I don’t know about you, but for some reason I remember more than one teacher telling me that opposable thumbs were what set us apart from a majority of other mammals on the planet.

Back then, I thought that was kind of boiling it down, but after living in the world for awhile I don’t know. Maybe that really is all there is different.

At least, all that used to set us apart.

Because now, at least one dolphin has one too. Sort of.

Scientists at Greece’s Pelagos Cetacean Research Institute say they’ve seen the dolphin with a thumb twice while doing boat surveys in the Gulf of Corinth.

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

Several different types of dolphins live in the Gulf, including Risso dolphins and striped dolphins. The special case was one of the latter.

Researchers think that the genetic abnormality could be caused by inbreeding, since the dolphins in the Gulf are cut off from the Mediterranean Sea (and a bigger breeding pool).

The dolphin does not seem affected, and has been observed “swimming, leaping, bow-riding, and playing” with the rest of its kind.

And get this: scientists have apparently always known that cetaceans (dolphins, whales, porpoises, etc) have “forelimbs replete with extender phalanges” (or finger bones).

In other words, they have all of the bones that go in a hand – including a thumb – but the digits are concealed by their flippers.

Lisa Noelle Cooper, a mammalian anatomy expert, says this dolphin actually seems to be missing some of those digits.

“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.”

The “thumb” isn’t opposable, so I guess we still have a leg up.

On land, anyway.

Thought that was fascinating? Here’s another story you might like: Why You’ll Never See A Great White Shark In An Aquarium