Researchers Confirm Discovery of Two-Headed Bull Shark

Researchers now say that the two-headed bull shark discovered in Gulf of Mexico April 7, 2011, was indeed a single shark that had two heads, and that it wasn't a conjoined twin.

The specimen of the double-headed bull shark was found by a fisherman in the uterus of an adult female shark near Florida Keys. Researchers from the Michigan State University said that the double-headed shark wouldn't have survived in the wild for long.

Michael Wagner, MSU assistant professor of fisheries and wildlife, said that although there have been reports of other sharks like blue sharks with two heads, this is the first time that a two-headed shark has been discovered among bull sharks.

For the study, researchers from MSU took magnetic resonance images of the specimen and found that the shark had two distinct heads, hearts and stomach, while the rest of the body ended as a single tail.

The mutation seen in the bull shark specimen also occurs in humans. The resultant condition is called "axial bifurcation," where the embryo begins to split into two individuals, but stops doing so somewhere in the middle, reports Livescience.

"This is certainly one of those interesting and rarely detected phenomena. It's good that we have this documented as part of the world's natural history, but we'd certainly have to find many more before we could draw any conclusions about what caused this," Wagner said in the news release.

Researchers say that finding anomalies in other animals, especially the ones that are bred, are easy, as breeders spot these differences early. However, in case of sharks, finding such oddities becomes difficult.

"You'll see many more cases of two-headed lizards and snakes. That's because those organisms are often bred in captivity, and the breeders are more likely to observe the anomalies," he said.

Wagner said that few people might want to connect the discovery with the recent oil spill in the region.

"Given the timing of the shark's discovery with the Deepwater Horizon oil spill, I could see how some people may want to jump to conclusions. Making that leap is unwarranted. We simply have no evidence to support that cause or any other," Wagner said.

The studied shark specimen was first brought to marine science department at Florida Keys Community College. The study is published in the Journal of Fish Biology.