By Dr. Becker
According to a University of St. Andrews press release:
"Bottlenose dolphins are one of the very few species in the animal kingdom that use vocal learning to develop their own vocal signature early in life. Each dolphin produces its own unique signature whistle that describes its individual identity."
And because each whistle is unique, dolphins are able to call to each other by mimicking the whistle of a dolphin they want to communicate with. It’s the equivalent of calling each other by name – though the “names” are abstract.
Mimicking the Signature Whistles of Other Dolphins Is Like Calling Them By Name
Previous studies have shown that dolphins copy signature whistles, but until now, scientists have questioned whether the signals are friendly or aggressive in nature.
A new study published in the Proceedings of the Royal Society B1 indicates that dolphins seem to mimic those they are close to and want to see again. The study was a collaborative effort of the Sarasota Dolphin Research Program, the University of St. Andrews in Scotland, the Woods Hole (Massachusetts) Oceanographic Institute, the Chicago Zoological Society and the Walt Disney World Resort in Florida.
The researchers analyzed acoustic recordings of about 250-300 wild and captive dolphins to pick out matches. They discovered that dolphins familiar with each other for a significant period of time mimic the whistles of others in the group when they are separated.
As Dr. Stephanie King of St. Andrews explained, “Interestingly, signature whistle copying was only found in pairs of animals composed of mothers and their calves or adult males who form long-term alliances with one another.”
The researchers also found that whistle copying was not done by dolphins who just happened to meet up in the wild. In addition, the mimicking doesn’t occur often, giving further credence to the theory that it goes on only among closely associated dolphins.
"The fact that animals are producing whistle copies when they are separated from a close associate supports the idea that dolphins copy another animal's signature whistle when they want to reunite with that specific individual," says Dr. King.
When It Comes to Communication Skills, Dolphins are Closer to Humans Than Any Other Species
The vocal experience of dolphins puts their ability to communicate closer to that of humans than any other species.
According to study authors:
"The bottlenose dolphin signature whistle stands out in that it is invented by its main producer and can only be shared by animals who had experience with the inventor. Besides humans, bottlenose dolphins appear to be the other main example of affiliative copying with such individually specific learned signals."
The researchers also found that dolphins alter their whistle copies ever so slightly to avoid confusion for others who hear them. The dolphins’ copy whistles are produced immediately following the original whistles (a behavior called vocal matching) and are clearly directed toward the owner of the original whistle.
Next on the researchers’ agenda is to play back copies of dolphins’ own signature whistles to them. If they respond, we can conclude copying of signature whistles can potentially be used to communicate with dolphins.