Two-headed sharks may sound like a figment of the big screen, but they exist—and more are turning up worldwide, scientists say. A few years ago off

Two-Headed Sharks Keep Popping Up—No One Knows Why

submited by
Style Pass
2022-05-20 20:00:05

Two-headed sharks may sound like a figment of the big screen, but they exist—and more are turning up worldwide, scientists say.

A few years ago off Florida, fishermen hauled in a bull shark whose uterus contained a two-headed fetus. In 2008, another fisherman discovered a two-headed blue shark embryo in the Indian Ocean.

And a 2011 study described conjoined twins discovered in blue sharks caught in the Gulf of California and northwestern Mexico. Blue sharks have produced the most recorded two-headed embryos because they carry so many babies—up to 50 at at time, says study leader Felipe Galván-Magaña, of the National Polytechnic Institute in Mexico.

Now, Spanish researchers have identified an embryo of an Atlantic sawtail catshark with two heads, according to a new study in the Journal of Fish Biology. While raising sharks for human-health research in the laboratory, a team noticed the unusual embryo in a see-through shark egg.

The catshark embyro was not your average two-headed beast—it's the first such specimen known from an oviparous shark species, or a shark that lays eggs.

Leave a Comment