The Sex Lives Of Ghost Sharks Are Weirder Than You Think

A shortnose chimaera from the Gulf of Mexico. NOAA

The sex life of the ghost shark is one of those phrases that will immediately get anyone’s attention. Now that we have, we should probably explain what a ghost shark actually is.

As you might have guessed, it is not a real ghost – and rather deceptively, it’s not technically a shark either. Known primarily as chimaeras, they have also been called rat fish, pseudo-spookfish, and rabbit fish. That’s right: they’re not rabbits nor rats. It would be most accurate to describe them as most closely related to sharks, but their lineage split from their teethy brethren 400 million years ago.

Today, they live in the deepest of waters, defend themselves with venomous spines, detect their prey using electrical currents, and use their three pairs of massive grinding tooth plates to chow down on whatever fishy food they can get their proverbial hands on. As reported by a recent study in the Journal of Fish Biology, they also have very strange sex lives.

A team led by the Victoria University of Wellington managed to get their hands on a good number of Chimaera carophila and Hydrolagus homonycteris ghost sharks that had been accidentally caught by fishing trawlers over the last two years. Caught between 400 and 1,300 meters (1,312 and 4,265 feet), the team note that it’s very rare that they’re spotted at depths that “shallow”.

The team decided to scientifically observe and probe them, and found out that the fact that they have retractable sexual organs on their heads wasn’t the oddest thing about them.

A rare sighting of a ghost shark caught on camera. CNN via YouTube

According to the team, the comparatively lengthier females have in-built sperm storage banks. The conditions within are so amiable to sperm that they can happily swim around in there for at least three years and still remain viable. As mates are hard to come across in the deep and dark oceanic depths, this method of sperm storage may be vital for their species’ survival.

Yes, okay – that retractable sex organ thing has piqued your interest hasn’t it? According to National Geographic, the male’s sex pole has hooks on it, which grab onto the female’s fins and pelvis. The lead author of the new study describes mating as “not… very pleasant” for the latter partners.

The team were also interested in the ghost fishes’ diet, but in order to find this out, they had to do something rather gross.

“Guts were removed and dissected. Contents of guts were rinsed with water into a Petri dish.” they write in their study. “A fragmented prey count was based on the number of eyes, heads, mouth parts, tails… or other anatomical parts traceable to a single specimen.”

It turns out they have a penchant for barnacles. The more you know, right?

[H/T: National Geographic]

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