Researchers have revealed some of the secrets behind the cuttlefish's incredible 3D camouflage ability. These cephalopods evidently share some of its unique abilities with other creatures such as squids and even bivalves.
Now You See Me, Now You Don't
Anyone that has seen the camouflage ability of cuttlefish and other cephalopods will agree that their skill is quite extraordinary. In fact, the researchers have even described their ability as akin to removing an invisibility cloak when they drop the disguise and suddenly appear seemingly out of nowhere.
In the past, it has been known that the color changing ability of some cephalopods can be attributed to chromatophores, which are miniscule muscular organs that allow the creatures to change color at will in response to a signal from the brain.
However, cuttlefish also possess the ability, not just to change colors, but also to change the texture of their skin in less than a second. This allows the creatures to seamlessly disguise themselves as nearby objects of different textures such as sand, algae, kelp, or corals. For quite a long time, the mechanisms behind this ability have been a mystery, but now a team of researchers from the University of Cambridge and the Marine Biological Laboratory has finally revealed their secrets — or at least some of it.
A Real 'Catch'
Working with chromatophores is a second muscular group called the papillae, which allow the creatures' skin to create bumps and lumps. In the same way that chromatophores individually change color, each papilla can change its texture to blend in with the nearby environment.
Researchers have now found that the circuit by which the papillae are activated runs similar to the way squids control the iridescence of their skin using iridophores. Interestingly, cuttlefish cannot control their iridescence the way that squids can while squids do not have papillae, so the find suggests a bit of an evolutionary overlap between the two creatures.
Furthermore, researchers also explored how the cuttlefish is able to hold the new shape in place for over an hour without using neural signals, and found that they use a "catch" mechanism similar to how mussels, oysters, and other bivalves keep their shells shut without using too much energy and effort. Simply put, the papillae's "new" texture is essentially locked into position until the cuttlefish signals its release.
More New Questions For The Cuttlefish
Naturally, there are still many things to discover about the cuttlefish's unique 3D ability. For instance, from an evolutionary point of view, researchers question whether the common ancestor of the cuttlefish and squid was able to express iridescence, camouflage with papillae, or possibly even both.
Moreover, the big question of how the creature interprets its surroundings to practically change itself into it still remains unclear. Perhaps if there is one thing for sure, it is that the cuttlefish's 3D camouflage ability is quite special.
"The sea is full of strange and wondrous creatures, but there are few as bizarre and intelligent as octopuses and cuttlefish," said Dr. Trevor Wardill of the University of Cambridge.
The study is published in iScience.