One might say this dolphin sticks out like a sore thumb.
Researchers studying marine life in the Gulf of Corinth, off the coast of Greece, spotted a very unusual sight this summer, in the form of a dolphin that appears to be growing “thumbs” from its flippers.
Researchers with the Pelagos Cetacean Research Institute (PCRI) spotted the dolphin on two occasions over the summer.
“It was the very first time we saw this surprising flipper morphology in 30 years of surveys in the open sea,” Alexandros Frantzis, scientific coordinator and president of the research institute, told LiveScience
The team at PCRI, a scientific non-profit that studies whales, dolphins and porpoises, was able to capture photos of the so-called thumbs, and first shared their finding in a YouTube video in October.
Despite its unusual appearance, the dolphin had no problem keeping up with the rest of its pod and was seen “swimming, leaping, bow-riding, playing” just as well as its podmates, Frantzis said.
Don’t be alarmed, though. This doesn’t appear to be a situation where dolphins are evolving to have thumbs, nor do researchers believe the dolphin is sick or suffering.
“The fact that this irregularity is found in both flippers of the dolphin and no injuries or skin lesions are present explains why this could not be an illness, but an expression of very rare genes,” Frantzis told USA Today.
Bruna Farina, a doctoral student specializing in paleobiology and macroevolution at the University of Fribourg in Switzerland, explained to LiveScience that dolphin fins are arranged into a human-like “hand” and encased in a flipper.
Essentially, dolphins do have thumbs, but they’re usually contained inside the flipper’s soft tissue.
The dolphin in this case is likely missing some of those fingers, as well as the tissue that surrounds them.
“The hook-shaped ‘thumb’ may have some bone inside of it, but it certainly isn’t mobile,” Lisa Noelle Cooper, an associate professor of mammalian anatomy and neurobiology at the Northeast Ohio Medical University, told LiveScience.
Further allaying people’s fears of dexterous dolphin overlords, she added that “no cetaceans have mobile thumbs.”