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13th Dec 2023

Dolphin with thumbs discovered in scientific first

Charlie Herbert

Dolphin with 'thumbs' discovered in scientific first

Rise of the planet of the dolphins

Scientists have discovered a dolphin that appears to have hooked thumbs on its flippers.

Researchers from the Pelagos Cetacean Research Institute were conducting boat surveys off the coast of Greece when the spotted the animal on two occasions.

Alexandros Frantzis, president of the research institute, said that despite the sea mammal’s unique flippers it was able to keep up with the rest of its pod.

He told Live Science: “It was the very first time we saw this surprising flipper morphology in 30 years of surveys in the open sea and also in studies while monitoring all the stranded dolphins along the coasts of Greece for 30 years.”

Frantzis managed to capture the thumbed dolphin on camera.

He theorised that the hooked flippers were most likely “the expression of some rare and ‘irregular’ genes” that emerged as a result of constant interbreeding.

Alexandros Frantzis/Pelagos Cetacean Research Institute

This was backed up by Lisa Noelle Cooper, a mammalian specialist, who said: “I’ve never seen a flipper of a cetacean that had this shape.

“Given that the defect is in both the left and right flippers, it is probably the result of an altered genetic program that sculpts the flipper during development as a calf.”

Dolphins and whales do have finger bones though, which are arranged into human-like ‘hands’ in their flippers.

This includes a thumb bone, with cells building up around dolphins’ forelimb bones in the womb to form flippers.

Cooper explained: “It looks to me like the cells that normally would have formed the equivalent of our index and middle fingers died off in a strange event when the flipper was forming while the calf was still in the womb.”

But she added that whilst the thumb “may have some bone inside of it, it certainly isn’t mobile.”

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