12 Reasons Pyrosomes Are My New Favorite Terrifying Sea Creatures

Reason number 11: scientists call them "the unicorns of the sea."

1. They are the Borg of the sea.
Pyrosomes are actually colonies composed of hundreds and sometimes thousands of individuals known (reason 1.5 to love pyrosomes) as zooids. The individuals work in unison to propel the colony through the water.

"If the Borg and the Clone Wars had a baby it would be a pyrosome," the marine biologist Rebecca Helm explains.

One long pyrosomes is actually a collection of thousands of clones, with each individual capable of copying itself and adding to the colony. And unlike members of the Borg, which are mentally connected, pyrosome members are physically connected - actually sharing tissues. And while the Borg live in a big scary ship, pyrosomes are the big scary ship. The whole colony is shaped like a giant thimble with a point on one end and an opening on the other, and in some species this opening can be up to 6 feed (2 meters) wide - large enough to fit a full grown human inside.

2. The individual zooids are joined by a "gelatinous tunic."
So how do individual creatures manage to move in such unison? That would be with the help of a, yes, "gelatinous tunic." It joins them all together into a jelly-like body. Ewwwww. And also: ooooooh.

A close-up of individual members of a pyrosome colony, with the basket-like gut visible. (Image by Stefan Siebert, via Deep Sea News.)

3. They can grow to be up to 60 feet long.
They look, the science journalist Carl Zimmer puts it, like a giant "living wind sock."

4. They belong to a group of ocean-farers known as "pelagic sea squirts."
Pelagic. Sea. Squirts.

5. Scientists refer to them, with only a bit of irony, as "the unicorns of the sea."
They're just so, so weird. Even marine biologists -- people whose job it is to study various deep-sea bizarrenesses -- think so. "Despite their improbable nature," David Bennett puts it, "these horrifying giants, the spawn of the worst movie villains, are actually delicate and fragile. The bizarre unicorns of the sea."

6. They're bioluminescent.
They actually get their names from this feature: "pyro" means "fire" in Greek, and "soma" means "body." Fire! Bodies! Their blue-green light can been seen more than 100 feet away. In 1849, the biologist T.H. Huxley wrote this about the light-emitting creatures:

I have just watched the moon set in all her glory, and looked at those lesser moons, the beautiful Pyrosoma, shining like white-hot cylinders in the water.

And they emit light, furthermore, as a group. As Joseph Jameson-Gould puts it, "Each individual zooid is capable of emitting light, and when one does it, the neighbors do too. Sometimes light from one colony will cause a whole other colony to start lighting up. It's as if they're communicating ... talking ... discussing."

Pyrosomes as Lite Brites (Nick Hobgood via Real Monstrosities)

7. They're "fluffy." Yes, fluffy.
That's how Helm describes them. And one diver described a pyrosome like so: "It felt like an exquisitely soft feather boa."

8. They move by multitasking.
Pyrosomes are filter-feeders -- they eat plankton -- and they do their eating by filtering plankton-rich water in, and then expelling it into the hollow interior of the colony. "The combined force of the water from each zooid being ejected into this cavity and so out of the colony's rear thus propels it along," the biologist David Bennett explains, "in a wonderfully simple coupling of both feeding and movement."

9. Their movement is way more elegant than that of similar animals.
While other creatures -- cephalopods, say -- use jet propulsion, pyrosomes are the only animal to do so fluidly. "Because each member noshes on tiny plankton," Helm notes, "they must constantly suck water in and over their baskets, and constantly blow waste out the hollow center. Thus they are moving at a steady, albeit painfully slow, speed."

Which is even more remarkable, considering that the animal is actually a whole collection of animals.

10. They may help humans cure diseases.
Bioluminescence -- especially the collective version that pyrosomes' zooids engage in -- remains something of a mystery to scientists. But research into pyrosomes, as well as into other creatures capable of luminescing, may bring us to new understandings of cell biology. "A wide variety of laboratory techniques have been developed," David Bennett says, "helping scientists to discover many new phenomena, and aid development of treatments for many diseases."

In 2008, it's worth noting, a team of researchers won the Nobel Prize in chemistry for their work with bioluminescent jellyfish.

11. They're mysterious. 
We simply don't know a lot about these colony-based creatures. "Pyrosomes are like unicorns," Rebecca Helm puts it. "Completely improbable, utterly mysterious."

12. They're terrifying monsters of the deep that are actually totally friendly.
They eat plankton, and they feed through filtration -- so, unlike their doppelgangers in undersea terror, the giant squid, they have no teeth or even tentacles. They do their thing, quietly, serenely. "Pyrosomes look terrifying," Helm says, "but like many giants of the sea, they're actually filter feeders."

Via Carl Zimmer