Dolphins Whistle Their Names with Complex, Expressive Patterns

Dolphins Whistle Their Names with Complex, Expressive Patterns

Dolphins “signature whistles” are one of the most complex forms ever studied of animal communication. They use similar names to identify themselves and communicate personal information to others. New research shows how these calls can differ between individuals and situations.

Experts can identify a dolphin’s signature sound by listening to it call out to its . peers . These animals vary their whistles in many ways. They repeat sections in loops, alter the pitch, add and delete short segments, and they also change the pitch. A new study, published in Frontiers in Marine Science, evaluates these changes through a database of nearly 1,000 recording sessions that collected whistles from around 300 individual dolphins over four decades. *

To calculate the signature whistles’ variability and allow comparison with sounds from other species (particularly birds), the authors used a statistical metric that evaluates 21 different facets of a sound–such as length, frequency, pitch and pattern. The higher the species score, the more varied each individual’s calls are. The largest audio palette of identification sounds in a recently published comparison paper , was recorded by bottlenose dolphins. Larks’ were next, but researchers are still unsure how humans compare.

This metric is useful for comparing species, according to Laela Sayigh, a Woods Hole Oceanographic Institution marine biologist and the lead author of the dolphin study. But she notes that the 21 facets barely scratch the surface of dolphin whistles’ true complexity. “It’s actually kind of phenomenal,” Sayigh says, that even using this “coarse” metric, “dolphins are the most individually distinctive communicators.”

University of South Bohemia behavioral ecoologist Pavel Linhart, who wasn’t involved in the study but was the one who led the interspecies comparision, said he is glad that the researchers have accounted for this variability. He adds that “it was so obvious that it was so easy to identify [individuals],” and that the researchers didn’t quantify it previously.

Scientists are just beginning their investigation into the reasons dolphins use to change their signature whistles. This could be to express emotions, for one. Sayigh states that future work will help to decipher the nonsignature whistles dolphins also exchange. “We are still in the infancy stages of understanding those .”

*Editor’s Note (10/20/22): This sentence was edited after posting to correct the description of 1,000 whistle recording sessions.

This article was originally published with the title “Name Check” in Scientific American 327, 5, 25 (November 2022)

doi: 10. 1038/scientificamerican1122-25

ABOUT THE AUTHOR(S)

    Rebecca Dzombak is a freelance science writer who covers Earth sciences and the world in the Anthropocene.

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