Scientists decode dolphin-speak
AAP / 19 December 2007
Humans have taken a major step forward in unlocking the mysteries of dolphin-speak, and found their communication is more complicated than originally thought. A researcher who spent three years listening to bottlenose dolphins living off the coast of Byron Bay, NSW, has found certain whistles are linked to specific behaviour. PhD candidate Liz Hawkins from Southern Cross University’s Whale Research Centre in Lismore listened in to more than 50 different pods of dolphins. Using the starting and final frequency of the sound and its duration, she distinguished 186 distinct whistle types among the 1650 recorded, of which 20 were heard frequently and common to more than one pod.
Ms Hawkins also grouped the whistles into five classes based on tone, and found they were related to certain behaviour. While socialising, dolphins made almost exclusively flat-toned or rising-toned whistles. Travelling pods made mostly “sine” whistles, which rise and fall in bell curves, which Ms Hawkins suggested could be advertising their pod to other pods. “They could be talking to another pod and saying `we are over here. . . do you want to join?’,” she told AAP. Resting was associated with “concave” whistles, sounds that went down in pitch and back up again, while downward toned whistles were not found to be associated with any particular behaviour. One particular whistle was associated with feeding. “They could be advertising they have found food, they could be advertising to other animals there is food there, or it could be referred to a particular type of feeding or a particular type of food,” Ms Hawkins suggested. And Ms Hawkins noticed that dolphins riding the waves her boat created had often made a particular sound, while in early research she found a group of dolphins living off Queensland’s Moreton Island emitted a particular whistle when alone. “That whistle could definitely mean: ‘I’m here, where is everyone?”‘, Ms Hawkins told New Scientist magazine. Ms Hawkins said the sounds were not evidence of a language, but showed the dolphins were communicating “context-specific information”.
“A specialist in linguistics would not call this a language,” she told AAP. “They are wild animals and generally wild animals only make sounds or transmit information that is essential to their survival. “It basically suggests their communication is a lot more complex than what was generally thought.” Ms Hawkins said she hoped to take the project underwater to observe the dolphins’ behaviour and try to more closely match the whistles to actions. “There is only so much information you can get from looking at the surface activity,” she said. “You really need to get under the water and to somehow eavesdrop and look what’s going on with their lives under there.”
Reporter: Jonica Newby / Producer: Paul Schneller / 26 February 2004
PhD student Liz Hawkins is trying to discover, why some of our dolphins have become so quiet, that it appears the noise we humans make is affecting the way dolphins communicate. Many scientists suspect dolphins have a complex vocabulary, but as Catalyst’s Jonica Newby reports, surprisingly little research has been done on dolphin language in the wild. But thanks to the latest software, Liz, is managing to match individual dolphin whistles to behaviours. She has identified 68 distinct whistles – far more than anyone in the world has recorded before. And because she can see the behaviours so clearly, for the first time, she’s been able to work out what many of them mean. And she’s recorded a lot more than she bargained for. This story has the first ever sound recording of a dolphin rape. But, perhaps her most remarkable finding is that dolphins appear to have changed the frequency they use to communicate to one is can’t be interfered with by the noise we’re making in the water.
Narration: For millions of years, dolphins have been communicating with each other, in peace. But lately, they’ve had intruders. So could all this noise be interfering with their channels of communication? That’s what PhD student Liz Hawkins wanted to know.
Liz Hawkins: These boats are very loud which is a prime example of what dolphins have actually got to deal with.
Jonica Newby, Reporter: You can’t even wear headphones when they go past?
Liz Hawkins: No. It really does hurt the ears listening to those boats. And we’ve got dolphins just here.
Narration: Liz is a trainee dolphin interpreter, on assignment here in Byron Bay. She set out discover whether humans were disrupting dolphin talk. But in the process, had an extraordinary insight into the secret language of our coastal dolphins. It all began when Liz started trying to record and decode normal dolphin communication. And that’s not easy.
Liz Hawkins: There they are.
Narration: When we spot them today, they’re right in the middle of the surf break at Watago Beach.
Liz Hawkins: Hey Stumpy.
Jonica Newby, Reporter: Stumpy? Are they surfers?
Liz Hawkins: Are they surfers? Oh for sure.
Narration: Despite the fact scientists suspect dolphins have a complex vocabulary, surprisingly little is known about how they communicate in the wild.
Liz Hawkins: Oh, there’s a whole lot over there on that wave too. You’re joking.
Narration: That’s because they’re notoriously difficult to follow and study, especially when they decide to hang out where the surf is really breaking. But Liz is undeterred, and when the dolphins move to calmer waters, we get our first chance to kill the engines.
Liz Hawkins: Ok – Throw the hydrophone in.
Jonica Newby, Reporter: Yeah, I’ve got it.
Liz Hawkins: Turn her on. See if we can hear anything.
Narration: All of a sudden, we’re eavesdropping on their conversation.
Liz Hawkins: Ah – there’s the calf – What did the calf say? He just did a really intense buzz. which is like a really intense series of clicks.
Narration: The clicks are the dolphins echolocation. But Liz’s real targets are the squawks and the whistles.
Liz Hawkins: There was a little whistle then. Can you hear that?
Narration: It’s these complex whistles scientists believe are most likely to carry encrypted information.
Liz Hawkins: There.
Narration: And while they’re not easy to decode, already Liz has deciphered more than she bargained for.
Liz Hawkins: one day in front of the Cape we recorded a group of dolphins. And what it looked like was 4 males pursuing and chasing a female who really didn’t want to be chased.
Narration: Amazingly, Liz captured one of the only known recordings of a dolphin courtship – more like a rape.
Liz Hawkins: and she would basically put her genitals above the water and she’d keep putting her belly above the water so the males couldn’t get to her. And as she did that there was a really intense emission of whistles, and basically it was the same whistle being called over and over and over again and it was quite a distressed type of call.
Narration: But Liz has also interpreted more benign communications. Mainly here, in the calmer waters of Moreton Island, just near Brisbane. These are wild dolphins. But every night, they gather here for a small feed from the tourists. With this clear water and ideal recording conditions, Liz has managed to identify 68 distinct whistles – more than anyone before.
Jonica Newby, Reporter: Oh yeah, I heard that.
Narration: Scientists already knew each dolphin has it’s own distinct whistle. Called a signature whistle, it’s like an individual dolphin name. But this call is new. Liz has discovered a group whistle – possibly a dolphin surname.
Jonica Newby, Reporter: Is this like their family name?
Liz Hawkins: I predict it is. Basically it’s one whistle which seems to be a contact call. If one member of the pod is in the feeding area by themselves they will constantly emit this whistle,
Narration: She’s also discovered a specific call that initiates play, such as a game of chase.
Liz Hawkins: : So basically one dolphin will come up behind another dolphin and then emit a series of squawks meaning; we’re going to play chase now and you’re it.
Narration: Decoding dolphin is in its infancy, but it’s already clear audible communication is incredibly important to them. That’s why Liz became so concerned – how were the dolphins were coping with this. But it wasn’t until an incident last year that Liz’s concern turned to genuine worry. Liz visited Port Phillip Bay in Melbourne for some additional recordings. But this time, the dolphins were completely, eerily, silent.
Liz Hawkins: I threw my hydrophone and the dolphins were facing us so we should have been able to hear every sound they emitted. Why weren’t they emitting anything?
Narration: At first, she thought her worst fears had come true. Boat noise occurs at roughly the same frequency as normal dolphin communication. So in the face of overwhelming interference, were the dolphins simply giving up and going mute? Or, as Liz began to suspect, were the supposedly silent dolphins actually doing something much cleverer. Back in Byron Bay, the puzzle started to slip into place. The missing piece came as Liz was analysing more dolphin recordings. This visual display shows a normal wild dolphin call.
Liz Hawkins: shall we have a listen?
Jonica Newby, Reporter: sure
Narration: But this is the very different whistle made by a captive dolphin.
Liz Hawkins: You can see it starts in our human hearing range and it goes up into beyond our hearing range. And then the tail end of the whistle comes back just into our human hearing range.
Narration: Remarkably, it appears the captive dolphin has learned to change channels to a higher frequency. Liz thinks the reason is that inside a pool, the normal low frequency sounds would bounce dangerously.
Liz Hawkins: it’s a confined space. And basically if they used their acoustics to the full extent in that environment, it will actually cause them permanent hearing damage.
Narration: But by switching to a higher frequency, they may have found a way to protect themselves. And with the realisation dolphins could change frequency, Liz had a brainwave about the mystery of the silent dolphins from Port Phillip Bay. What if when boats were around, they weren’t silent at all. What if, they too had cleverly worked out how to switch channels.
Liz Hawkins: so it’s actually possible that they’re changing their acoustic channels so to speak a little bit higher to occupy a different niche in the acoustic environment.
Jonica Newby, Reporter: Using dolphin stealth mode.
Liz Hawkins: Dolphin stealth mode yes. Absolutely.
Narration: Frequency switching is a fascinating possibility, and one Liz will spend the rest of her research trying to prove or disprove. But there’s plenty of evidence dolphins are adapting their behaviour to humans. Why not their secret communications too?
Dolphins speak a contextual language
BY Emma Young / December 21, 2007
Listen to dolphins whistling to each other and you could be forgiven for thinking that they are having a conversation. Now we’re a bit nearer to understanding what they might be saying, thanks to a project that has distinguished nearly 200 different whistles dolphins make and linked some of them to specific behaviours. Liz Hawkins of the Whale Research Centre at Southern Cross University in Lismore, New South Wales, Australia, eavesdropped on bottlenose dolphins living off the western coast of Australia for her three-year study. “This communication is highly complex, and it is contextual, so in a sense, it could be termed a language,” says Hawkins, who presented her work at a meeting of the Society for Marine Mammalogy in Cape Town, South Africa, this month.
Dolphins were known to use “signature” whistles to identify themselves to others, but the meaning of the other whistles they make was a mystery. Hawkins recorded a total of 1647 whistles from 51 different pods of dolphins living in Byron Bay, New South Wales. From the starting frequency of the sound, its duration, and its end frequency, she identified 186 different whistle types. Of these, 20 were especially common. Hawkins grouped all the whistles into five tonal classes and found that these groups, and even individual whistles, clearly went with different behaviours. When a pod was travelling, for instance, 57 per cent of the whistles were “sine” whistles, rising and falling symmetrically. But when the dolphins were feeding or resting, they made far fewer whistles of this type. And while socialising, they communicated almost exclusively using flat-toned or rising-toned whistles.
The dolphins often made a particular flat-toned whistle when they rode the waves created by Hawkins’s boat, and it’s tempting to speculate that the whistle is the equivalent of a child going “wheeee!”. And in a group of dolphins living off Moreton Island in Queensland, Hawkins identified a whistle often emitted by an animal when it was on its own. “That whistle could definitely mean: ‘I’m here, where is everyone?'” says Hawkins. Melinda Rekdahl, of the University of Queensland in Brisbane, is also investigating dolphin whistles. She found they make more whistles when they’re being hand-fed than dolphins feeding in the wild. It’s too early to know whether whistles might mean something as specific as “hurry up” or “there’s food over here,” Rekdahl says. “But it’s possible. Dolphin communication is much more complicated than we thought.”
Study finds dolphins speaking “Welsh” dialect
Reuters / May 24, 2007
BANGOR – Dolphins living off the coast of Wales whistle, bark and groan in a different dialect from dolphins off the western coast of Ireland, scientists have discovered. Different physical environments might have contributed to the mammals developing distinctive sets of vocalisations or “dialects”, said Simon Berrow from the Shannon Dolphin and Wildlife Foundation. Berrow supervised a master’s thesis by student Ronan Hickey at University of Wales, Bangor, who analysed 1,882 whistles from the dolphins in the Shannon estuary and bottlenose dolphins in Cardigan Bay in Wales. The study found 32 different sound categories, of which eight were only produced by the Shannon animals. “The idea that the sounds are different is not a bad notion — you’d expect the information had to be different given the diversity of the areas where they reside,” Berrow told Reuters, adding he would use the data to create a dictionary of sounds and pursue the research further, should time and money allow.
Experts Open Dolphin ‘Chat Line’ in Florida / April 7, 2007
A marine mammal rehabilitation facility opened a dolphin “chat line” of sorts Saturday, hoping to teach a deaf dolphin’s unborn calf to communicate. Castaway, as the stranded Atlantic bottlenose dolphin is named, has been recovering at the Marine Mammal Conservancy since Jan. 30. A battery of tests has confirmed she is deaf. Dolphins need to hear echoes of sounds they produce to find food, socialize and defend themselves against predators. “We asked ourselves `How do we get the calf to speak when we have a deaf mother?'” said Robert Lingenfelser, the conservancy’s president. They decided to electronically connect Castaway’s habitat with a lagoon at Dolphins Plus, a research and interactive educational facility a few miles down the Keys Overseas Highway. Underwater speakers and microphones were installed at both locations and connected via phone lines. Castaway should deliver her calf in about a month. “Even before it is born, we want the calf to have an idea of what normal dolphin vocalization is,” Lingenfelser said.
MAYBE IF WE ASK NICELY
TO: rgl [at] marinemammalconservancy [dot] org, info [at] dolphinsplus [dot] com
[TEXT APPROXIMATED] : ‘is there any possibility, for popular educational benefit, to make 24-7 live stream of audio signals discussed above available online? Wouldn’t be that complicated, great research resource (good also for promoting the project)…’