What does a dolphin say when it crosses oceanic paths with other dolphins? Hello, of course, followed by a formal introduction that’s relayed through a high-pitched “signature whistle.”
Marine biologists from the University of St. Andrews in Scotland have long been studying dolphins’ cacophonous communication style — including a series of clicks, pulses and whistles — while the animals are in captivity. But until recently, they questioned how the signature whistles were used in the wild.
Now, they have an answer. The researchers used underwater microphones to follow pods of bottlenose dolphins in St. Andrews Bay. After weeding out some of the other sounds the animals make, they were able to determine that dolphins use their “signature whistles” when meeting up with other pods of dolphins — much like a catchphrase. Think, “Hey, how’s it going?” but in whistle form.
“It’s not just ‘I’m so-and-so,’ but the other information also in that whistle is, ‘I’m so-and-so, and I’m interested in making contact in a friendly way, I’m not attacking,’” Vincent Janik, one of the study’s researchers, told LiveScience.
In cases where the pods joined up to swim (and in our minds, splash, laugh and play) together, one dolphin from the first group emit its whistle, which was then returned by a dolphin from the second group. When pods did not join together, no whistles were exchanged.
Because dolphins’ pods are known to fluctuate, the researchers are unsure of whether the ones who send the invitational whistles are group leaders or just interested in being social. They also note that the animals could already be acquainted. Either way, the calls are an important glimpse into the species’ complex communication style.
“What I found really rewarding is to be out there and see how they communicate amongst themselves,” Janik said. “These are wild groups that are just doing whatever they’re doing. It’s really the first time that we can pinpoint down two individual groups and how they interact in a vocal domain, which is really cool.”