Scientists at Michigan State University have confirmed a shark found off the coast of Florida is the first two-headed bull-shark ever discovered, and not simply conjoined twins. Marine biologists are calling it the rarest two-headed shark specimen ever recorded.
Michael Wagner, assistant professor of fisheries and wildlife at Michigan State, and his team used MRIs to discover the shark had two distinct heads, two hearts, and two stomachs while the rest of the body and tail were one.
"This is certainly one of those interesting and rarely detected phenomena," said Michael Wagner, the assistant professor of fisheries and wildlife at Michigan State.
"It's good that we have this documented as part of the world's natural history."
The baby shark was found in the uterus of a bull-shark caught in the Gulf of Mexico on April 7, 2011. Still alive, the fisherman handed the shark over to experts at the marine sciences department of Florida Keys Community College and it was then sent to Michigan State University for further analysis.
Scientists are not sure what caused the mutation in the shark, who later died. Some suggest it could have something to do with the May 2010 oil spill from BP’s Deepwater Horizon disaster.
Even if it had been birthed in the wild, Wagner said the anomaly would not have allowed it to live for very long.
"When you're a predator that needs to move fast to catch other fast-moving fish...that'd be nearly impossible with this mutation," he said.
The deformity, called “axial bifurcation,” occurs when an embryo does not completely split into two separate organisms.
"You'll see many more cases of two-headed lizards and snakes," said Prof Wagner, whose results were published in the Journal of Fish Biology. "That's because those organisms are often bred in captivity, and the breeders are more likely to observe the anomalies."