Increased sightings of two-headed sharks baffle scientists

Before you go, we thought you'd like these...
Before you go close icon

Two-headed sharks may seem like science fiction, but National Geographic is pointing out that they seem to be becoming more common around the world.

As the report notes, past discoveries include two-headed pre-term sharks found off the Florida coast and in the Indian Ocean as well as two sets of conjoined twins found around Mexico.

Scientists in Spain have also announced that one of their lab shark embryos was growing two heads which is one of the first known instances of the phenomenon appearing in an egg-laying member of the species.

SEE EARLIER: Scientists stunned to find bizarre two-headed shark

As the team states in the resulting study, "Each head had a mouth, two eyes, a brain, a notochord [like a spinal cord], and five gill openings on each side."

They also identified separate hearts, stomachs, and livers but one set of shared intestines, kidneys, and reproductive system.

While researchers don't exactly know why these mutations are happening, occurrences in the wild have been attributed to infections, pollution, and overfishing causing the gene pool to shrink.

A recent BBC report also describes past accounts of two-headed dolphins, snakes, and turtles.

Related: Would you ever sleep with sharks?

7 PHOTOS
Sleeping with sharks in Paris aquarium
See Gallery
Sleeping with sharks in Paris aquarium
A view shows an underwater room structure installed in the Aquarium of Paris, France, March 14, 2016. Airbnb and the Aquarium of Paris offer contest winners a night underwater sleeping with sharks and create a research platform for "misunderstood" shark species. Picture taken March 14, 2016. REUTERS/Charles Platiau
A diver takes pictures as people look at sharks from an underwater room structure installed in the Aquarium of Paris, France, March 14, 2016. Airbnb and the Aquarium of Paris offer contest winners a night underwater sleeping with sharks and create a research platform for "misunderstood" shark species. Picture taken March 14, 2016. REUTERS/Charles Platiau
A diver takes pictures as people look at sharks from an underwater room structure installed in the Aquarium of Paris, France, March 14, 2016. Airbnb and the Aquarium of Paris offer contest winners a night underwater sleeping with sharks and create a research platform for "misunderstood" shark species. Picture taken March 14, 2016. REUTERS/Charles Platiau TPX IMAGES OF THE DAY
People look at sharks from an underwater room structure installed in the Aquarium of Paris, France, March 14, 2016. Airbnb and the Aquarium of Paris offer contest winners a night underwater sleeping with sharks and create a research platform for "misunderstood" shark species. Picture taken March 14, 2016. REUTERS/Charles Platiau
A diver takes pictures as people look at sharks from an underwater room structure installed in the Aquarium of Paris, France, March 14, 2016. Airbnb and the Aquarium of Paris offer contest winners a night underwater sleeping with sharks and create a research platform for "misunderstood" shark species. Picture taken March 14, 2016. REUTERS/Charles Platiau
People look at sharks from an underwater room structure installed in the Aquarium of Paris, France, March 14, 2016. Airbnb and the Aquarium of Paris offer contest winners a night underwater sleeping with sharks and create a research platform for "misunderstood" shark species. Picture taken March 14, 2016. REUTERS/Charles Platiau
of
SEE ALL
BACK TO SLIDE
SHOW CAPTION +
HIDE CAPTION

Read Full Story

Sign up for Breaking News by AOL to get the latest breaking news alerts and updates delivered straight to your inbox.

Subscribe to our other newsletters

Emails may offer personalized content or ads. Learn more. You may unsubscribe any time.

From Our Partners