World's first two-headed bull shark discovered

Scientists have discovered the world's first two-headed bull shark in the Gulf of Mexico.
The study led by Michigan State University confirmed the specimen, found on April 7, 2011, was a single shark with two heads, rather than conjoined twins.
There have been other species of sharks, such as blue sharks and tope sharks, born with two heads. This is the first record of dicephalia in a bull shark, said Michael Wagner who confirmed the discovery.
"This is certainly one of those interesting and rarely detected phenomena," Wagner said in a statement.
"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," he said.

The difficulty of finding such oddities is due, in part, to creatures with abnormalities dying shortly after birth. In this instance, a fisherman found the two-headed shark when he opened the uterus of an adult shark. The two-headed shark died shortly thereafter and had little, if any, chance to survive in the wild, according to the study that appears in the Journal of Fish Biology.
"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," Wagner added.
Wagner and his team were able to detail the discovery with magnetic resonance imaging. Without damaging the unique specimen, the MRIs revealed two distinct heads, hearts and stomachs with the remainder of the body joining together in back half of the animal to form a single tail.