Dolphin Vocalisation

Passive Research | Active Research

Passive Research

Dolphin – Wikipedia, the free encyclopedia:
(http://en.wikipedia.org/wiki/Dolphins#Vocalizations)
• capable of making a broad range of sounds using nasal air sacs located just below the blowhole
• roughly three categories of sounds can be identified
• whistles, burst-pulsed sounds, and clicks
• echolocation clicks are amongst the loudest sounds made by animals in sea

Whistles
• are used by dolphins to communicate, nature and extent of their ability to communicate in this way is not known
• at least some dolphin species are capable of sending identity information to each other using a signature whistle; a whistle that refers specifically to the identity of a certain dolphin

Burst-pulsed sounds
• are also used for communication, but again the nature and extent of communication possible this way is not known

Clicks
• are directional and used by dolphins for echolocation and are often in a short series called a click train, the rate increasing when approaching an object of interest

Dolphin and Whales Sounds:
(http://neptune.atlantis-intl.com/dolphins/sounds.html)
• have voices a lot different from most other mammals
• limited visibility under water made sounds and hearing very important
• even in complete darkness they can find their way through the ocean and also find their food
• sounds of the whales are not produced with their mouth/beak but only inside their blow-hole
• also use higher frequencies that reach far beyond our hearing capabilities
• use sound not only to communicate, but also to “see”
• SONAR: SOund NAvigation Ranging
• echolocation clicks are amongst the loudest sounds made by animals in sea
• even in complete darkness they can find their way through the ocean and also find their food
• whistling (high pitched sounds)
• in general the whistles are for communication and the clicks is the SONAR

• Bottlenose Dolphins: .mp3 file (64 kb)
• Spottet Dolphins: .mp3 file (57 kb)
• Common Dolphin: .mp3 file (59 kb)
• Common Dolphin (lots of sonar): .mp3 file (101 kb)
• False Killer Whale: .mp3 file (83 kb)
• Pilot Whale: .mp3 file (103 kb)
• Risso’s Dolphin (whistle and sonar): .mp3 file (93 kb)
• Risso’s Dolphin (just the “whistle): .mp3 file (27 kb)
• Sperm Whale: .mp3 file (72 kb)

Dolphin: Breathing, Sleeping:
(http://www.kidscruz.com/DOL_BS.HTM)
• the blowhole on their back makes it possible for them to roll up to the surface, exhale and inhale, then roll back down below the surface
• occasionally, we hear them getting choked with water in their blowhole and they will stay at the surface, coughing, until they clear their airway
• when they come to the surface, they clear that water pretty quickly (about 100 miles per hour!) which sometimes makes for a large spray

Dolphin Sounds – Hear Them Yourself
(http://www.dolphinear.com/data/dolphin_sounds.htm)
• Ancient Greek mariners listened to the sounds of dolphins through the hulls of their ships

Whistles
• are unique to each individual animal – much like our own voices
• appears that dolphins use these ’signature whistles’ like we use names
• you often hear a loud whistle from a nearby dolphin, followed by a similar sounding whistle from another dolphin
• sort of like a sound ‘handshake’ or greeting

Clicks
• generally used for some form of echolocation
• echolocation works like ‘radar’ and is used by dolphins to find food – like schooling fish
• dolphin makes a ‘click’ which travels through water, bounces off an object like a fish, and then hears the echo

Chirps (Burst-pulsed sounds)
• which are tones of varying frequency – their purpose is not know
• dolphin sounds are well within the hearing range of people
• echo location clicks can range up to about 150,000 Hz (about 8 times higher than the normal human hearing range)
• a lot of these clicks occur at frequencies as low as about 2,000 Hz
• so people can easily hear them with the proper hydrophone

• reported that cetaceans (dolphins and whales) have a large portion of their brains devoted to auditory senses
• may be able to convert sound into an acoustic image in a section of their brains which allows them to ’see’ in the darkness of the ocean, or in the murky waters of river deltas
• there are many ‘noise’ sources in the ocean that could act to ‘illuminate’ objects with sound that cetaceans detect:
• in shallow tropical and semi-tropical waters, snapping shrimp product continuous ‘clicking’ noises
• these may allow cetaceans to ’see’ fish without the need to use their own echo location – which might alert fish of their presence
• further out in the ocean, ambient sounds from wave action may serve the same purpose

Song of a Humpback Whale: .wav file

Dolphin Whistles: .wav file

Snapping Shrimp: .wav file

Boat with Diesel Engine – 650 ft away: .wav file

Animal echolocation – Wikipedia, the free encyclopedia:
(http://en.wikipedia.org/wiki/Animal_echolocation)
• echolocation, also called Biosonar, is the biological sonar used by several mammals
• animals emit calls out to the environment, and listen to the echoes of those calls that return from various objects in the environment
• use these echoes to locate, range, and identify the objects
• used for navigation and for foraging (or hunting) in various environments

Acoustic Features of Bat Echolocation Calls:
• Frequency Modulation and Constant Frequency
• Intensity
• Harmonic Composition
• Note Duration

Toothed Whales:
• toothed whales emit a focused beam of high-frequency clicks in the direction that their head is pointing
• sounds are generated by passing air from the bony nares through the phonic lips
• these sounds are reflected by the dense concave bone of the cranium and an air sac at its base
• the focussed beam is modulated (varying in strength, tone and pitch) by a large fatty organ known as the ‘melon’ – this acts like an acoustic lens because it is composed of lipids of differing densities
• most toothed whales use clicks in a series, or click train, for echolocation, while the sperm whale may produce clicks individually
• different rates of click production in a click train give rise to the familiar barks, squeals and growls of the bottlenose dolphin
• a click train with a repetition rate over 600 per second is called a burst pulse (chirp)
• In bottlenose dolphins, the auditory brain response resolves individual clicks up to 600 per second, but yields a graded response for higher repetition rates

Human echolocation – Wikipedia, the free encyclopedia:
(http://en.wikipedia.org/wiki/Human_echolocation)
• actively create sounds, such as by tapping their canes or by making clicking noises with their mouths
• similar in principle to active sonar and to the animal echolocation employed by some animals, including bats and dolphins
• by interpreting the sound waves reflected by nearby objects, a person trained to navigate by echolocation can identify the location and sometimes size of nearby objects and use this information to steer around obstacles and travel from place to place
• however, since humans make sounds with much lower frequencies and slower rates, human echolocation can only picture comparatively much larger objects than other echolocating animals

Dolphin Sounds:
(http://www.junglewalk.com/sound/Dolphin-sounds.htm)

Dolphin
0.170MB WAV Hear Sound
Scholastic
Dolphin sonar clicks

Dolphin
0.180MB AIF Hear Sound
Pelotes Island Nature Preserve
Dolphin

Bottlenose Dolphin
Streaming RAM Hear Sound
National Geographic – Creature Feature Archive
Bottlenose Dolphin

river dolphin
0.050MB MP3 Hear Sound
John van der Woude’s birding trip reports
river dolphin call

Risso’s dolphin
0.040MB WAV Hear Sound
Università degli Studi di Pavia
Audio of Risso’s dolphin

Bottlenose Dolphin
MP3 Hear Sound
David”s Whale and Dolphin Watch
Dolphins and whales have voices, but it’s a lot different from most other mammals. The limited visibility under water made sounds and hearing very important for them

Spottet Dolphin
MP3 Hear Sound
David”s Whale and Dolphin Watch
Dolphins and whales have voices, but it’s a lot different from most other mammals. The limited visibility under water made sounds and hearing very important for them

Common Dolphin
MP3 Hear Sound
David”s Whale and Dolphin Watch
Dolphins and whales have voices, but it’s a lot different from most other mammals. The limited visibility under water made sounds and hearing very important for them

Common Dolphin
MP3 Hear Sound
David”s Whale and Dolphin Watch
Dolphins and whales have voices, but it’s a lot different from most other mammals. The limited visibility under water made sounds and hearing very important for them

Risso’s Dolphin
MP3 Hear Sound
David”s Whale and Dolphin Watch
The whistle and the sonar. “When you listen to the sounds you will usually hear two kinds of sounds. One that sounds like whistling (high pitched sounds) and one that sounds like a rattle or clicking. In general the whistles are for communication and the clicks is the SONAR.”.

Risso’s Dolphin
MP3 Hear Sound
David”s Whale and Dolphin Watch
The whistle

Risso’s dolphin
WAV Hear Sound
Università degli Studi di Pavia
Risso’s dolphin

Bottlenose Dolphin
Streaming RAM Hear Sound
BBC
Bottlenose Dolphin audio clip

Bottlenose Dolphin
MP3 Hear Sound
National Geographic
Bottlenose Dolphin sound clip

Bottlenosed Dolphin
AIFF Hear Sound
VivaNatura
Bottlenosed Dolphin sound

Dolphin
0.020MB WAV Hear Sound
Harry Foundalis Home Page
Dolphin

Active Research

Kian Peen, NUS MMRL
Research Engineer

“Dolphins in general make several types of calls, the most widely studies being “Whistles” (mainly use for social interaction among con-species) and “Echolocation” (for navigation and foraging). Other types of calls include barks, chirps, growls, squarks etc, depending on species. If you want to make it realistic, it can be a problem trying to find all the different types of vocalisations from the different species. Moreover, I personally do not know exactly what type of vocalisations they tend to make during the capture or killing.”

Dr Elizabeth Taylor, NUS MMRL
Head

• signature whistles unique to each individual dolphin]
• relatives learn from each other
• distress calls hardly sound distressing to humans but they can be repeated
• look into types of dolphin vocalizations:
• whistles
• grunts
• barks
• groans
• squawks
• sonar (echo location / clicks)

Dolphin Lagoon, Sentosa:
March 3, 2008

The team made a casual visit to the Dolphin Lagoon to see if we could arrange a recording session with the pink dolphins. We did not manage to speak to the trainers there, and were told to seek the Marketing Department for advice. A few weeks later, although we managed to get in contact with the person in charge, we decided to drop the idea of recording in Dolphin Lagoon, which is of course a commercial organization that supports captives dolphins.

Social Behavior: When undisturbed, pink dolphins are slow swimmers, traveling at a speed of approximately 15 km/hr. They are always found in small groups, called pods, consisting up to 9 individual dolphins.

Communication: The dolphins communicate through sounds like clicks, moans, whistles, trills, and squeaks. Audible sounds are also produced from their blowholes through vocalization. The dolphins also use clicks for echolocation to navigate and detect prey and obstacles up to 650 feet (198 meters) away.