You have seen it in war films; soldiers with painted faces, branches attached to their helmets, tanks similarly bedecked with branches, and uniforms with undulating designs in tones of brown and green. In recent times the soldiers that we have watched so often on television have been wearing beige uniforms rather than these brown and green ones, because this time they have been fighting not in forested mountainous regions but in desert. This method of concealment used by armies is actually nothing but imitation of a technique used by animals in their struggle for survival. Underwater creatures use many defence mechanisms. Some rely on speed and agility to escape their predators. Others which move slowly have armoured shells. Some have a strange menacing appearance that scares off enemies, and others poisonous quills. Camouflage is another effective defence weapon, making the creature almost invisible or confusing predators. At the same time it allows the creature to hunt without alerting its own prey to its presence.

Combined with the ability of many animals to remain motionless for a long time, camouflage is a strategy that serves well in both defence and attack. Big fish eat little fish... if they can see them. Among the most astonishing of Mediterranean fish is the broad-nosed pipefish (Syngnathus typhle), which looks more like a reptile, with its long body and head, and pipe-shaped mouth. The pipefish changes colour to blend in with the background. It lives in rocky places amongst seaweed and sea grass, where it is virtually invisible. Since it is a slow mover and cannot escape its enemies once spotted, it lies motionless in the sea grass until the danger has passed. Its skin takes on the green colour and pattern of the sea grass, and it lifts its head and remains as still as a statue. The same technique makes the pipefish a dangerous hunter. Lacking the speed of movement to chase its prey, it lies in wait until unsuspecting smaller fish come within reach.

The greatest masters of camouflage in the Mediterranean are the members of the Scorpaenidae family of fish, particularly scorpion fish and rockfish. Rockfish mainly live on the seabed amongst rocks where sunlight does not penetrate, and are very difficult to detect. The small types are more poisonous than their larger relatives. They lie motionless on the bottom for most of the time, waiting for prey to approach, and change colour to become almost invisible. Fish are the first creatures which come to mind when we think of the sea, but there are many other kinds of marine animals which make use of camouflage. The octopus is one of the most cunning sea creatures, and an expert at camouflage. It uses three different camouflage techniques: colour, pattern and mimicry. The pigment cells known as chromatophores in the octopus' skin takes on both the colour and pattern of the background. The skin colour also reflects the octop'sun emotional state at any moment, turning white when it is afraid and red when it is angry.