« Hope for rhinos after all: translocated animals have babies | Main | How the biggest stars are born: U of T research offers new clues »


Two-headed bull shark fetus found in Gulf of Mexico

A handout image of the two-headed bull shark fetus. (Courtesy of C. Michael Wagner)

File this one under "Weird Science News."  A fisherman has found a two-headed bull shark fetus in the Gulf of Mexico, according to a study published in the Journal of Fish Biology on Monday.

The 2011 discovery is the first-ever recorded case of monosomic dicephalia in a bull shark (Carcharhinus leucas), reports C. Michael Wagner, an assistant professor of fisheries and wildlife at Michigan State University.

Monosomic dicephalia is the scientific term to describe "an individual with two heads that eventually fuse into a single lower torso," Wagner wrote in an email to the Toronto Star.

A handout X-ray image of the two-headed bull shark fetus. (Courtesy C. Michael Wagner)

A fisherman caught a female bull shark near the Florida Keys on April 7, 2011, and after opening up the animal's uterus, found the live two-headed fetus. 

The fetus was likely near term, Wagner said. It later died.

The fisherman gave the unusual fetus to researchers to study.

The fetus was found to have two separate heads, stomachs and hearts but it had a single body and tail, Wagner and his team discovered.

"The heads and internal organs appeared well developed in that everything was present in the MRI imagery," Wagner wrote in his email.
"However, the animal was much smaller than it should have been, particularly in the back half, and animals with a severe deformity like this one rarely survive to birth, or die soon after being born." 


So what does this discovery mean -- if anything -- for the health of the world's oceans?

"Nothing," Wagner said in his email to the Star. "This is a single observation of a rarely observed phenomenon, so it merits inclusion in the scientific literature. But, because we cannot ascribe any particular cause to this event, we cannot make an inference about the circumstances that led to the occurrence.

"However, it does have some additional value from the perspective of the general public," he continued. "These anomalous creatures are fascinating, and provide a segue for journalists such as yourself to engage in a discussion about more important topics, like the health of the world’s oceans."

Wagner added that the journal Nature published a paper last year on a proposal to measure the health of the oceans.

Lorianna De Giorgio is the Toronto Star's Foreign Web Editor. Follow her on Twitter @ldegiorgio



Feed You can follow this conversation by subscribing to the comment feed for this post.

Look at what we do to other species...sad.

It does, however, seem to have had two lovely sets of teeth!

The comments to this entry are closed.

The World Daily

  • The Star's foreign desk covers the best stories from the around the globe, updated throughout the day.