Skip to: Content
Skip to: Site Navigation
Skip to: Search


2-headed shark fetus discovered by fisherman

2-headed shark fetus: A fisherman in the Florida keys caught a bull shark that contained a rare find. Inside was a shark fetus with two heads. 

By Douglas MainOurAmazingPlanet Staff Writer / March 25, 2013

The two-headed bull shark fetus. It's about 8 inches (20 centimeters) from head to head.

Journal of Fish Biology / C. M. Wagner et al

Enlarge

When a fisherman caught a bull shark recently off the Florida Keys, he came across an unlikely surprise: One of the shark's live fetuses had two heads.

Skip to next paragraph

The fisherman kept the odd specimen, and shared it with scientists, who described it in a study published online today (March 25) in the Journal of Fish Biology. It's one of the very few examples of a two-headed shark ever recorded — there about six instances in published reports — and the first time this has been seen in a bull shark, said Michael Wagner, a study co-author and researcher at Michigan State University.

Technically called "axial bifurcation," the deformity is a result of the embryo beginning to split into two separate organisms, or twins, but doing so incompletely, Wagner told OurAmazingPlanet. It's a very rare mutation that occurs across different animals, including humans.

"Halfway through the process of forming twins, the embryo stops dividing," he said.

The two-headed fetus likely wouldn't have lived for very long in the wild, he said. "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.  [See the two-headed shark.]

Wagner said the description of the deformed shark may someday help better understand how these deformities arise in sharks and other animals.

Two-headed snakes and turtles can be bought from certain specialty breeders, and there is a small market for such creatures, Wagner said.

Several of the few examples of two-headed sharks available today come from museum specimens from the late 1800s, when deformed animals and other macabre curiosities fetched high prices, he said.

Another reason the two-headed shark likely wouldn't have survived: its small body. "It had very developed heads, but a very stunted body," Wagner said. There's only so much energy that can go into the body's development, and it went into the shark's double noggins, he added.

Email Douglas Main or follow him @Douglas_Main. Follow us @OAPlanetFacebook or  Google+. Original article on LiveScience's OurAmazingPlanet

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

  • Weekly review of global news and ideas
  • Balanced, insightful and trustworthy
  • Subscribe in print or digital

Special Offer

 

Editors' picks

Doing Good

 

What happens when ordinary people decide to pay it forward? Extraordinary change...

Endeavor Global, cofounded by Linda Rottenberg (here at the nonprofit’s headquarters in New York), helps entrepreneurs in emerging markets.

Linda Rottenberg helps people pursue dreams – and create thousands of jobs

She's chief executive of Endeavor Global, a nonprofit group that gives a leg up to budding entrepreneurs.

 
 
Become a fan! Follow us! Google+ YouTube See our feeds!