Camouflage

Camouflage

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Camouflage is a method of concealment that allows an otherwise visible animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

, military vehicle, or other object to remain unnoticed, by blending with its environment. Examples include a leopard
Leopard
The leopard , Panthera pardus, is a member of the Felidae family and the smallest of the four "big cats" in the genus Panthera, the other three being the tiger, lion, and jaguar. The leopard was once distributed across eastern and southern Asia and Africa, from Siberia to South Africa, but its...

's spotted coat, the battledress
Battledress
Battledress, or fatigues in the general sense, is the type of uniform used as combat uniforms, as opposed to 'display' dress or formal uniform worn at parades and functions. It may be either monochrome or in a camouflage pattern...

 of a modern soldier
Soldier
A soldier is a member of the land component of national armed forces; whereas a soldier hired for service in a foreign army would be termed a mercenary...

 and a leaf-mimic butterfly
Butterfly
A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured...

. Camouflage is a form of visual deception; the term probably comes from camouflet, a French
French language
French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...

 term meaning smoke blown in someone's face as a practical joke. Military camouflage
Military camouflage
Military camouflage is one of many means of deceiving an enemy. In practice, it is the application of colour and materials to battledress and military equipment to conceal them from visual observation. The French slang word camouflage came into common English usage during World War I when the...

 is part of a broad area of deception and concealment from all means of detection including sound and radar, and involving non-camouflage techniques such as use of decoys and electronic jamming.

According to Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...

's theory of Natural Selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....

, characteristics such as camouflage that help an animal to survive will tend to evolve in any population.

Camouflage, whether in animals or in military use, can be achieved in several different ways, including the apparent opposites Mimesis - being seen, but resembling something else, and Crypsis - being hidden. In both cases, however, camouflage is achieved not by actual invisibility, but by not being noticed. A third approach, Dazzle, found military application in the 20th century.

Camouflage is not the only form of Animal coloration that helps animals to survive. Other adaptations include Warning coloration
Aposematism
Aposematism , perhaps most commonly known in the context of warning colouration, describes a family of antipredator adaptations where a warning signal is associated with the unprofitability of a prey item to potential predators...

, non-concealing forms of Mimicry (as when a harmless Hoverfly resembles a stinging Wasp), the use of bright colours in Sexual selection
Sexual selection
Sexual selection, a concept introduced by Charles Darwin in his 1859 book On the Origin of Species, is a significant element of his theory of natural selection...

, and the use of pigment
Biological pigment
Biological pigments, also known simply as pigments or biochromes are substances produced by living organisms that have a color resulting from selective color absorption. Biological pigments include plant pigments and flower pigments...

 in the skin to protect against sunburn.


Camouflage by mimesis


In Mimesis, the whole animal (or military equipment) looks like some other object.

Mimesis is common in prey animals, for example when a Peppered Moth
Peppered moth
The peppered moth is a temperate species of night-flying moth. Peppered moth evolution is often used by educators as an example of natural selection.- Distribution :...

 caterpillar mimics a twig, or a grasshopper mimics a dry leaf.

Mimesis is employed by some predators
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...

 (or parasites), luring the prey to approach, for example when a flower mantis
Flower Mantis
Flower Mantis is a common name given to various species of praying mantis that mimic flowers including:*Acromantis formosana *Blepharopsis mendica...

 mimics a particular kind of flower, such as an orchid


Camouflage by crypsis


Crypsis means blending with the background, making the animal (or military equipment) hard to see (or to detect in other ways, such as by sound or scent: for details, see Crypsis
Crypsis
In ecology, crypsis is the ability of an organism to avoid observation or detection by other organisms. It may be either a predation strategy or an antipredator adaptation, and methods include camouflage, nocturnality, subterranean lifestyle, transparency, and mimicry...

). Camouflage - visual crypsis - can be achieved in many different ways, including:
  • General resemblance to background
  • Disruptive patterning
  • Crypsis by behavior
  • Crypsis by changing skin pattern, color
  • Countershading
  • Counterillumination


These ways of achieving crypsis are described below.

General resemblance to background


Some animals' colors and patterns resemble a particular natural background, for example the Peppered Moth
Peppered moth
The peppered moth is a temperate species of night-flying moth. Peppered moth evolution is often used by educators as an example of natural selection.- Distribution :...

 adult blends in with tree bark.

Disruptive patterning


Some animals, whether predators or prey, have disruptive patterns that help to achieve crypsis by breaking up their outlines with strongly-contrasting markings, for example in the Leopard
Leopard
The leopard , Panthera pardus, is a member of the Felidae family and the smallest of the four "big cats" in the genus Panthera, the other three being the tiger, lion, and jaguar. The leopard was once distributed across eastern and southern Asia and Africa, from Siberia to South Africa, but its...

.



Disruptive patterning is now common in military usage, both for uniforms and for military vehicles. Disruptive patterning, however, does not always achieve crypsis on its own, as an animal or a military target may be given away by other factors including shape, shine, and shadow.


Crypsis by behavior


Some animals actively seek to make themselves cryptic, using materials such as twigs, sand, or pieces of shell to conceal their outlines, for example when a Caddis Fly larva builds a decorated case, or when a Decorator Crab decorates its back with seaweed, sponges and stones. Most other forms of crypsis also require some animal behavior, e.g. to keep still, to lie flat, or to sway as if being rippled by wind or water currents.

Similar principles can be applied for military purposes, for example when a Sniper
Sniper
A sniper is a marksman who shoots targets from concealed positions or distances exceeding the capabilities of regular personnel. Snipers typically have specialized training and distinct high-precision rifles....

 wears a Ghillie suit
Ghillie suit
A ghillie suit, wookie suit, yowie suit, or camo tent is a type of camouflage clothing designed to resemble heavy foliage. Typically, it is a net or cloth garment covered in loose strips of cloth or twine, sometimes made to look like leaves and twigs, and optionally augmented with scraps of foliage...

 designed to be further camouflaged by decoration with materials such as tufts of grass from the sniper's immediate environment.


Crypsis by changing skin pattern, colour


Animals such as chameleon
Chameleon
Chameleons are a distinctive and highly specialized clade of lizards. They are distinguished by their parrot-like zygodactylous feet, their separately mobile and stereoscopic eyes, their very long, highly modified, and rapidly extrudable tongues, their swaying gait, the possession by many of a...

, flatfish, squid or octopus
Octopus
The octopus is a cephalopod mollusc of the order Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms...

 actively change their skin patterns and colours using special chromatophore
Chromatophore
Chromatophores are pigment-containing and light-reflecting cells found in amphibians, fish, reptiles, crustaceans, and cephalopods. They are largely responsible for generating skin and eye colour in cold-blooded animals and are generated in the neural crest during embryonic development...

 cells to resemble whatever background they are currently resting on (as well as for signalling). See also :Category:Animals that can change color.

Again, similar principles can be applied for military purposes.


Crypsis by countershading


Countershading uses graded colour to create the illusion of flatness. Shadow makes an animal lightest on top, darkest below; countershading 'paints in' tones darkest on top, lightest below, making the countershaded animal nearly invisible against a matching background., and against a matching background, of invisibility. American artist Abbott Handerson Thayer
Abbott Handerson Thayer
Abbott Handerson Thayer was an American artist, naturalist and teacher. As a painter of portraits, figures, animals and landscapes, he enjoyed a certain prominence during his lifetime, as indicated by the fact that his paintings are part of the most important U.S. art collections...

's observation "Animals are painted by Nature, darkest on those parts which tend to be most lighted by the sky's light, and vice versa" is called Thayer's Law.

Countershading is widely used by both terrestrial and marine animals. Examples include deer
Deer
Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...

 and shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....

s.

Countershading is relatively little used for military camouflage, despite Second World War experiments that demonstrated its effectiveness. English
English people
The English are a nation and ethnic group native to England, who speak English. The English identity is of early mediaeval origin, when they were known in Old English as the Anglecynn. England is now a country of the United Kingdom, and the majority of English people in England are British Citizens...

 Zoologist Hugh B. Cott
Hugh B. Cott
Hugh B. Cott , born Hugh Bamford Cott, was a British zoologist, an authority on both natural and military camouflage, and a scientific illustrator and photographer. Many of his field studies took place in Africa, where he was especially interested in the Nile crocodile.-Background:Cott was born in...

 encouraged the use of techniques including Countershading to provide effective concealment, observing that soldiers viewed camouflage netting as "some kind of invisibility cloak: just throw it over the truck and now you don't see it", as Peter Forbes comments. At the same time in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

, Zoologist William John Dakin advised soldiers to copy animals' methods, using their instincts for wartime camouflage.


Crypsis by counterillumination


Counterillumination means producing light to match the background, notably in some species of Squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...

, such as the Sparkling Enope Squid (Watasenia scintillans) and the Midwater Squid (Abralia veranyi). Abralia has light-producing organs (photophores) scattered all over its underside; these create a sparkling glow that prevents the animal from appearing as a dark shape when seen from below.

Counterillumination is the likely function of the bioluminescence
Bioluminescence
Bioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...

 of many marine organisms, though light is also produced to attract prey and for signalling.

Military dazzle 'camouflage'


Dazzle patterning
Dazzle camouflage
Dazzle camouflage, also known as Razzle Dazzle or Dazzle painting, was a camouflage paint scheme used on ships, extensively during World War I and to a lesser extent in World War II...

 superficially resembles disruptive patterning, but has a different purpose. It was used on ships during the First World War, not to make vessels hard to see, but to make their speed, size, range and direction difficult to ascertain by eye. Dazzle patterning is therefore arguably (by definition) not camouflage, though it has been called camouflage since the First World War. Non-aligning dazzle patterns may have helped to confuse gunners using optical rangefinders, where two halves of the image had to be aligned by eye to estimate the range to the target ship. However the evidence for its success is mixed.

Motion dazzle


Motion dazzle is caused by rapidly-moving bold patterns of contrasting stripes, as when Zebra
Zebra
Zebras are several species of African equids united by their distinctive black and white stripes. Their stripes come in different patterns unique to each individual. They are generally social animals that live in small harems to large herds...

s run from a lion. Motion dazzle may degrade predators' ability to estimate the prey's speed and direction accurately, giving the prey an improved chance of escape. Since dazzle patterns (such as the Zebra's stripes) make animals harder to catch when moving, but easier to detect when stationary, there is an evolutionary trade-off between dazzle and crypsis.


See also



  • Active camouflage
    Active camouflage
    Active camouflage or adaptive camouflage, is a group of camouflage technologies which allow an object to blend into its surroundings by use of panels or coatings capable of altering their appearance, color, luminance and reflective properties...

  • Animal coloration (including Mechanisms of colour production in animals)
  • Antipredator adaptation
  • Aposematism
    Aposematism
    Aposematism , perhaps most commonly known in the context of warning colouration, describes a family of antipredator adaptations where a warning signal is associated with the unprofitability of a prey item to potential predators...

  • Mimicry
  • Military camouflage
    Military camouflage
    Military camouflage is one of many means of deceiving an enemy. In practice, it is the application of colour and materials to battledress and military equipment to conceal them from visual observation. The French slang word camouflage came into common English usage during World War I when the...

  • Motion camouflage
    Motion camouflage
    Motion camouflage is a dynamic type of camouflage by which an object can approach a target while appearing to remain stationary from the perspective of the target. The attacking object simply remains on the line between the target and some landmark point, so it seems to stay near the landmark point...

  • Underwater camouflage and mimicry
    Underwater camouflage and mimicry
    Underwater camouflage and mimicry is a technique of crypsis—avoidance of observation—that allows an otherwise visible aquatic organism to remain indiscernible from the surrounding environment, or pretend to be something else by mimicking another organism or object...


Pioneering research

  • Hugh Cott (1940) Adaptive Coloration in Animals. Methuen, London.
  • E. B. Poulton (1890) The colours of Animals. London.
  • Abbott Handerson Thayer
    Abbott Handerson Thayer
    Abbott Handerson Thayer was an American artist, naturalist and teacher. As a painter of portraits, figures, animals and landscapes, he enjoyed a certain prominence during his lifetime, as indicated by the fact that his paintings are part of the most important U.S. art collections...

     and G. H. Thayer (1909) Concealing Colouration in the Animal Kingdom. New York.

Recent research

  • Martin Stevens and Sami Merilaita (editors). Animal Camouflage: Mechanisms and Function. Cambridge University Press, 2011.

  • Martin Stevens, Innes C Cuthill, Amy M.M Windsor, and Hannah J Walker, Disruptive contrast in animal camouflage. Proceedings of the Royal Society B: Biological Sciences. 2006 October 7; 273(1600): 2433–2438. Published online 2006 July 5. doi: 10.1098/rspb.2006.3614 Whole Text

General reading

  • Peter Forbes. Dazzled and Deceived: Mimicry and Camouflage. Yale, 2009.
  • Wickler, W. Mimicry in plants and animals. McGraw-Hill, 1968.

Children's books

  • B. Kalman and J. Crossingham. What are Camouflage and Mimicry?. Crabtree Publishing. (ages 4-8)
  • Rene Mettler. Animal Camouflage. Moonlight Publishing. First Discovery series, 2001. (ages 4-8)

General reading

  • Roy Behrens. False Colors: Art, Design and Modern Camouflage. Bobolink Books, 2002.
  • Henrietta Gooden. Camouflage and Art: Design for Deception in World War 2. Unicorn Press, 2009.
  • Jon Latimer
    Jon Latimer
    Jonathan David Latimer was an historian and writer based in Wales. His books include Operation Compass 1940 , Tobruk 1941 , Deception in War , Alamein , Burma: The Forgotten War and 1812: War with America which won a...

    , Deception in War, London: John Murray, 2001.
  • Newark, Tim. Camouflage. Thames and Hudson, with Imperial War Museum, 2007.

External links