Absurd Creature of the Week: 10-Foot Bobbit Worm Is the Ocean’s Most Disturbing Predator

ORIGINAL: Wired

By Matt Simon
09.06.13

Image: Wikimedia

If I could go back to my childhood I would have never waited for rainstorms to flush out all of the earthworms for me to grab, place on leaves, and send down the flooded gutters into the sewers. I thought it was a funny race. But now I wish I could take it all back. Because in tropical oceans there exists a worm that could violently avenge its relatives.

This is Eunice aphroditois, also known as the bobbit worm, a mix between the Mongolian death worm, the Graboids from Tremors, the Bugs from Starship Troopers, and a rainbow — but it’s a really dangerous rainbow, like in Mario Kart. And it hunts in pretty much the most nightmarish way imaginable, digging itself into the sea floor, exposing a few inches of its body — which can grow to 10 feet long — and waiting.

Using five antennae, the bobbit worm senses passing prey, snapping down on them with supremely muscled mouth parts, called a pharynx. It does this with such speed and strength that it can split a fish in two. And that, quite frankly, would be a merciful exit. If you survive initially, you get to find out what it’s like to be yanked into the worm’s burrow and into untold nightmares.

A mix between the Mongolian death worm, the Graboids from Tremors, the Bugs from Starship Troopers, and a rainbow.

“What happens next is rather unknown, especially because they have not been observed directly,” Luis F. Carrera-Parra and Sergio I. Salazar-Vallejo, ecologists specializing in annelid polychaetes at El Colegio de la Frontera Sur (ECOSUR) in Campeche, Mexico, wrote in a joint email to WIRED. “We think that the eunicid injects some narcotizing or killing toxin in their prey animal, such that it can be safely ingested — especially if they are larger than the worm — and then digested through the gut.”

Before we go any further, let’s just go ahead and get this out of the way. The bobbit worm may or may not be named after John Bobbitt, whose misadventures won’t be elaborated on here. The story goes that an underwater photographer saw the worm’s powers of … amputation as being analogous to those of John’s wife Lorena. But according to Anja Schulze, a marine biologist at Texas A&M University at Galveston, the origin of the name is far from clear.

In fact, scientists can’t seem to agree on how to even classify the thing. “We might actually have not just different species, but different genera of these worms,” Schulze said. “The color patterns can vary quite a bit, and we really don’t know how many species it refers to.” Complicating matters is the preservation process. According to Schulze, pickled specimens available to scientists have been soaking in formalin or ethanol, which leaches out their gorgeous iridescent color.

And marine biologists don’t come across bobbit worms too often in the wild, Schulze says. But every once in a while one just appears in an aquarium, like a kraken, ready to make a mess of things, as if Liam Neeson himself ordered it into existence. Indeed, it has become the bane of many an aquarist. When folks introduce live rocks — which are actually skeletons of dead coral — into their saltwater aquariums, a teeny-tiny bobbit worm can come along for the ride. But they don’t stay small for long.

Bobbit worms can tuck themselves away among coral and decimate an aquarium, picking off fish one by one, which you can imagine is quite confusing for the owner, since contrary to the events in Finding Nemo, fish typically don’t just disappear. And they can even take the pros by surprise. When a public aquarium in England was having a problem with mysteriously maimed fish and even corals, they set out bait night after night, which disappeared, hooks and all. Staffers eventually had to dismantle the exhibit, finding a 4-foot bobbit worm named Barry (presumably they gave him this name — he probably hadn’t always gone by Barry).

A Daily Mail story about Barry suggested that the bobbit worm can permanently paralyze human appendages with its bristles, though Carrera-Parra and Salazar-Vallejo question this. They say a different family of worms, the fireworms, have harpoon-shaped chaetae — bristles of sorts — that release a toxin that can cause severe skin irritation, but bobbit worms “do not have abundant chaetae and their chaetae are not used for defensive purposes, but for improving traction for crawling over the sediment or inside their galleries or tubes.”

And as for reproduction, the bobbit worm’s habits remain a mystery. But Carrera-Parra and Salazar-Vallejo look to the somewhat troubling rituals of its relatives for insight into what could be going on. Gentlemen, take it away.

“Some eunicid polychaetes have an impressive transformation of their body for reproduction. The posterior part of their bodies are modified to contain sperm or oocytes and often have a large eyespot. During a very short period of time, depending on the season and under the influence of a certain phase of the moon, these posterior regions, or even the whole body, leave their shelter and swim en masse to the surface of the sea. This swarming behavior concludes with the massive release of sperm and eggs such that fecundation can be done.”

Hate to leave you with the image of a beautiful tropical ocean swarming with sex-crazed 10-foot-long worms with hair-trigger jaws, but that’s totally happening now.