An undescribed species of squid, filmed almost 13,450 feet (4,100 meters) down in the Pacific, buried nearly its entire body upside down in the mud and left only its siphon and two stiff tentacles poking above the sediment, arranged to look exactly like the glass sponges growing around it.
The sighting
The animal turned up on camera during a survey of the Clarion-Clipperton Zone, a stretch of abyssal seafloor between Hawaii and Mexico, run by a remotely operated vehicle as part of the UK-led SMARTEX project. The squid had inverted itself into the mud so that only its siphon, the muscular nozzle it uses to jet through water, and two long tentacles were visible. Real glass sponges nearby, tube-shaped and mounted on stalks, sat close enough that the squid’s exposed parts read as one more sponge among several. Nothing about the frame looked staged. It looked like seafloor furniture.
Who found it, and where it’s published
The find is described in a paper led by Alejandra Mejía-Saenz of the Scottish Association for Marine Science, with Bethany Fleming of the University of Southampton and the National Oceanography Centre as co-author, published November 25 in the journal Ecology. The paper reports the squid holding both tentacles rigid and upright above the mud line, positioned to resemble either sponge stalks or the tubes built by polychaete worms. The authors identify the animal as a whiplash squid, family Mastigoteuthidae, not yet assigned a species name.
How the disguise actually works
The squid flips itself and packs its mantle and arms down into the sediment, leaving the siphon exposed, the paper’s authors propose, so it can keep pumping water over its gills while the rest of it stays hidden. Holding two tentacles rigid and upright for any length of time takes sustained muscular effort that most soft-bodied cephalopods don’t bother with. It isn’t collapse or drift; it’s a held posture, and a specific one, matched to the exact shapes sitting next to it. Other cephalopods already bury themselves by different means: cuttlefish pump water from their funnel into the seabed and let particles settle over them, a process called fluidization, while bobtail squid beat their arms fast enough to pile sediment over their own bodies, called fanning. This whiplash squid’s method, upside down with two limbs held out as landmarks, matches neither.
What the disguise might be for
The researchers propose two possible functions, and they’re careful to call both proposals, not conclusions. One is masquerade: looking like a sponge to slip past predators that hunt by sight or sonar, such as beaked whales. The other is a lure: mimicking a sponge’s stalks closely enough that passing crustaceans, the squid’s likely prey, mistake them for feeding structures and drift within reach. Either theory fits how the abyssal plain runs its economy. Food down there is scarce, and staying motionless while impersonating a piece of the scenery costs far less energy than swimming and chasing. Jim Barry of the Monterey Bay Aquarium Research Institute, who wasn’t involved in the study, pointed out that the trick resembles camouflage already documented in sponges, soft corals, and polychaete worms themselves, which raises the possibility that copying a stationary invertebrate is a far more common deep-sea strategy than anyone had catalogued.
The myth this kills
Burial camouflage in cephalopods wasn’t new science. Certain octopuses, cuttlefish, and coastal squid species are documented burying themselves almost instantly when threatened, and the behavior had always been read as a shallow-water trick, built for animals living under bright, visually hunted reefs and sandbanks. This sighting breaks that assumption twice over: it is the first time any deep-sea squid has been recorded burying itself at all, and the first time any cephalopod, anywhere, has been recorded doing it upside down.
What nobody knows yet
The squid still has no species name; it remains formally undescribed. Whether the burying was a deliberate act or the animal had simply settled into a burrow is genuinely unresolved in the paper. So is the choice between the predator-avoidance and prey-luring explanations, since only one encounter exists. How rare this kind of sighting is shows in the numbers: across roughly 3,100 miles (5,000 kilometers) of ROV survey track in the Clarion-Clipperton Zone, the team logged just 33 cephalopod encounters total, and this was only the second squid seen at this site in more than 40 years of research there. Since seabed image surveys of the Northeast Pacific abyss began in the late 1970s, only four cephalopod taxa have ever been reported from it. That scarcity cuts both ways: it means this behavior is a rare capture, and it means the same behavior is very likely happening far more often than any camera will ever catch.
The moment Fleming almost missed it
Bethany Fleming was reviewing ROV footage when she noticed two thin white filaments on the seafloor, the kind of detail that could easily be logged as tube worms and scrolled past. She recalled wondering, essentially, whether there was actually a squid under there at all. The team only confirmed a living animal once it moved, breaking its own disguise on camera. That half-second of doubt is the only reason this behavior exists in the scientific record at all; a slightly faster scroll, and the footage would have gone down as one more sponge.