A recent Instagram photo snapped of an Australian wave had the internet divided as to whether the finned animal lurking in the water was a shark or a dolphin ... or some sort of shark-dolphin hybrid.
Kellie Wilson, who took the photo off the coast of Duranbah Beach, joked in the caption that she didn't know what she was looking at. "Shark or dolphins?!? Or shark and dolphins? Or just a sharky looking dolphin ...?!"
With that, the internet was off and running. A Daily Star poll had 81 percent of people saying "shark," 12 percent saying "dolphin" and 4 percent of voters thinking it was half-shark half-dolphin.
The confusion seems to come from the tail versus the rest of the body.
Per Daily Star, one defining factor of a dolphin's body is that its pectoral fins are closer to the head than the dorsal fin — as can be seen above. But, dolphins have horizontal tails and sharks have vertical tails.
The animal in question appears to have a shark tail, with the body of a dolphin.
The majority of its body being dolphin-like means that the vertical tail is probably an optical illusion, at least according to SeaWorld marine expert Trevor Long.
"I think it's definitely a dolphin," he told Sunshine Coast Daily. "It only looks like a flat tail because it's being distorted by the angle of the wave.
You can also see in the photo that there are at least three of the animals in the waves, and sharks don't usually travel in groups.
So, probably a dolphin, probably not shark — and definitely not a shark-dolphin hybrid.
The mystery of whether it could be a shark-dolphin hybrid can be cleared up pretty easily — because that's impossible. As Newsweek noted, sharks are fish and dolphins are mammals. That kind of mating just wouldn't work.
Newsweek reports that "their most recent common ancestor was an early jawed fish that lived around 290 million years ago." Today's dolphins are closer in relation to deer than to sharks.
Sharkphins (or dorks) are just not a thing.
But real ocean-animal hybrids aren't unheard of. There are such things as whale-dolphins (a mix of false killer whale and bottlenose dolphin).
These are more commonly known as wholphins.
Newsweek reported a skull was once found attributed to a beluga whale and narwhal offspring.
This is called a narluga.
Meanwhile, Smithsonian reports there have also been grolar/pizzly bears.
Aka polar bears who mated with grizzly bears.
The world is filled with some interesting cohabitation between species — but a half-fish half-mammal like a shark-dolphin wouldn't just be a social media conundrum.