(CN) — The cuttlefish, known for its mesmerizing camouflage, has impressed scientists by revealing that it has yet another unique trick up its sleeve.
Dubbed the “passing-stripe” display by researchers, dark stripes have been recorded moving downward across the head and arms of hunting cuttlefish, a novel form of motion camouflage. Unsuspecting prey, such as small crabs, are caught off guard by the patterned exhibition and quickly become the cuttlefish’s dinner.
Researchers working on the study, based at the University of Bristol, aimed to discover how cuttlefish in particular navigate the disruption of camouflage by motion, as the advantages of camouflage are typically negated when a predator begins to move in a hunt. It turns out the cuttlefish is among a small sect of special animals that use motion camouflage, a special form of disguise that combines — you guessed it — motion with camouflage to make the predator even more invisible.
Dragonflies and falcons have been known to fly in a manner that tricks their prey’s visual system and seemingly makes them invisible, while snakes, stick insects and even some spiders have been recorded swaying with the movement of vegetation to blend in during a hunt.
Head researcher Matteo Santon proposed that the cuttlefish’s advanced camouflage skills, which include the use of chromatophore pigment cells to create dynamic color changes and unpredictable movements, are likely used in a similar manner when a cuttlefish is hunting prey.
Santon, a marine scientist, first tested the efficacy of motion camouflage on potential cuttlefish prey. Shore crabs were tethered to a Styrofoam treadmill sitting before a monitor, which played various moving stripe patterns both similar to and dissimilar to the patterns cuttlefish display.
The crabs reacted much more strongly to high-contrast patterns and reacted least to stripes moving in a downward direction, the latter of which is a pattern typically displayed by cuttlefish. This suggested that the downward passing stripe display used by cuttlefish is likely an effective strategy to keep the predator undercover when hunting.
Next, Santon and his team put their theory to the test using real cuttlefish. A multicamera rig recorded 17 individual cuttlefish using stripe hunting displays 28 different times. A typical hunt looked like this: a cuttlefish would spot prey, rush toward it and switch to a passing stripe display in the final phases of attack as it approached its dinner.
The passing stripe display seemed to effectively keep the cuttlefish unnoticeable to prey, even in an environment where moving sea water, marine life and other unpredictable factors can make camouflage difficult.
The discovery disputes the common theory that the cuttlefish uses a form of hypnotization to capture its prey; the prey likely just doesn’t even see the cuttlefish, and rather a confusing patterned movement, the researchers say.
“The cuttlefish is using an incredibly sophisticated and unexpected way to camouflage its approaching motion,” Santon said. “Our study contradicts the common belief that the cuttlefish is hypnotizing its prey with the very conspicuous (to our eyes) passing stripe display, by showing that the prey does not even see the predator approaching.”