Dolphin with ‘thumbs’ surprises scientists in first-ever discovery

Hybrid-seeming creatures are apparently not limited to Greek mythology.

Scientists are scratching their heads over the discovery of a dolphin in Greece, which appeared to possess a pair of “thumbs,” marking the only instance in which they’d witnessed such an aquatic anomaly.

“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,” Alexandros Frantzis, the scientific coordinator and president of the Pelagos Cetacean Research Institute, told LiveScience in an email.

He and the research team spotted the digit-sporting dolphin on two separate occasions last summer while conducting boat surveys in the Gulf of Corinth in the Ionian Sea.

Despite being one of 1,300 striped dolphins living in the gulf, it was the only individual to give researchers a permanent two thumbs up.

Like an ocean-going version of redeemed “misfit” Rudolph the Red-Nosed Reindeer, the dolphin’s unusual thumb-like appendages apparently haven’t prevented it from being accepted by the pod.

Researchers said that the cetacean was reportedly “swimming, leaping, bow-riding, playing” with other dolphins, per Frantzis, who snapped pics of the aquatic anomaly.

While certainly strange, the scientists don’t believe that the oceanic hitchhiker’s thumbs are caused by illness, but rather due to a genetic aberration caused by constant inbreeding.

Lisa Noelle Cooper, an associate professor of mammalian anatomy at the Northeast Ohio Medical University, agreed with the assessment, explaining: “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.” 

Interestingly, all cetaceans — the family comprising dolphins, whales and porpoises — possess human-like forearms and “fingers,” an evolutionary holdover from eons ago when the species were four-legged terrestrial beings.

However, these marine mitts are encased in flippers, concealing them from sight like a blubbery glove.

In the case of the aforementioned thumb-bearer, Cooper believes that a genetic birth defect caused the critter to be born without fingers or the tissue sheath, leaving it with just a thumb and “ring finger.”

Although the big digit might have a bone, it isn’t operational, per the scientist.

In other words, it serves no identifiable porpoise.

Then again, perhaps it’s better that cetaceans don’t have useable thumbs; otherwise, boaters could really be at the mercy of the notorious ship-scuttling orcas.

Or perhaps the so-called Russian spy beluga could be taught to arm and disarm bombs on its own.