Colours or structures that allow an animal to blend with its surroundings to avoid detection by other animals. Camouflage can take the form of matching the background colour, of countershading (darker on top, lighter below, to counteract natural shadows), or of irregular patterns that break up the outline of the animal's body. More elaborate camouflage involves closely resembling a feature of the natural environment, as with the stick insect; this is closely akin to mimicry. Camouflage is also important as a military technique, disguising either equipment, troops, or a position in order to conceal them from an enemy.
In the military context, the three elements which primarily identify an object – shine, shape, and shadow – are altered to make the object difficult to identify. The most common technique is to use disruptive pattern painting, destroying shine and creating false shadows; this works effectively on ships, buildings, aircraft, and vehicles. Concealment of field positions is usually achieved by stretching netting, laced with coloured cloth, straw, branches, and other material, over the object to be concealed so that it blends in with the local terrain. Once a site is camouflaged it then becomes necessary to maintain the pretence – by, for example, changing greenery regularly – and also enforce discipline on any troops in the area so that a carefully-camouflaged spot is not revealed by tracks and footpaths leading to it. In modern warfare, the use of sophisticated electronic techniques such as radar jamming and avoidance may also be considered a form of camouflage.