Now You See Me, Now You Don't

Octopus Camouflage

Fight or flight? These are pretty much the only defence mechanisms humans can use in a dangerous situation. It’s not very impressive when compared to those of other organisms, like octopuses, who have other jaw dropping abilities at their disposal. Octopuses are usually seen as the organism with eight tentacles, a culinary delicacy in some places that has the ability to “predict” and identify the soon-to-be victorious football team in world cup matches. But its abilities extend much further than that. These intelligent cephalopods, like squids and cuttlefish, are masters of camouflage. They are so good at it that they put chameleons to shame. They can change not only the colour of their bodies but also the texture, when they are threatened. This ability, like an invisibility cloak, hides them so well and so quickly that the predator is just left bewildered and hungry. This disappearing act, far superior to that of any magician's, is one of the octopuses’ defence mechanisms.  So what is the secret behind this trick? The skins of octopuses have several thousand sac-like cells called chromatophores. These cells are filled with various coloured pigments. When the chromatophores are stretched or expanded, their colour becomes visible on the surface of the skin. Controlling these chromatophores bring about a colour change in an octopus. They also have reflective cells called iridophores and leucophores that can lend an iridescent appearance to their skin. To modify the texture of their skin, they change the size or height of muscular projections on the skin called papillae. How these octopuses perceive colour is still a mystery because lab tests have shown that they are colour blind. The varied colours of the ocean and it’s organisms are just shades of grey to them. It is believed that they might “see” with their skin as it contains light and colour sensing cells. And if all this doesn’t discourage the predator, the octopus has more tricks up its sleeve.  The mimic octopuses alter the position of their legs, shape of their bodies and their movement to imitate venomous and more dangerous creatures in the ocean like sea snakes and lionfish. This change in appearance successfully scares off predators, leaving the octopus unharmed. If none of these tricks work, the octopus resorts to squirting ink and swimming away swiftly. These eight–legged creatures and their magical acts can captivate any audience and receive standing ovations every time.