – something that remains a mystery despite years of research.
Bioacoustician Taylor Hersh, a postdoctoral researcher at the Max Planck Institute for Psycholinguistics in Nijmegen, Netherlands, and lead author of the study published this month in the Proceedings of the National Academy of Sciences, said that sperm whales often exchange streams of loud clicks with each other when they rest in close proximity. to the surface between dives into deeper water — sometimes more than a mile down — for prey such as squid and fish.
Streams of clicks are divided into what are called “codas,” and the calls are known as sperm whale “songs” — though they’re not very musical and can sound a bit like hammering and screeching (Navy sonar operators used to call the sperm whales “carpenter fish” for this reason).
No one knows what all sperm whale codas mean, but they may have distinctive rhythms and tempos known as “dialects,” Hersh said. And the new study shows that they include specific patterns — bursts of clicks that last only a few seconds, like bits of Morse code — that whales use as “identity codes” to proclaim their membership in a particular tribe.
“Identity codes are really unique to different whale cultural groups,” he said.
The study also shows that sperm whales accentuate their dialects when rival tribes are close by—an indicative behavior also seen among humans—so that whales from different tribes usually do not interact with each other when they occupy the same waters. he said.
The study analyzed more than 40 years of underwater recordings of sperm whale calls made at 23 locations in the Pacific Ocean, from Canada to New Zealand and Japan to South America. From these, the researchers extracted more than 23,000 click patterns and then used an artificial intelligence system to determine which of these were distinctive ID codes.
Now they have found that there are at least seven distinct “vocal tribes” of whales across the Pacific Ocean, each with their own identity codes, Hers said.
Each clan could consist of thousands of individual sperm whales, and calls from members of the same clan have been recorded at the ends of the Pacific Ocean, sometimes more than 9,000 miles apart. It is not known how many sperm whales exist in the world’s oceans, but it is estimated that there may be as few as 360,000. about half of them could live in the Pacific.
And whale tribes can be thousands of years old. Hersh said mother and daughter sperm whales always share the same vocal line. Males, however, often travel between groups and can be more fluid in their clan membership.
Since sperm whales live for about 70 to 90 years, the ages of a grandmother and her granddaughter can span about 150 years. “So the tribes certainly seem to be hundreds of years old, and maybe much longer,” he said.
Sperm whales spend most of their lives away from humans and in a very different environment – deep ocean diving – so little is known about their behaviour. Although researchers can’t yet say how the identity codes in whale songs reflect other distinctive aspects of their tribe’s culture, there is evidence that different tribes use different techniques to hunt prey, Hersh said.
Gašper Beguš, an assistant professor of linguistics at the University of California, Berkeley who was not involved in the study, likens sperm whale vocal tribes to dialect groups among humans.
A well-known linguistic study several decades ago found that islanders on Martha’s Vineyard were more likely to emphasize their distinctive island dialect when speaking among non-islanders, he said.
Similarly, researchers in the most recent study found that sperm whales were more likely to emphasize their clan’s click dialects in areas where they were more likely to encounter members of other clans, he said.
Beguš is part of Project CETI – the Cetacean Translation Initiative – established last year to decipher the sounds of sperm whales. The project will combine language studies and machine learning to understand what sperm whales say to each other and perhaps enable interspecies communication.
“We are starting to collect data with microphones on whales in the water as well,” he said. “We follow their behavior and learn a lot about their environment and social structure.”
While it was previously known that whales exchange information in codas, this is the first time the identity codes of whale tribes have been determined — a finding that will be critical to deciphering their entire songs, he said.
Dolphin and whale scientist Janet Mann, a professor of biology and psychology at Georgetown University, who was also not involved in the latest study, agreed that the research could help better understand whale speech.
“As the authors note, we still understand very little about the function of sperm whale codes,” he said in an email. “This is an important step in determining not only the function and significance of codas, but also the forces shaping cultural evolution in animals.”
This article was originally published on NBCNews.com