Five dolphins at a dolphinarium in France have been found doing more tricks than just flipping balls when they have been observed talking in whale song.
Péos, Mininos, Cécil, Teha, and Amtan are performing dolphins at the Planète Sauvage dolphinarium in Port-Saint-Père, France.
Every day they perform tricks to a performance soundtrack which includes excerpts of Humpback whale songs as well as seagulls, music and dolphin whistles.
Researchers from the University of Rennes 1 discovered that the dolphins actually mimicked the whale song after they hung underwater microphones in the tank overnight. One night they recorded over 25 unidentified new sounds and when they compared them to the sounds that the dolphins encountered during the day, they discovered they were nearly impossible to distinguish from real whales either through computer programmes or using human volunteers.
Up until now, dolphins have only been observed to mimic sounds immediately after hearing them. If it is confirmed that the captive-bred dolphins are genuinely copying the soundtrack, it would mark the first time that dolphins have been heard to rehearse new sounds hours after hearing them rather than right away, providing insights into how they store and process memories.
As yet the scientists don’t know whether this is a case of the dolphins talking in their sleep or wanting a bit of privacy to practise their new skills. Co-author Martine Hausberger believes that the dolphins might mimic whales because they are rewarded for performing well and this primes the brain to learn and remember.
"There are lots of things they could mimic but don't...It's really remarkable the only mimicry found was this one."
Future studies will use electroencephalogram recordings of the dolphins' brains at night to establish if the dolphins are asleep and dreaming when they mimic, which might mean that dreams help dolphins etch new information into their memories, just like in humans.
For more information, and to hear the dolphins and make your own mind up, see the paper: Kremers D, Jaramillo MB, Böye M, Lemasson A and Hausberger M (2011) Do dolphins rehearse show-stimuli when at rest? Delayed matching of auditory memory. Front. Psychology2:386. doi: 10.3389/fpsyg.2011.00386
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