When you witness a cuttlefish vanish for the first time, your brain is unable to comprehend what your eyes have just witnessed. An animal’s fins ripple like a tiny skirt as it hovers over the sand. Then all that’s left is sand. Nothing, not even a puff of ink or movement. It’s just the seafloor, exactly as it was a moment ago, but something is breathing inside of it now.
After filming this trick hundreds of times, Roger Hanlon, a marine biologist at Woods Hole who has spent his entire life pursuing these creatures, still discusses it the way most people discuss a magician they don’t understand. When an octopus first startled him during a snorkeling excursion when he was twenty-one, he seemed to be permanently hooked. Watching his footage gives the impression that he is still attempting to make sense of something that defies explanation.
| Category | Details |
|---|---|
| Common Name | Cuttlefish |
| Scientific Class | Cephalopoda (alongside octopus and squid) |
| Average Length | Around 10 inches (25 cm); Australian giant cuttlefish reaches twice that |
| Number of Arms | Ten — two specialized for capturing prey |
| Hearts | Three, pumping blue-green blood |
| Habitat | Shallow tropical and temperate waters; not native to the Americas |
| Diet | Crab, fish, shrimp, mollusks, occasionally other cuttlefish |
| Lifespan | Roughly 1 to 2 years |
| Key Feature | Cuttlebone — internal shell controlling buoyancy |
| Known Species | Over 100 worldwide |
The first small joke their name plays on you is that cuttlefish aren’t fish. They are soft-bodied, boneless mollusks with the exception of their peculiar internal shell, the cuttlebone, which they use similarly to a submarine’s ballast tank. They share the unsettling intelligence of the cephalopods, the same family that includes squid and octopuses. A brain shaped like a doughnut. Three hearts. blood that is blue-green. The kind of biology that you would likely refer to as lazy worldbuilding if you came across it in fiction.
But it’s not their anatomy that makes them exceptional. The skin is the problem. In a split second, their skin can change color, pattern, and even texture, smoothing flat to resemble sand and pushing up bumps to resemble coral. According to Hanlon, the layered system of pigment cells is made up of tiny, muscular sacs that pull open to reveal colors like yellow, red, or brown before snapping shut once more. Reflective cells that produce blues and greens are located beneath those. In essence, it’s plumbing, but it’s plumbing at the speed of thought.
The broadclub cuttlefish found in Indonesian waters was once compared to a tiny alien spacecraft and a pair of eyes peering from seaweed by Mark Norman, a researcher at Museum Victoria in Australia. It’s an accurate description. It is truly disorienting to watch one transition from camouflage to a hypnotic, pulsing light show intended to stun prey. The animal appears to be using two conflicting tactics at once: hiding flawlessly and then becoming unavoidable.
Researchers still have a lot of unanswered questions. Since cuttlefish are technically colorblind, it is nearly impossible to explain their ability to match colors mathematically. It’s possible that they are reading light through their skin. No one is certain. It’s the kind of mystery that is difficult to solve in a single paper and is unlikely to be resolved anytime soon.
It’s difficult to ignore the fact that we frequently assume intelligence takes on a recognizable form, such as a face or hands. Silently, the cuttlefish continues to insist otherwise. You begin to wonder how much of the ocean is observing us in ways we haven’t bothered to notice yet when you watch one solve a puzzle or alter its skin to match a checkerboard a bored scientist created just to test its limits.
