About Camouflage

This is the most common form of camouflage, found to some extent in the majority of species. The simplest way is for an animal to be of a colour similar to its surroundings. Examples include the "earth tones" of deer, squirrels, or moles (to match trees or dirt), or the combination of blue skin and white underbelly of sharks via countershading (which makes them difficult to detect from both above and below). More complex patterns can be seen in animals such as flounder, moths, and frogs, among many others. Some forms of camouflage use contrasting shades to break up the visual outline, as on a gull or zebra.

Beyond colours, skin patterns are often helpful in camouflage as well. This can be seen in common domestic pets such as tabby cats, but striping overall in other animals such as tigers and zebras help them blend into their environment, the jungle and the grasslands respectively. The latter two provide an interesting example, as one's initial impression might be that their coloration does not match their surroundings at all, but tigers' prey are usually colour blind to a certain extent such that they cannot tell the difference between orange and green, and zebras' main predators, lions, are colour blind. In the case of zebras, the stripes also blend together so that a herd of zebras looks like one large mass, making it difficult for a lion to pick out any individual zebra. This same concept is used by many striped fish species as well. Among birds, the white "chinstraps" of Canada geese make a flock in tall grass appear more like sticks and less like birds' heads.

Mimicry describes a situation where one organism, the mimic, has evolved to share common outward characteristics with another organism, the model, through the selective action of a signal-receiver. The model is usually another species, or less commonly, the mimic's own species, including automimicry, where one part of the body bears superficial similarity to another. The signal-receiver is typically another intermediate organism, e.g. the common predator of two species, but may actually be the model itself. As an interaction, mimicry is always advantageous to the mimic and harmful to the receiver, but may either increase or reduce the fitness of the model. The distinction between mimicry and camouflage is arbitrarily defined in that the model in camouflage is not another organism; the arbitrary nature of this distinction between the two phenomena can be seen by considering animals that resemble twigs, bark, leaves or flowers, in that they are often classified as camouflaged (a plant does constitute the "surroundings"), but sometimes classified as mimics (a plant is also an organism). The more general category that encompasses such examples, therefore, is crypsis.

Camouflage was not in wide use in early western civilisation based warfare. 19th century armies tended to use bright colours and bold, impressive designs. These were intended to daunt the enemy, attract recruits, foster unit cohesion, or allow easier identification of units in the fog of war.
Smaller, irregular units of scouts in the 18th century were the first to adopt colours in drab shades of brown and green. Major armies retained their colour until convinced otherwise. The British in India in 1857 were forced by casualties to dye their red tunics to neutral tones, initially a muddy tan called khaki (from the Urdu word for 'dusty'). White tropical uniforms were dyed by the simple expedient of soaking them in tea.