Cuttlefish are known as masters of camouflage because they can change skin colours and textures in an instant to blend into the surrounding environment. They do it so well, it is almost impossible to believe that these animals themselves are colour-blind.
Kings of Camouflage © Civil Digital
Cephalopods have huge eyes, and much of their brain is dedicated to processing visual information. They use this information to control their disguises through a dense network of nerves running from the brain to the skin.
Using unique skin pigment cells, cuttlefish can rapidly change their skin colour and pattern to blend in with the background. The skin layers can swell and contract, changing the reflected colours. At the same time, the cuttlefish can also control millions of pigment-filled organs to add patterns to their skin.
Cephalopods do not just mimic the colours of the sea floor or coral reefs. Sometimes, they make their arms flat and crinkled and wave them like seaweed. They can also take on the shape of a rock and slowly move by following currents on the sea floor.
Surprisingly, the colour-sensing cells in the retinas of cuttlefish eyes are composed of only one type of cone cell. Humans have three different types, each sensitive to a different colour of light, enabling us to differentiate between different colours. Scientists were astonished to discover that cuttlefish are in fact colour-blind.
So it seems that cuttlefish camouflage themselves by matching contrasts through light intensities of objects rather than their colours.
Supporting this theory, scientists have used night-vision video to discover that cuttlefish even match their background at night. How these animals match their environments so accurately is still a mystery.
Cuttlefish can also use camouflage to deceive other cuttlefish. A male cuttlefish will typically guard several females from other challengers. He does not often have physical fights. It is enough for him to put on a powerful visual display.
But if another male disguises himself to look female, through changes of the skin and hiding two of their arms, he can sneak up to the guarded female and mate. The sneaky male’s disguise may be so good that the other male may try to guard him as part of his harem.