Dolphins are multilingual! Scientists record mammals talking 'whale'... in their sleep

Before we know it they'll be speaking French.

Dolphins are so intelligent they can learn to speak a second language- in their sleep.

Captive dolphins in in Port-Saint-Père, France have been recorded sleep talking, scientists have found.

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Intelligent life: Captive dolphins in in Port-Saint-Père, France have been recorded sleep talking, scientists have found (stock image)

But bizarrely, as they rest at night, the aquatic mammals are not making dolphin sounds but whale-like noises.

Péos, Mininos, Cécil, Teha, and Amtan, who were born in captivity, have only ever heard whale sounds as recordings, Science magazine reported.

If the sounds are confirmed to be ‘whale’, it would be the first known instance of dolphins remembering a particular noise and repeating it 'later', researchers say.

The dolphins have only ever heard a whale sing on the soundtrack to their daily shows at the French aquatic park Planète Sauvage.

 

The 21-minute tape to which they perform features several minutes of whale song among other marine noises.

The dolphins have not been known to mimic the whale song during or after performances, according to Science.

But a nine days and eight nights study between November 2008 and May 2009, revealed  25 occasions of never-heard-before dolphin sounds.
Researchers at the University of Rennes hung underwater microphones in the performing dolphins' tank overnight, Discovery reported.

Paying attention: The dolphins have only ever heard a whale sing on the soundtrack to their daily shows at the French aquatic park Planète Sauvage

 A DOLPHIN'S LIFE

• Dolphins are mammals not fish. They are warm-blooded and feed their young milk
• Swimming in circles while they sleep with the eye on the outside of the circle open allows dolphins to keep watch for predators
• They can dive up to 260m deep and stay under for up to 15 minutes
• They use echolocation in the same way as a radar, to find food and navigate
• Each dolphin has a signature whistle that helps individual dolphins recognise each other and collaborate
• Some researchers have said that dolphins should be treated as non-human persons as they are so intelligent

The unusual noises -which make up just one percent of all the sounds recorded - strongly resemble whale song and occur only during ‘rest periods,’ mainly between midnight and 3 am.
Researchers recruited 20 volunteers to compare dolphin whistles and whale songs and found that the dophin's 'whale' is so good, listeners mistook it for real whale song 72 percent of the time.
The noises suggest that the dolphins could be practising their daily shows in their minds at night.
Martine Hausberger of the University of Rennes 1 told Science: 'The shows are a really special time in the day,' because the dolphins are rewarded for their performance. 'There are lots of things they could mimic but don't. ... It's really remarkable the only mimicry [we] found was this one.'
The recordings are ‘the first report of mimicries of sounds heard during special events produced by dolphins in a resting/sleeping context,’ the researchers wrote in the journal Frontiers in Comparative Psychology December 29, 2011. ‘This finding opens very large perspectives for future investigations on dolphin learning processes and 'mental representations.'

This is of interest to all researchers but maybe just a big sign that dolphins in captivity are having anxiety dreams whilst they sleep and re-living a very bad groundhog day!