Scientists have discovered what they believe to be the first-ever two-headed bull shark.

A study carried by experts at Michigan State University confirmed the shark was a single shark with two heads, rather than conjoined twins.

“This is certainly one of those interesting and rarely detected phenomena,” Britain’s Telegraph quotes Michael Wagner, the university’s assistant professor of fisheries and wildlife as saying.

“It’s good that we have this documented as part of the world’s natural history,” Prof. Wagner added.

The report disclosed that Prof. Wagner and his team used MRIs to reveal the shark had two distinct heads, hearts and stomachs, with the remainder of the body joining together at the back to form a single tail.

The two-headed bull shark (shown in photo) was found in the Gulf of Mexico on April 7, 2011 after a fisherman cut into the uterus of adult shark and discovered the baby.

It was brought to the marine science department at Florida Keys Community College and then taken to the Michigan University for further analysis, the report said.

It is thought similar creatures may have died before being born.

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

The case was publicised in the Journal of Fish Biology.