It’s a terrifying image to be sure: that blue-coated creature with its underbelly splitting at the neck, two shark heads arching outward. The image has been circulating online recently, with claims that more two-headed sharks are appearing in the water and no one knows why.
Does a Deepwater Horizon oil spill or other water pollution explain such the genetic mutation? Has overfishing caused this? Or was it something in the air? The answer, it seems, isn’t so cut and dry.
Apparently scientists can't stop finding two-headed sharks. Imagine a two-headed 8 foot long shark :/#Headlines pic.twitter.com/m4bxvRRj4Y
— Mario Lopez (@mariolopezviva) November 7, 2016
Two-Headed Sharks: Keep Calm Everyone
First off, these images aren’t recent. They come to us from 2008, and is being recirculated due to a similar study appearing in October, as Popular Science reports. Those scientists discovered a two-headed cat shark, which is the first two-headed beast to appear in an oviparous shark species, a.k.a. a shark that lays eggs. This abnormal offspring likely wouldn’t have survived long, said researchers, and that’s why people haven’t found them previously.
Researchers believe the most plausible explanation was just a case of the old mutations. It not some wild science experiment, but just the randomness of nature. And for other shark species where two-headed offspring have been recorded like blue sharks, it’s just a matter of numbers. Blue sharks carry up to 50 embryos at a time, which is bound to create some anomalies and abnormalities.
One concern, then, is commercial fishing’s influence on the breeding process. Marine scientist Nicolas Ehemann told National Geographic he believes overfishing may cause the gene pool to shrink, and may possibly explain the increase in two-headed fetuses. Meanwhile Felipe Galván-Magaña, who led the 2011 study, suggests that two-headed sharks aren’t more common, but rather there’s just more science journals and media spotlight placed on weird news events like this one. By the way, this is from a guy who also saw a cyclops shark up close, which just sounds freaky.
So are two-headed sharks something you need to start worrying about? Probably not. It’s more fluke than future reading.