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Two-Headed Blue Shark Surfaces (Another One!)

Two-headed blue shark held by hand

This two-headed blue shark fetus was removed from its mother by fisherman Christopher Johnston in 2008, off the coast of Australia. Photograph by Christopher Johnston

We recently wrote about a two-headed bull shark found by fishermen. One of our readers, Christopher Johnston, then sent us an email with photos he had taken on September 27, 2008 of a similarly surprising find: a two-headed blue shark. As far as we know these photos have never been published anywhere before.

As we previously reported, there have been only about a half dozen reported cases of two-headed sharks. The phenomenon arises through conjoined development of twins, the same process that produces what used to be called Siamese twins in people. (See more examples of two-headed animals.)

In January 2011, scientists published a review of two-headed blue sharks in the journal Marine Biodiversity Records. The malformed female blue shark embryos the scientists examined had been found inside a pregnant adult female that had been caught in the Gulf of California off the western coast of Baja California Sur, Mexico.

The researchers, led by Felipe Galván-Magaña, wrote, “Abnormal sharks showed a symmetric bicephaly that could be caused by the high number of embryos found in the uterus of the blue shark, which is the most fecund species of shark in the world. The abnormality probably began during the embryonic development.”

In the case of the two-headed blue shark that appears in the photos in this post, Johnston told us that he found it while working as a longline fisherman in the Indian Ocean. “I can’t remember exactly where we were, somewhere between 200 and 900 miles off West Australia,” Johnston told Ocean Views.

“We pulled up a pregnant blue shark, cut it open, and there was the tw0-headed one,” he said.

“It was about two-thirds the size of the rest of the pups in length. I put it in the tank on the deck. It swam a little while, but it couldn’t swim properly, it just swam in one spot as if it were on a treadmill. I tried feeding it squid but it wasn’t interested.”

Johnston showed it to the captain and other crew, but he said they were too tired and focused on getting their work done to pay much attention.

After a short while the two-headed pup died, Johnston said. He snapped the photos shown here, then threw it back in the sea.

“I didn’t think it was that special but apparently it is,” Johnston said. “It looked like it had one dorsal fin and one umbilical cord. It had teeth like normal pups.”

Johnston explained that the reason the fishermen cut open pregnant sharks was because they were only allowed to keep 20 blue sharks on a boat at a time, apparently including fetal ones. He indicated that the fins had to remain on the bodies, to prevent the finning that is driving down shark numbers around the globe. “We used all parts of the sharks we caught,” Johnston added.

“Normally when we cut open a pregnant blue shark there could be almost a hundred pups in there,” said Johnston. “We toss them in the water and they usually swim off fine.”

“I cut open quite a few and that was the only strange one I ever saw,” he added.

“Like Live Bait”

“Baby sharks have a very low chance of surviving, and so a two-headed shark that can’t swim properly would be like live bait [if it were to be born],” said Johnston.

C. Michael Wagner of Michigan State University recently confirmed to us that two-headed animals rarely survive in the wild.

As for Johnston, these days he lives in Dubai, where he leads private recreational fishing trips for royals. “I’ve done crab fishing, longlining, I’ve always been fishing,” Johnston said.

He originally hails from Perth, Australia, although his family moved him to the Middle East when he was four years old. “My dad was a fisherman and he came to work in the Saudi prawn fisheries. Except for going back to Australia to visit family or study I’ve been here ever since.”

What Does it Mean?

As to the reader comments that asked if such two-headed creatures could be traced to pollution, radiation, or other environmental ills, Wagner had told us that it is very difficult to pin abnormalities on a single cause. Sometimes the problems also arise spontaneously, an imperfect expression of life’s machinery.

At the least, they are another example of the diversity and complexity that surrounds us.

Two-headed blue shark top

Top view of the two-headed blue shark caught off Australia. Photograph by Christopher Johnston

Two-headed blue shark

Another view of the unfortunate fish. Photograph by Christopher Johnston

 

Brian Clark Howard covers the environment for National Geographic. He previously served as an editor for TheDailyGreen.com and E/The Environmental Magazine, and has written for Popular Science, TheAtlantic.com, FastCompany.com, PopularMechanics.com, Yahoo!, MSN, and elsewhere. He is the co-author of six books, including Geothermal HVACGreen LightingBuild Your Own Small Wind Power System, and Rock Your Ugly Christmas Sweater.

Comments

  1. Baishakhi Mazumdar
    Kalna,Burdwan,W.B
    April 2, 9:35 pm

    Amazing

  2. runt
    January 17, 3:20 pm

    weird

  3. Colt
    Byers,Colorado
    October 8, 2013, 5:15 pm

    its funny how people get offended by almost any thing now there just sharks nothing to worry about beside well destroy our selves any way then the earth will have none of us humans left we are a virus to this planet.

  4. Emma
    Kansas
    September 6, 2013, 3:44 pm

    Out of the 20, he should have kept this one and submitted it to a local marine biology clinic so that it could have been analyzed more.

  5. Courtney
    Moncton NB
    August 1, 2013, 6:21 pm

    I’m confused… The way a certain peice was written- (the part about cutting open the pregnant bellys of sharks because they are legally not supposed to catch more than 20 sharks)- it’s written as though he’s doing the pups a favor and releasing them to sea… But how do these fisherman know whether the fetuses are completely developed? If he finds a pregnant mother to be carrying up to 100 pups, how can they ensure they’re not killing 100 more aside from the 20 they have? He says most seem to “swim off fine” but what if they all die within 20 minutes? If they know a female to be pregnant why not just release the pregnant mother? Perhaps I’m misunderstanding this, but it seems unethical and extremely cruel… If someone has more insight on this; feel free to post and enlighten me. Thanks.

  6. animal activist
    ontario
    July 31, 2013, 2:47 am

    People are sick and cruel for any purpose – fooling with nature and killing for money is not humane!
    Birth defects in any species are not normal but happen – but we as a species are polluting this planet! May karma payback all those who are cruel and may all those poor defenseless creatures have peace and not suffer…..

  7. Nick
    Boston, Mass.
    July 16, 2013, 12:47 pm

    Um….why are these photos “cool”? Is it normal (though unusual) for sharks to be born two-headed, or is this caused by we humans, polluting and screwing up the oceans? Three eyed fish may be funny in “The Simpsons”, but these photos go beyond “cool” and “amazing……don’t they?

  8. Marina Shane
    Canada
    June 27, 2013, 8:23 pm

    WOW! Amazing photos! That is just amazing hat those things can happen! so cool…
    ~Marina Shane

  9. Nabin Dhital
    Nepal
    April 15, 2013, 10:29 pm

    Such amaizing scenes are rare to see..so thanks to the photographers

  10. Glen
    in bed
    April 12, 2013, 4:37 pm

    GIGGITY

  11. Mubarak
    MALE'
    April 12, 2013, 12:02 am

    Poor shark……..