The Amazon Pink Dolphin’s Voice: Dolphins at sea greet each other

DOLPHINS AT SEA GREET EACH OTHER

When groups of dolphins meet up in the open sea they thoughtfully introduce themselves.

Bottlenose dolphins swap signature whistles with each other when they meet in the open sea, a new study reports, suggesting that these marine mammals engage in something akin to a human conversation.

Earlier research found that signature whistles are unique for each dolphin, with the marine mammals essentially naming themselves and communicating other basic information.

A signature dolphin whistle in human speak, might be comparable to, “Hi, I’m George, a large, three-year-old dolphin in good health who means you no harm.”

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The latest study, published in the Proceedings of the Royal Society B, is the first to show how free-ranging dolphins in the wild use these whistles at sea. The findings add to the growing body of evidence that dolphins possess one of the most sophisticated communication systems in the animal kingdom, perhaps even surpassing that of humans.

“In my mind, the term ‘language’ describes the human communication system; it is specific to us,” co-author Vincent Janik of the University of St. Andrews Sea Mammal Research Unit, told Discovery News. “It is more fruitful to ask whether there are communication systems with similar complexity. I think the dolphin system is probably as complex as it gets among animals.”

Janik and colleague Nicola Quick studied how bottlenose dolphins in St. Andrews Bay, off the coast of northeast Scotland, communicate with each other. While in a small, quiet boat, the researchers followed the wild dolphins and recorded their vocalizations.

Analysis of the observations and recordings found that the dolphins usually swam together in a group moving slowly and relatively quietly.

“When another group approaches, usually one or more animals start to produce their signature whistles,” Janik said. “We then hear dolphins from the other group calling back with their own signatures, and after or during this counter-calling the animals get together as one group and continue swimming together. Shortly after the union of the groups, they become much more quiet again.”

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Most animals have some sort of communication system that allows them to make similar introductions and meetings, but dolphins are unique in that they can invent and copy new sounds. This is “unlike non-human primates, who are stuck with their species-specific repertoire,” he said.

The researchers also noticed that usually just one dolphin from each group would emit a signature whistle before the other group members would join the second group. This might mean that dolphins elect a “spokesman” to represent the entire group during meetings. Such an individual may be an older dolphin, Janik said, but he thinks the other dolphins are not fully silent, and may be using echolocation instead of whistles.

“We don’t know whether echolocation works in this way, but it seems like a viable hypothesis,” he said. “In that case, the whistle exchange is more of a greeting ceremony that communicates a friendly intention and is perhaps not needed to identify the group after the first introduction.”

Dolphins at a distance may rely more upon sounds and echolocation for their communications than visual, scent and other signals. This is likely due to their marine environment and social structure. A dolphin can hear the whistle of another dolphin over a distance of about six miles and with lots of noise in the background.

Heidi Harley, a bottlenose dolphin expert who is a professor of psychology at the New College of Florida, told Discovery News that she believes the findings are key to understanding how dolphins use signature whistles.

“Now we know that dolphins in groups use signature whistles before they join each other,” Harley said. “This is an important piece in the puzzle that we’ve been constructing about signature whistles.”

She added, “I was surprised to learn that the exchanges appeared to be between only a single individual in each group.”

Source: Discovery News

How Dolphins Say Hello

By Elizabeth Norton, ScienceNOW

Bottlenose dolphins have a knack for language. They can understand both the meaning and the order of words conveyed through human hand gestures—correctly putting an item on the right side of their tank into a basket on the left, for example. Now humans, too, are beginning to understand dolphin language as more than just a cacophony of clicks, pulses, and whistles. A new study shows that dolphins use their own unique calls, known as signature whistles, to introduce themselves to others when meeting at sea.

Until recently, researchers could study signature whistles only in captive animals—raising the question of whether the whistle developed in response to capture, isolation, or stress. A 2004 study showed that a group of free-swimming bottlenose dolphins in Florida did indeed use signature whistles. But information about how they used these sounds was scant.

Marine biologists Vincent Janik and Nicola Quick of the Sea Mammal Research Unit at the University of St. Andrews in the United Kingdom were focusing on signature whistles as a way of understanding how dolphins communicate in the natural world. “Dolphins are comparable to great apes in their cognitive skills, but all we know is what they do in a lab,” Janik explains. “We wanted to understand how dolphins use their intelligence outside of the tasks that humans set for them.”

To learn more, Quick and Janik followed a group of bottlenose dolphins that swim long distances around the eastern coast of Scotland. The researchers used a small boat to tow an array of underwater microphones, called hydrophones, about 2 meters below the surface and recorded the sounds of individual dolphins identified by their dorsal fins. The animals were matched with their calls by their surfacing locations and swim speed, as well as by digital cameras while they were near the surface.

The dolphins used signature whistles when meeting up with another group, Quick and Janik report online today in the Proceedings of the Royal Society B. What’s more, they gave the distinctive whistle only if they actually mingled with the other dolphins. Of 11 “conversations,” only two did not result in the groups’ joining together, and only once did the groups join up without first exchanging whistles.

Even more intriguing was that only one member of each group gave the signature whistle. According to Janik, there could be several explanations. The group could have a leader doing the “talking;” the dolphins may have identified each other using echolocation (the clicks the dolphins send out that echo back from nearby objects), and the whistle was more of a ritual; or the groups may have been together previously and already known each other.

Both the methods and the findings are the first of their kind, according to Laela Sayigh, a cetacean biologist at the Woods Hole Oceanographic Institution in Massachusetts. (Sayigh, who co-authored the 2004 study of Florida dolphins, has collaborated with Janik in the past but was not involved in the current research.) Understanding how dolphins use signature whistles opens up many exciting research possibilities, according to Sayigh. “We know dolphins learn to copy each other’s signature whistles. What if they use a signature whistle to refer to a ‘third party’ or a dolphin that isn’t there?”

The study also sheds some light on dolphin society, says Heidi Harley, a comparative cognitive psychologist at the New College of Florida in Sarasota. “Dolphins live in groups that come together and break up, often ending up composed of different individuals,” she says. “Exchanging signature whistles may be one way they manage these interactions.”

This story provided by ScienceNOW, the daily online news service of the journal Science.

Source: Wired

Dolphins make unique whistles to say ‘hello’

 Dolphins make unique whistles to say `hello`Washington: Dolphins are well known for their playful and gregarious nature. Now, a new study has found that these mammals use specific melodies called signature whistles to introduce themselves when they meet new groups.

These melodious exchanges are the key part of a greeting sequence that allows dolphins to recognise each other in the wild, researchers said.

“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’,” study researcher Vincent Janik, an expert in animal communication at the University of St Andrews in Scotland, said.

Signature whistles of dolphins were first discovered in the 1960s, but new research is the first to reveal how these sea mammals use the sounds when one pod meets another in the ocean, LiveScience reported.

For their study, published in the journal Proceedings of the Royal Society B, Janik and his colleagues used special arrays of underwater microphones to follow bottlenose dolphin pods in St Andrews Bay as they swam around and interacted with other groups of dolphins.

They used a statistical method to tease out patterns in signature whistles (those whistles that dolphins develop as their personalised calling card) and differentiate those noises from the other chirps and squeaks dolphins produce

In cases where dolphin pods joined and swam together, the team found, such meetings were preceded by one dolphin in the group producing a signature whistle and another dolphin in the second group answering.

When dolphin groups swam by one another and didn’t join, these meet-and-greet whistles were absent, the team found.The “greeting ritual” may not require every group member to introduce themselves, because dolphins can use echolocation to determine the size of the other group, Janik said.The researchers, however, weren’t able to pinpoint which dolphin individuals made the signature whistles, so they don’t know if each dolphin pod has a designated social chairman or if any dolphin can pipe up and propose a get-together.

It’s likely that there is no designated leader as dolphin groups tend to be fluid and lack a stable commander-in-chief, Janik said.

According to the researchers, the dolphin calls are very important as they are one of the few animals that makeup new sounds.

Social primates know each other from the sounds of their voices, but they don’t create signature identification calls.

Dolphins, on the other hand, start developing their own whistles at just a few months of age. They’re also verbally adept, capable of mimicking the songs of other animals and even using particular sounds to refer to specific objects in captivity, almost as if they’re using words.

“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.”

Source: Zeenews

SELVA Vida Sin Fronteras acknowledges Kevin Schafer’s important contribution towards protecting the highly endangered Amazon pink fresh water dolphin. Title photographs of our “The Amazon Pink Dolphin’s Voice” were taken by Mr. Schafer. 

Editorial: Selvavidasinfronteras.org

Selvavidasinfronteras.wordpress.com

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~ by FSVSF Admin on 1 March, 2012.

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