Voices of the Sea

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Episode 3 of 3

Duration: 1 hour

Whales and dolphins are nature's supreme vocalists, with a repertoire to put an opera singer to shame. The mighty sperm whale produces deafening clicks in its blowhole which it uses to locate giant squid two miles down in the ocean abyss, while migrating narwhals use similar sounds to pinpoint vital breathing holes in Arctic ice-floes.

The pink boto dolphin creates bat-like ultrasonic clicks to 'see with sound' and to catch fish in the murky waters of the Amazon River, and also uses whistles and chirps for social conversations.

Killer whales in the North Sea use wolf-like howls to round up the herring shoals which they feed on, and they and other dolphins also use percussive tail slaps and splashing leaps to signal to each other. One group of bottlenose dolphins in Brazil has even learned to communicate with fishermen in a unique partnership.

But the most famous and mysterious voice of all the Ocean Giants surely belongs to male humpback whales, whose haunting operatic performances may last several hours and seem to be about singing purely for the sheer pleasure of making music.

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  • Whale music

    Whale music

    By Phil Chapman – series producer

    The song of the humpback whale is a marvel of nature. Only the males sing and with such power that the sound can carry a hundred miles. A recital may last for several hours and generally includes half a dozen or more themes which are repeated in various combinations. It’s more jazz than opera, as individuals improvise new phrases which are then picked up by other males, so that the song-cycle changes and evolves over time.

    After years of research, scientists have ruled out the obvious reasons why male humpbacks might choose to sing: it doesn’t attract females and it doesn’t repel rivals. Maybe the whales simply enjoy making music? Cameraman Didier Noirot has probably been as close to singing humpbacks as anyone on earth, and he’s impressed. ‘The song of the whale, for me that’s the voice of the sea’, says Didier, ‘when you come close to a male that sings, all your body shakes and vibrates. You can’t stay there, you have to move away. It’s so strong, so strong...’

    The humpback whales were filmed with permission from Hawaii National Oceanic and Atmospheric Administration permit No. 14451.

    Listen in on a humpback whale opera
  • Botos


    River dolphins belong to a distinct lineage of toothed whales that have made their home in fresh water. It might seem a strange lifestyle choice for a dolphin, but it makes excellent evolutionary sense. In the oceans, dolphins are highly successful nocturnal hunters thanks to a fortunate by-product of their ancestry as air-breathing mammals. Air is a better medium than water for sound production, and dolphins have evolved the ability to generate ultra-high-frequency sounds inside the airways that link to their blowhole. They use these sounds for echolocation – much as bats do. This advanced technology makes them effective hunters not just at night, but also in the muddy waters of river estuaries where fish can’t see them coming. The dolphins can use echolocation to navigate and detect their prey.

    In the muddy Amazon, the boto river dolphin has become a super-predator, with few enemies (until humans arrived) and a vast resource of fish to feed on. Its long crocodile-like snout contains pointed teeth for gripping slippery fish and crushing teeth to crunch up armoured prey (many Amazon fish have armoured scales, and botos also eat shellfish).

    Filming botos for Ocean Giants, Doug Allan was able to get underwater shots in a lagoon at the confluence of the Amazon and the Rio Negro whose waters are virtually silt-free. Coming within inches of Doug, the botos scanned him with a buzz of rapid echolocation clicks – up to nine hundred clicks per second at frequencies up to 100kHz – way beyond human hearing range – producing a strange tickling sensation. With their tiny eyes, peculiar flexible necks, long snouts, huge front fins and bizarre pink colour, getting this close to a boto feels pretty close to an alien encounter. As Doug says, 'these are the weirdest dolphins that I’ve ever seen. They can even swim backwards. I've never seen that in a dolphin before!'

    Watch Doug Allen's boto encounter
  • Sperm Whale (Dominica)

    Sperm Whale (Dominica)

    The clicks of a baby sperm whale can travel over a mile.


Phil Chapman
Executive Producer
Sara Ford
Series Producer
Mark Brownlow
Series Producer
Phil Chapman
Stephen Fry


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