Just when we think we have the ocean figured out, it goes and springs something like this on us — a fisherman caught a bull shark off the Florida Keys, and when he cut the thing open he found two live fetuses. Well, three if you count the one with two heads.
That's right, one of the fetuses had two fully-formed heads on its tiny body, according to National Geographic.
The fisherman found the thing alive, but it died shortly afterward and he turned it over to scientists. The scientific team, led by C. Michael Wagner at Michigan State University, said it was the first known case of this happening in bull sharks. Their findings were published in the Journal of Fish Biology on March 25. Wagner said that studying creatures with rare deformities like this one will give invaluable insight into developmental processes.
This rare genetic anomaly, called "axial bifurcation," occurs when two embryos are dividing in the womb but for some reason cease splitting. The two sharks, which would have been twins, were forever fused by this mysterious biological process. After giving the little guy an MRI, the team discovered that it had two distinct heads, hearts and stomachs, and that the rest of the animal was fused together in its tiny underdeveloped body. The animal likely would have died early on in the wild due to its body size, according to Wagner, who also said that this kind of deformity is more often seen in lizards and other captive-bred animals because breeders encounter them more frequently.
While this is the first two-headed bull shark found, it's far from the only two-headed critter discovered. Here are some of our favorite other (sometimes disturbingly cute) bifurcations:
Snake(s) (as if one snake head wasn't creepy enough)
And of course...