- Any port in a storm, right?
The oceans are full of strange creatures. For example, look no further than the remora.
Remoras are shark-like fish with a unique suction cup-shaped back fin. With that fin, they can attach themselves to the stomachs of larger fish.
Doing so, they can hitch a ride with the bigger, scarier ocean dweller. As they do so, they snack on parasites and smaller fish bothering their host.
It’s a win-win solution, right? Well, new sightings have shown that remoras aren’t always so beneficial to their hosts.
That’s particularly the case with manta rays. A diver recently spotted a remora seeking refuge from a manta ray – by crawling up its butthole.
Since then, reviews of previous observations have indicated that remoras find shelter within rays’ nether regions disturbingly often. Not that often, but still too often for comfort.
What’s a Remora?
Before diving deeper into a manta’s rear, let’s take a more detailed look at what a remora is. They are also called hitchhiker fish, suckerfish, or sharksuckers, all due to their habits of sucking onto other fish.
They don’t achieve the suction with their mouths, though. Instead, remoras have bizarre, ultra-specialized dorsal or back fins that have evolved into suction cups.
A remora can swim under a larger fish and press its dorsal fin on the bigger fish’s stomach. Then, by slowing its swimming speed, the grooves on the fin suction onto the other fish, and it takes the remora for a ride. If the remora wants to detach, a quick dash forward will slide the suction cup free.
Remoras can swim perfectly well on their own, but hitching a ride gives them several benefits. They won’t have to waste their own energy to swim, and they gain the protection of the bigger fish.
In return, they typically offer some kind of cleaning service to their host. They might remove parasites from the host’s skin or dispose of its poop by consuming the waste.
Gross, but efficient.
Remoras aren’t picky about what they attach to, as they’ve been seen suctioning onto boats and divers. Preferably, however, they look for something like big sharks or perhaps manta rays.
Rare Butt Fish
Remoras might not always seek refuge under the host’s stomach or fins, though. A recent observation shows that they sometimes want more protection by crawling inside the host’s cloaca.
That is, the all-purpose fish butthole.
According to a new study published in the journal Ecology and Evolution, a free diver swimming near an adult manta ray noticed something odd going on near the giant ray’s nether parts. There was a remora, but it wasn’t looking to suction onto the ray.
Instead, the remora, upon seeing the diver, “quickly inserted itself into the manta ray’s cloacal opening.” In other words, it slithered up the manta’s butt.
The manta, understandably, didn’t like that at all.
“In response to this intrusion, the manta ray briefly shuddered before continuing to swim away with the remora still inside of its cloacal opening,” the study reads.
The remora’s behavior raised multiple questions. Was this just one particular freaky remora? Or do the suckerfish hide in fish orifices regularly?
Uncomfortable Visitors
It turns out that the latter option is the correct one. Reviewing previous research, the marine biologist team found that remoras like to crawl into cloacas shockingly often.
Granted, that’s still not everyday behavior (hopefully). Within a 15-year review period, the researchers discovered seven instances of butthole remoras from all around the world.
Still, that’s seven instances too many if you ask the unwilling host fish. After all, there’s very little they can do about the butthole invader.
They will certainly try to remove the remora, though. Manta rays with a remora up their cloaca have been seen leaping out of the water or rubbing their rears against stone and sand.
After all, having a fish up your behind can’t be comfortable.
Young Fish’s Last Resort
But why are remoras doing this stuff? There’s no clear answer, but the behavior indicates that remoras likely aren’t always as mutually beneficial to their hosts as we’ve previously imagined.
What does require pointing out, though, is that all the butt remoras have been young and small. After all, once they get too big, they just won’t physically fit where the underwater sun doesn’t shine.
As such, it may be that young remoras, terrified of getting eaten before they reach adulthood, aren’t very selective about where they hide. If a big, scary diver draws close and the nearest safe hiding spot happens to be a manta ray bunghole, so be it.
Look, we’ve all done something we regret later on when we’re young and inexperienced.
Still, the rarity of the observed cases of butt remoras could indicate that fish cloacas aren’t their favorite hidey holes. Then again, who’s to say this stuff doesn’t happen more often and we simply never see it?
In the end, the researchers conclude that remora-hood is likely a spectrum. Some of them will always be good, mutually beneficial hitchhikers; others are more willing to stick their faces into a manta butt.