![Maskowanie](https://upload.wikimedia.org/wikipedia/commons/7/71/Maskowanie.JPEG)
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the
leopard
The leopard (''Panthera pardus'') is one of the five extant species in the genus '' Panthera'', a member of the cat family, Felidae. It occurs in a wide range in sub-Saharan Africa, in some parts of Western and Central Asia, Southern Russia, a ...
's spotted coat, the
battledress
A combat uniform, also called field uniform, battledress or military fatigues, is a casual type of uniform used by military, police, fire and other public uniformed services for everyday fieldwork and combat duty purposes, as opposed to dress ...
of a modern
soldier
A soldier is a person who is a member of an army. A soldier can be a conscripted or volunteer enlisted person, a non-commissioned officer, or an officer.
Etymology
The word ''soldier'' derives from the Middle English word , from Old French ...
, and the
leaf-mimic katydid
There are many insects in the family Tettigoniidae (bush crickets or katydids) which are mimics of leaves.
This type of camouflage occurs in several subfamilies including the:
* Pterochrozinae
* Phaneropterinae
* Pseudophyllinae
Other unrelated ...
's wings. A third approach, motion dazzle, confuses the observer with a conspicuous pattern, making the object visible but momentarily harder to locate, as well as making general aiming easier. The majority of camouflage methods aim for crypsis, often through a general resemblance to the background, high contrast
disruptive coloration
Disruptive coloration (also known as disruptive camouflage or disruptive patterning) is a form of camouflage that works by breaking up the outlines of an animal, soldier or military vehicle with a strongly contrasting pattern. It is often comb ...
, eliminating shadow, and
countershading
Countershading, or Thayer's law, is a method of camouflage in which an animal's coloration is darker on the top or upper side and lighter on the underside of the body. This pattern is found in many species of mammals, reptiles, birds, fish, and ...
. In the open ocean, where there is no background, the principal methods of camouflage are transparency, silvering, and countershading, while the
ability to produce light is among other things used for
counter-illumination
Counter-illumination is a method of active camouflage seen in marine animals such as firefly squid and midshipman fish, and in military prototypes, producing light to match their backgrounds in both brightness and wavelength.
Marine animals of ...
on the undersides of
cephalopod
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
s such as
squid
True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...
. Some animals, such as
chameleon
Chameleons or chamaeleons (family Chamaeleonidae) are a distinctive and highly specialized clade of Old World lizards with 202 species described as of June 2015. The members of this family are best known for their distinct range of colors, bein ...
s and
octopus
An octopus ( : octopuses or octopodes, see below for variants) is a soft-bodied, eight- limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttle ...
es, are capable of
actively changing their skin pattern and colours, whether for camouflage or for signalling. It is possible that some plants use camouflage to evade being eaten by
herbivore
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
s.
Military camouflage
Military camouflage is the use of camouflage by an armed force to protect personnel and equipment from observation by enemy forces. In practice, this means applying colour and materials to military equipment of all kinds, including vehicles, ...
was spurred by the increasing range and accuracy of firearms in the 19th century. In particular the replacement of the inaccurate
musket
A musket is a muzzle-loaded long gun that appeared as a smoothbore weapon in the early 16th century, at first as a heavier variant of the arquebus, capable of penetrating plate armour. By the mid-16th century, this type of musket gradually d ...
with the
rifle
A rifle is a long-barreled firearm designed for accurate shooting, with a barrel that has a helical pattern of grooves ( rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with ...
made personal concealment in battle a survival skill. In the 20th century, military camouflage developed rapidly, especially during the
First World War
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
. On land, artists such as
André Mare
Charles André Mare (1885–1932), or André-Charles Mare, was a French painter and textile designer, and co-founder of the Company of French Art (''la Compagnie des Arts Français'') in 1919. He was a designer of colorful textiles, and was one o ...
designed camouflage schemes and observation posts disguised as trees.
At sea
The sea, connected as the world ocean or simply the ocean, is the body of salty water that covers approximately 71% of the Earth's surface. The word sea is also used to denote second-order sections of the sea, such as the Mediterranean Sea, ...
, merchant ships and troop carriers were painted in
dazzle
Dazzle may refer to:
* Glare (vision), difficulty seeing in the presence of bright light
* Dazzle (fabric), a type of polyester fabric
* ''Dazzle'' (manga), a Japanese manga series by Minari Endoh
* "Dazzle" (song), a song by Siouxsie & the Ban ...
patterns that were highly visible, but designed to confuse enemy submarines as to the target's speed, range, and heading. During and after the
Second World War
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, a variety of camouflage schemes were used for
aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines ...
and for ground vehicles in different theatres of war. The use of radar since the mid-20th century has largely made camouflage for fixed-wing military aircraft obsolete.
Non-military use of camouflage includes making
cell telephone towers less obtrusive and helping hunters to approach wary game animals. Patterns derived from military camouflage are frequently used in fashion clothing, exploiting their strong designs and sometimes their symbolism. Camouflage themes recur in modern art, and both figuratively and literally in science fiction and works of literature.
History
![Octopus cyaneain Kona](https://upload.wikimedia.org/wikipedia/commons/e/ed/Octopus_cyaneain_Kona.jpg)
In ancient Greece,
Aristotle
Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of phil ...
(384–322 BC) commented on the colour-changing abilities, both for camouflage and for
signalling
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...
, of
cephalopod
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
s including the octopus, in his ''
Historia animalium
''History of Animals'' ( grc-gre, Τῶν περὶ τὰ ζῷα ἱστοριῶν, ''Ton peri ta zoia historion'', "Inquiries on Animals"; la, Historia Animalium, "History of Animals") is one of the major texts on biology by the ancient Gr ...
'':
[Aristotle (c. 350 BC). ''Historia Animalium''. IX, 622a: 2–10. Cited in Borrelli, Luciana; Gherardi, Francesca; Fiorito, Graziano (2006). ''A catalogue of body patterning in Cephalopoda''. Firenze University Press. ]
Abstract
Camouflage has been a topic of interest and research in
zoology
Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the Animal, animal kingdom, including the anatomy, structure, embryology, evolution, Biological clas ...
for well over a century. According to
Charles Darwin
Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...
's 1859 theory of
natural selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charle ...
, features such as camouflage
evolved
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation t ...
by providing individual animals with a reproductive advantage, enabling them to leave more offspring, on average, than other members of the same
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
. In his ''
Origin of Species
''On the Origin of Species'' (or, more completely, ''On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life''),The book's full original title was ''On the Origin of Species by Me ...
'', Darwin wrote:
![Variable Protective Resemblance in Lepidopterous Pupae](https://upload.wikimedia.org/wikipedia/commons/6/61/Variable_Protective_Resemblance_in_Lepidopterous_Pupae.jpg)
The English zoologist
Edward Bagnall Poulton
Sir Edward Bagnall Poulton, FRS HFRSE FLS (27 January 1856 – 20 November 1943) was a British evolutionary biologist, a lifelong advocate of natural selection through a period in which many scientists such as Reginald Punnett doubted its i ...
studied
animal coloration
Animal coloration is the general appearance of an animal resulting from the reflection or emission of light from its surfaces. Some animals are brightly coloured, while others are hard to see. In some species, such as the peafowl, the male h ...
, especially camouflage. In his 1890 book ''
The Colours of Animals
''The Colours of Animals'' is a zoology book written in 1890 by Sir Edward Bagnall Poulton (1856–1943). It was the first substantial textbook to argue the case for Darwinian selection applying to all aspects of animal coloration. The book al ...
'', he classified different types such as "special protective resemblance" (where an animal looks like another object), or "general aggressive resemblance" (where a predator blends in with the background, enabling it to approach prey). His experiments showed that
swallow-tailed moth
The swallow-tailed moth (''Ourapteryx sambucaria'') is a moth of the family Geometridae. The species was first described by Carl Linnaeus in his 1758 10th edition of ''Systema Naturae''. It is a common species across Europe and the Near East. ...
pupae
A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their ...
were camouflaged to match the backgrounds on which they were reared as
larvae
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
. Poulton's "general protective resemblance" was at that time considered to be the main method of camouflage, as when
Frank Evers Beddard
Frank Evers Beddard FRS FRSE (19 June 1858 – 14 July 1925) was an English zoologist. He became a leading authority on annelids, including earthworms. He won the Linnean Medal in 1916 for his book on oligochaetes.
Life
Beddard was born in ...
wrote in 1892 that "tree-frequenting animals are often green in colour. Among vertebrates numerous species of
parrot
Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoid ...
s,
iguana
''Iguana'' (, ) is a genus of herbivorous lizards that are native to tropical areas of Mexico, Central America, South America, and the Caribbean. The genus was first described in 1768 by Austrian naturalist Josephus Nicolaus Laurenti in his bo ...
s,
tree-frogs, and the
green tree-snake are examples". Beddard did however briefly mention other methods, including the "alluring coloration" of the
flower mantis
Flower mantises are praying mantis species that use a special form of camouflage referred to as aggressive mimicry, which they not only use to attract prey, but avoid predators as well. These insects have specific colorations and behaviors that ...
and the possibility of a different mechanism in the
orange tip butterfly. He wrote that "the scattered green spots upon the under surface of the wings might have been intended for a rough sketch of the small flowerets of the plant
n_umbellifer.html" ;"title="umbellifer.html" ;"title="n umbellifer">n umbellifer">umbellifer.html" ;"title="n umbellifer">n umbellifer so close is their mutual resemblance." He also explained the coloration of sea fish such as the mackerel: "Among pelagic fish it is common to find the upper surface dark-coloured and the lower surface white, so that the animal is inconspicuous when seen either from above or below."
![PeacockInTheWoods](https://upload.wikimedia.org/wikipedia/commons/6/6f/PeacockInTheWoods.jpg)
The artist
Abbott Handerson Thayer
Abbott Handerson Thayer (August 12, 1849May 29, 1921) was an American artist, naturalist and teacher. As a painter of portraits, figures, animals and landscapes, he enjoyed a certain prominence during his lifetime, and his paintings are represen ...
formulated what is sometimes called Thayer's Law, the principle of
countershading
Countershading, or Thayer's law, is a method of camouflage in which an animal's coloration is darker on the top or upper side and lighter on the underside of the body. This pattern is found in many species of mammals, reptiles, birds, fish, and ...
. However, he overstated the case in the 1909 book ''
Concealing-Coloration in the Animal Kingdom
''Concealing-Coloration in the Animal Kingdom: An Exposition of the Laws of Disguise Through Color and Pattern; Being a Summary of Abbott H. Thayer’s Discoveries'' is a book published ostensibly by Gerald H. Thayer in 1909, and revised in 191 ...
'', arguing that "All patterns and colors whatsoever of all animals that ever preyed or are preyed on are under certain normal circumstances obliterative" (that is, cryptic camouflage), and that "Not one '
mimicry
In evolutionary biology, mimicry is an evolved resemblance between an organism and another object, often an organism of another species. Mimicry may evolve between different species, or between individuals of the same species. Often, mimicry f ...
' mark, not one '
warning color
Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste o ...
'... nor any '
sexually selected' color, exists anywhere in the world where there is not every reason to believe it the very best conceivable device for the concealment of its wearer", and using paintings such as ''Peacock in the Woods'' (1907) to reinforce his argument. Thayer was roundly mocked for these views by critics including
Teddy Roosevelt
Theodore Roosevelt Jr. ( ; October 27, 1858 – January 6, 1919), often referred to as Teddy or by his initials, T. R., was an American politician, statesman, soldier, conservationist, naturalist, historian, and writer who served as the 26t ...
.
The English zoologist
Hugh Cott
Hugh Bamford Cott (6 July 1900 – 18 April 1987) 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 especia ...
's 1940 book ''
Adaptive Coloration in Animals
''Adaptive Coloration in Animals'' is a 500-page textbook about camouflage, warning coloration and mimicry by the Cambridge zoologist Hugh Cott, first published during the Second World War in 1940; the book sold widely and made him famous.
The ...
'' corrected Thayer's errors, sometimes sharply: "Thus we find Thayer straining the theory to a fantastic extreme in an endeavour to make it cover almost every type of coloration in the animal kingdom." Cott built on Thayer's discoveries, developing a comprehensive view of camouflage based on "maximum disruptive contrast", countershading and hundreds of examples. The book explained how
disruptive camouflage
Disruptive coloration (also known as disruptive camouflage or disruptive patterning) is a form of camouflage that works by breaking up the outlines of an animal, soldier or military vehicle with a strongly contrasting pattern. It is often comb ...
worked, using streaks of boldly contrasting colour, paradoxically making objects less visible by breaking up their outlines. While Cott was more systematic and balanced in his view than Thayer, and did include some experimental evidence on the effectiveness of camouflage, his 500-page textbook was, like Thayer's, mainly a
natural history narrative which illustrated theories with examples.
Experimental evidence that camouflage helps prey avoid being detected by
predator
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
s was first provided in 2016, when ground-nesting birds (
plovers
Plovers ( , ) are a widely distributed group of wading birds belonging to the subfamily Charadriinae.
Description
There are about 66 species in the subfamily, most of them called "plover" or "dotterel". The closely related lapwing subfa ...
and
coursers
The coursers are a group of birds which together with the pratincoles make up the family Glareolidae. They have long legs, short wings and long pointed bills which curve downwards. Their most unusual feature for birds classed as waders is that ...
) were shown to survive according to how well their egg contrast matched the local environment.
Evolution
As there is a lack of evidence for camouflage in the fossil record, studying the evolution of camouflage strategies is very difficult. Furthermore, camouflage traits must be both adaptable (provide a fitness gain in a given environment) and heritable (in other words, the trait must undergo
positive selection
In population genetics, directional selection, is a mode of negative natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype. Under dir ...
). Thus, studying the evolution of camouflage strategies requires an understanding of the genetic components and various ecological pressures that drive crypsis.
Fossil history
Camouflage is a soft-tissue feature that is rarely preserved in the
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
record, but rare fossilised skin samples from the
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
period show that some marine reptiles were countershaded. The skins, pigmented with dark-coloured
eumelanin
Melanin (; from el, μέλας, melas, black, dark) is a broad term for a group of natural pigments found in most organisms. Eumelanin is produced through a multistage chemical process known as melanogenesis, where the oxidation of the amin ...
, reveal that both
leatherback turtle
The leatherback sea turtle (''Dermochelys coriacea''), sometimes called the lute turtle or leathery turtle or simply the luth, is the largest of all living turtles and the heaviest non-crocodilian reptile, reaching lengths of up to and weights ...
s and
mosasaur
Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Greek ' meaning 'lizard') comprise a group of extinct, large marine reptiles from the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on th ...
s had dark backs and light bellies. There is fossil evidence of camouflaged insects going back over 100 million years, for example lacewings larvae that stick debris all over their bodies much as their modern descendants do, hiding them from their prey. Dinosaurs appear to have been camouflaged, as a 120 million year old fossil of a ''
Psittacosaurus
''Psittacosaurus'' ( ; "parrot lizard") is a genus of extinct ceratopsian dinosaur from the Early Cretaceous of what is now Asia, existing between 126 and 101 million years ago. It is notable for being the most species-rich non-avian dinosaur gen ...
'' has been preserved with
countershading
Countershading, or Thayer's law, is a method of camouflage in which an animal's coloration is darker on the top or upper side and lighter on the underside of the body. This pattern is found in many species of mammals, reptiles, birds, fish, and ...
.
Genetics
Camouflage does not have a single genetic origin. However, studying the genetic components of camouflage in specific organisms illuminates the various ways that crypsis can evolve among lineages.
Many
cephalopod
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
s have the ability to actively camouflage themselves, controlling crypsis through neural activity. For example, the genome of the common cuttlefish includes 16 copies of the
reflectin
Reflectins are a family of intrinsically disordered proteins evolved by a certain number of cephalopods including ''Euprymna scolopes'' and ''Doryteuthis opalescens'' to produce Iridescence, iridescent camouflage and signaling. The recently identi ...
gene, which grants the organism remarkable control over coloration and iridescence. The reflectin gene is thought to have originated through transposition from symbiotic ''
Aliivibrio fischeri
''Aliivibrio fischeri'' (also called ''Vibrio fischeri'') is a Gram-negative, rod-shaped bacterium found globally in marine environments. This species has bioluminescent properties, and is found predominantly in symbiosis with various marine an ...
'' bacteria, which provide bioluminescence to its hosts. While not all cephalopods use
active camouflage
Active camouflage or adaptive camouflage is camouflage that adapts, often rapidly, to the surroundings of an object such as an animal or military vehicle. In theory, active camouflage could provide perfect concealment from visual detection.
Activ ...
, ancient cephalopods may have inherited the gene horizontally from symbiotic ''A. fischeri'', with divergence occurred through subsequent gene duplication (such as in the case of ''Sepia officinalis'') or gene loss (as with cephalopods with no active camouflage capabilities).
/sup> This is unique as an instance of camouflage arising as an instance of horizontal gene transfer
Horizontal gene transfer (HGT) or lateral gene transfer (LGT) is the movement of genetic material between Unicellular organism, unicellular and/or multicellular organisms other than by the ("vertical") transmission of DNA from parent to offsprin ...
from an endosymbiont
An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship.
(The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within" ...
. However, other methods of horizontal gene transfer are common in the evolution of camouflage strategies in other lineages. Peppered moths
The peppered moth (''Biston betularia'') is a temperate species of night-flying moth. It is mostly found in the northern hemisphere in places like Asia, Europe and North America. Peppered moth evolution is an example of population genetics an ...
and walking stick insects both have camouflage-related genes that stem from transposition events.
The Agouti
The agouti (, ) or common agouti is any of several rodent species of the genus ''Dasyprocta''. They are native to Middle America, northern and central South America, and the southern Lesser Antilles. Some species have also been introduced else ...
genes are orthologous genes involved in camouflage across many lineages. They produce yellow and red coloration (phaeomelanin
Melanin (; from el, μέλας, melas, black, dark) is a broad term for a group of natural pigments found in most organisms. Eumelanin is produced through a multistage chemical process known as melanogenesis, where the oxidation of the amino ...
), and work in competition with other genes that produce black (melanin) and brown (eumelanin) colours. In eastern deer mice, over a period of about 8000 years the single agouti gene developed 9 mutations that each made expression of yellow fur stronger under natural selection, and largely eliminated melanin-coding black fur coloration. On the other hand, all black domesticated cats have deletions of the agouti gene that prevent its expression, meaning no yellow or red color is produced. The evolution, history and widespread scope of the agouti gene shows that different organisms often rely on orthologous or even identical genes to develop a variety of camouflage strategies.
Ecology
While camouflage can increase an organism's fitness, it has genetic and energetic costs. There is a trade-off between detectability and mobility. Species camouflaged to fit a specific microhabitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
are less likely to be detected when in that microhabitat, but must spend energy to reach, and sometimes to remain in, such areas. Outside the microhabitat, the organism has a higher chance of detection. Generalized camouflage allows species to avoid predation over a wide range of habitat backgrounds, but is less effective. The development of generalized or specialized camouflage strategies is highly dependent on the biotic and abiotic composition of the surrounding environment.
There are many examples of the tradeoffs between specific and general cryptic patterning. ''Phestilla
''Phestilla'' is a genus of sea slugs, aeolid nudibranchs, marine gastropod molluscs in the family Trinchesiidae.
Its members are unusual in feeding on hard corals, unlike other members of the family Trinchesiidae which feed on hydroids. Adult ...
melanocrachia'', a species of nudibranch that feeds on stony coral
Scleractinia, also called stony corals or hard corals, are marine animals in the phylum Cnidaria that build themselves a hard skeleton. The individual animals are known as polyps and have a cylindrical body crowned by an oral disc in which a ...
, utilizes specific cryptic patterning in reef ecosystems. The nudibranch syphons pigments from the consumed coral into the epidermis, adopting the same shade as the consumed coral. This allows the nudibranch to change colour (mostly between black and orange) depending on the coral system that it inhabits. However, ''P. melanocrachia'' can only feed and lay eggs on the branches of host-coral, '' Platygyra carnosa'', which limits the geographical range and efficacy in nudibranch nutritional crypsis. Furthermore, the nudibranch colour change is not immediate, and switching between coral hosts when in search for new food or shelter can be costly.
The costs associated with distractive or disruptive crypsis are more complex than the costs associated with background matching. Disruptive patterns distort the body outline, making it harder to precisely identify and locate. However, disruptive patterns result in higher predation. Disruptive patterns that specifically involve visible symmetry (such as in some butterflies) reduce survivability and increase predation. Some researchers argue that because wing-shape and color pattern are genetically linked, it is genetically costly to develop asymmetric wing colorations that would enhance the efficacy of disruptive cryptic patterning. Symmetry does not carry a high survival cost for butterflies and moths that their predators views from above on a homogeneous background, such as the bark of a tree. On the other hand, natural selection drives species with variable backgrounds and habitats to move symmetrical patterns away from the centre of the wing and body, disrupting their predators' symmetry recognition.
Principles
Camouflage can be achieved by different methods, described below. Most of the methods help to hide against a background; but mimesis and motion dazzle protect without hiding. Methods may be applied on their own or in combination. Many mechanisms are visual, but some research has explored the use of techniques against olfactory
The sense of smell, or olfaction, is the special sense through which smells (or odors) are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste.
In humans, it ...
(scent) and acoustic (sound) detection. Methods may also apply to military equipment.
Resemblance to surroundings
Some animals' colours and patterns resemble a particular natural background. This is an important component of camouflage in all environments. For instance, tree-dwelling parakeet
A parakeet is any one of many small to medium-sized species of parrot, in multiple Genus, genera, that generally has long tail feathers.
Etymology and naming
The name ''parakeet'' is derived from the French wor''perroquet'' which is reflec ...
s are mainly green; woodcock
The woodcocks are a group of seven or eight very similar living species of wading birds in the genus ''Scolopax''. The genus name is Latin for a snipe or woodcock, and until around 1800 was used to refer to a variety of waders. The English name ...
s of the forest floor are brown and speckled; reedbed bittern
Bitterns are birds belonging to the subfamily Botaurinae of the heron family Ardeidae. Bitterns tend to be shorter-necked and more secretive than other members of the family. They were called ''hæferblæte'' in Old English; the word "bittern" ...
s are streaked brown and buff; in each case the animal's coloration matches the hues of its habitat. Similarly, desert animals
A xerocole (), is a general term referring to any animal that is adapted to live in a desert. The main challenges xerocoles must overcome are lack of water and excessive heat. To conserve water they avoid evaporation and concentrate excretions (i. ...
are almost all desert coloured in tones of sand, buff, ochre, and brownish grey, whether they are mammals like the gerbil
The Mongolian gerbil or Mongolian jird (''Meriones unguiculatus'') is a small rodent belonging to the subfamily Gerbillinae. Their body size is typically , with a tail, and body weight , with adult males larger than females. The animal is use ...
or fennec fox
The fennec fox (''Vulpes zerda'') is a small crepuscular fox native to the deserts of North Africa, ranging from Western Sahara to the Sinai Peninsula. Its most distinctive feature is its unusually large ears, which serve to dissipate heat and l ...
, birds such as the desert lark
The desert lark (''Ammomanes deserti'') breeds in deserts and semi-deserts from Morocco to western India. It has a very wide distribution and faces no obvious threats, and surveys have shown that it is slowly increasing in numbers as it expands ...
or sandgrouse
Sandgrouse is the common name for Pteroclidae , a family (biology), family of sixteen species of bird, members of the order Pterocliformes . They are traditionally placed in two Genus, genera. The two central Asian species are classified as ''Sy ...
, or reptiles like the skink
Skinks are lizards belonging to the family Scincidae, a family in the infraorder Scincomorpha. With more than 1,500 described species across 100 different taxonomic genera, the family Scincidae is one of the most diverse families of lizards. Ski ...
or horned viper Horned viper may refer to:
* ''Cerastes (genus)'', North African desert vipers, a group of small, venomous species found in the deserts and semi-deserts of northern North Africa eastward through Arabia and Iran
* ''Bitis caudalis'', the horned puff ...
. Military uniforms, too, generally resemble their backgrounds; for example khaki
The color khaki (, ) is a light shade of tan with a slight yellowish tinge.
Khaki has been used by many armies around the world for uniforms and equipment, particularly in arid or desert regions, where it provides camouflage relative to sandy ...
uniforms are a muddy or dusty colour, originally chosen for service in South Asia. Many moths show industrial melanism
Industrial melanism is an evolutionary effect prominent in several arthropods, where dark pigmentation (melanism) has evolved in an environment affected by industrial pollution, including sulphur dioxide gas and dark soot deposits. Sulphur diox ...
, including the peppered moth
The peppered moth (''Biston betularia'') is a temperate species of night-flying moth. It is mostly found in the northern hemisphere in places like Asia, Europe and North America. Peppered moth evolution is an example of population genetics an ...
which has coloration that blends in with tree bark. The coloration of these insects evolved between 1860 and 1940 to match the changing colour of the tree trunks on which they rest, from pale and mottled to almost black in polluted areas. This is taken by zoologists as evidence that camouflage is influenced by natural selection, as well as demonstrating that it changes where necessary to resemble the local background.
File:Tanzania 0607 cropped Nevit.jpg, Black-faced sandgrouse is coloured like its desert background.
File:Caprimulgus aegyptius.jpg, Egyptian nightjar
The Egyptian nightjar (''Caprimulgus aegyptius'') is a medium-small nightjar which occurs in south west Asia and north Africa and winters in tropical Africa. This is a fairly common species with a wide distribution which faces no obvious threats ...
nests in open sand with only its camouflaged plumage to protect it.
File:Podargus papuensis - Daintree River.jpg, Papuan frogmouth
The Papuan frogmouth (''Podargus papuensis'') is a species of bird in the family Podargidae.
Taxonomy
The species was originally described by zoologist Jean René Constant Quoy and naturalist Joseph Paul Gaimard in 1830.
The three subspeci ...
resembles a broken branch.
File:Katydid camouflaged in basil plant.jpg, Bright green katydid
Insects in the family Tettigoniidae are commonly called katydids (especially in North America), or bush crickets. They have previously been known as "long-horned grasshoppers". More than 8,000 species are known. Part of the suborder Ensifera, t ...
has the colour of fresh vegetation.
Disruptive coloration
Disruptive patterns use strongly contrasting, non-repeating markings such as spots or stripes to break up the outlines of an animal or military vehicle, or to conceal telltale features, especially by masking the eyes, as in the common frog
The common frog or grass frog (''Rana temporaria''), also known as the European common frog, European common brown frog, European grass frog, European Holarctic true frog, European pond frog or European brown frog, is a semi-aquatic amphibian o ...
. Disruptive patterns may use more than one method to defeat visual systems such as edge detection
Edge detection includes a variety of mathematical methods that aim at identifying edges, curves in a digital image at which the image brightness changes sharply or, more formally, has discontinuities. The same problem of finding discontinuitie ...
. Predators like the leopard
The leopard (''Panthera pardus'') is one of the five extant species in the genus '' Panthera'', a member of the cat family, Felidae. It occurs in a wide range in sub-Saharan Africa, in some parts of Western and Central Asia, Southern Russia, a ...
use disruptive camouflage to help them approach prey, while potential prey use it to avoid detection by predators. Disruptive patterning is 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 factors like shape, shine, and shadow.
The presence of bold skin markings does not in itself prove that an animal relies on camouflage, as that depends on its behaviour.[ Roosevelt attacks Thayer on page 191, arguing that neither zebra nor giraffe are "'adequately obliterated' by countershading or coloration pattern or anything else."] For example, although giraffe
The giraffe is a large African hoofed mammal belonging to the genus ''Giraffa''. It is the tallest living terrestrial animal and the largest ruminant on Earth. Traditionally, giraffes were thought to be one species, ''Giraffa camelopardalis ...
s have a high contrast pattern that could be disruptive coloration, the adults are very conspicuous when in the open. Some authors have argued that adult giraffes are cryptic, since when standing among trees and bushes they are hard to see at even a few metres' distance. However, adult giraffes move about to gain the best view of an approaching predator, relying on their size and ability to defend themselves, even from lions, rather than on camouflage. A different explanation is implied by young giraffes being far more vulnerable to predation than adults. More than half of all giraffe calves die within a year, and giraffe mothers hide their newly born calves, which spend much of the time lying down in cover while their mothers are away feeding. The mothers return once a day to feed their calves with milk. Since the presence of a mother nearby does not affect survival, it is argued that these juvenile giraffes must be very well camouflaged; this is supported by coat markings being strongly inherited.
The possibility of camouflage in plants has been little studied until the late 20th century. Leaf variegation
Variegation is the appearance of differently coloured zones in the leaves and sometimes the stems and fruit of plants. Species with variegated individuals are sometimes found in the understory of tropical rainforests, and this habitat is the s ...
with white spots may serve as camouflage in forest understory
In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but abov ...
plants, where there is a dappled background; leaf mottling is correlated with closed habitats. Disruptive camouflage would have a clear evolutionary advantage in plants: they would tend to escape from being eaten by herbivore
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
s. Another possibility is that some plants have leaves differently coloured on upper and lower surfaces or on parts such as veins and stalks to make green-camouflaged insects conspicuous, and thus benefit the plants by favouring the removal of herbivores by carnivores. These hypotheses are testable.
File:Great male Leopard in South Afrika-JD.JPG, Leopard: a disruptively camouflaged predator
File:T-90 main battle tank (2).jpg, Russian T-90 battle tank painted in bold disruptive pattern of sand and green
File:Gaboon viper (4530693343).jpg, Gaboon viper
The Gaboon viper (''Bitis gabonica''), also called the Gaboon adder, is a viper species found in the rainforests and savannas of sub-Saharan Africa.McDiarmid RW, Campbell JA, Touré T. 1999. ''Snake Species of the World: A Taxonomic and Geograp ...
's bold markings are powerfully disruptive.
File:Ptarmigan and five chicks.JPG, A ptarmigan
''Lagopus'' is a small genus of birds in the grouse subfamily commonly known as ptarmigans (). The genus contains three living species with numerous described subspecies, all living in tundra or cold upland areas.
Taxonomy and etymology
The ge ...
and five chicks exhibit exceptional disruptive camouflage
File:Jumping spider with prey.jpg, Jumping spider
Jumping spiders are a group of spiders that constitute the family (biology), family Salticidae. As of 2019, this family contained over 600 described genera and over 6,000 described species, making it the largest family of spiders at 13% of all sp ...
: a disruptively camouflaged invertebrate predator
File:Saw Greenbriar - Smilax bona-nox, Colt Creek State Park, Lakeland, Florida.jpg, Many understory
In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but abov ...
plants such as the saw greenbriar, ''Smilax bona-nox
''Smilax bona-nox'', the saw greenbrier, is a species of plant in the family Smilacaceae. It is native to the Southern United States
The Southern United States (sometimes Dixie, also referred to as the Southern States, the American South, t ...
'' have pale markings, possibly disruptive camouflage.
Eliminating shadow
Some animals, such as the horned lizard
Horned lizards (''Phrynosoma''), also known as horny toads or horntoads, are a genus of North American lizards and the type genus of the family Phrynosomatidae. The common names refer directly to their horns or to their flattened, rounded bodies, ...
s of North America, have evolved elaborate measures to eliminate shadow
A shadow is a dark area where light from a light source is blocked by an opaque object. It occupies all of the three-dimensional volume behind an object with light in front of it. The cross section of a shadow is a two-dimensional silhouette, o ...
. Their bodies are flattened, with the sides thinning to an edge; the animals habitually press their bodies to the ground; and their sides are fringed with white scales which effectively hide and disrupt any remaining areas of shadow there may be under the edge of the body. The theory that the body shape of the horned lizards which live in open desert is adapted to minimise shadow is supported by the one species which lacks fringe scales, the roundtail horned lizard, which lives in rocky areas and resembles a rock. When this species is threatened, it makes itself look as much like a rock as possible by curving its back, emphasizing its three-dimensional shape. Some species of butterflies, such as the speckled wood, ''Pararge aegeria
The speckled wood (''Pararge aegeria'') is a butterfly found in and on the borders of woodland areas throughout much of the Palearctic realm. The species is subdivided into multiple subspecies, including ''Pararge aegeria aegeria'', ''Pararge aeg ...
'', minimise their shadows when perched by closing the wings over their backs, aligning their bodies with the sun, and tilting to one side towards the sun, so that the shadow becomes a thin inconspicuous line rather than a broad patch. Similarly, some ground-nesting birds, including the European nightjar
The European nightjar (''Caprimulgus europaeus''), common goatsucker, Eurasian nightjar or just nightjar, is a crepuscular and nocturnal bird in the nightjar family that breeds across most of Europe and the Palearctic to Mongolia and Northwest ...
, select a resting position facing the sun. Eliminating shadow was identified as a principle of military camouflage during the Second World War
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
.
File:Ibexes.jpg, Three countershaded and cryptically coloured ibex
An ibex (plural ibex, ibexes or ibices) is any of several species of wild goat (genus ''Capra''), distinguished by the male's large recurved horns, which are transversely ridged in front. Ibex are found in Eurasia, North Africa and East Africa. ...
almost invisible in the Israeli desert
File:Armoured personnel carriers, Eriboll - geograph.org.uk - 1316295.jpg, "Shape, shine, shadow" make these 'camouflaged' military vehicles easily visible.
File:Phrynosoma mcallii.jpg, The flat-tail horned lizard
The flat-tail horned lizard (''Phrynosoma mcallii'' ) is a species of lizard in the family Phrynosomatidae. A species of reptile, it is endemic to the Sonoran desert of the southwestern United States and northwestern Mexico. Its multiple adaptati ...
's body is flattened and fringed to minimise its shadow.
File:Øvelse på Evjemoen Tropp 4.2 - camouflage nettings.jpg, Camouflage netting
In law, set-off or netting are legal techniques applied between persons or businesses with mutual rights and liabilities, replacing gross positions with net positions. It permits the rights to be used to discharge the liabilities where cross cla ...
is draped away from a military vehicle to reduce its shadow.
File:Perfect Camouflage (Caterpillar on teakwood branch).jpg, A caterpillar's fringe of bristles conceals its shadow.
Distraction
Many prey animals have conspicuous high-contrast markings which paradoxically attract the predator's gaze. These distractive markings
Distractive markings serve to camouflage animals or military vehicles by drawing the observer's attention away from the object as a whole, such as noticing its outline. This delays recognition. The markings necessarily have high contrast and are th ...
may serve as camouflage by distracting the predator's attention from recognising the prey as a whole, for example by keeping the predator from identifying the prey's outline. Experimentally, search times for blue tit
The Eurasian blue tit (''Cyanistes caeruleus'') is a small passerine bird in the tit family, Paridae. It is easily recognisable by its blue and yellow plumage and small size.
Eurasian blue tits, usually resident and non-migratory birds, are ...
s increased when artificial prey had distractive markings.
Self-decoration
Some animals actively seek to hide by decorating themselves with materials such as twigs, sand, or pieces of shell from their environment, to break up their outlines, to conceal the features of their bodies, and to match their backgrounds. For example, a caddisfly
The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the b ...
larva builds a decorated case and lives almost entirely inside it; a decorator crab
Decorator crabs are crabs of several different species, belonging to the superfamily Majoidea (not all of which are decorators), that use materials from their environment to hide from, or ward off, predators. They decorate themselves by sticking ...
covers its back with seaweed, sponges, and stones. The nymph
A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are ty ...
of the predatory masked bug uses its hind legs and a ' tarsal fan' to decorate its body with sand or dust. There are two layers of bristles (trichome
Trichomes (); ) are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a pla ...
s) over the body. On these, the nymph spreads an inner layer of fine particles and an outer layer of coarser particles. The camouflage may conceal the bug from both predators and prey.
Similar principles can be applied for military purposes, for instance when a sniper
A sniper is a military/paramilitary marksman who engages targets from positions of concealment or at distances exceeding the target's detection capabilities. Snipers generally have specialized training and are equipped with high-precision r ...
wears a ghillie suit
A ghillie suit is a type of camouflage clothing designed to resemble the background environment such as foliage, snow or sand. Typically, it is a net or cloth garment covered in loose strips of burlap ( hessian), cloth, or twine, sometimes made t ...
designed to be further camouflaged by decoration with materials such as tufts of grass from the sniper's immediate environment. Such suits were used as early as 1916, the British army having adopted "coats of motley hue and stripes of paint" for snipers. Cott takes the example of the larva of the blotched emerald
The blotched emerald (''Comibaena bajularia'') is a moth of the family Geometridae. The species was first described by Michael Denis and Ignaz Schiffermüller in 1775. It is found throughout Europe and the Near East. It has a scattered distribu ...
moth, which fixes a screen of fragments of leaves to its specially hooked bristles, to argue that military camouflage uses the same method, pointing out that the "device is ... essentially the same as one widely practised during the Great War for the concealment, not of caterpillars, but of caterpillar-tractors, unbattery positions, observation posts and so forth."
File:Hyastenus elatus.jpg, This decorator crab
Decorator crabs are crabs of several different species, belonging to the superfamily Majoidea (not all of which are decorators), that use materials from their environment to hide from, or ward off, predators. They decorate themselves by sticking ...
has covered its body with sponges.
File:IDF-CombatEngineeringSniper001.jpg, Sniper in a Ghillie suit
A ghillie suit is a type of camouflage clothing designed to resemble the background environment such as foliage, snow or sand. Typically, it is a net or cloth garment covered in loose strips of burlap ( hessian), cloth, or twine, sometimes made t ...
with plant materials
File:Reduvius personatus, Masked Hunter Bug nymph camouflaged with sand grains.JPG, ''Reduvius personatus
''Reduvius personatus'' or the masked hunter is an insect belonging to the assassin bug (Reduviidae) family. The name is because its nymphs camouflage themselves with dust. The masked hunter is a predator of small arthropods, including woodlice, ...
'', masked hunter bug nymph, camouflaged with sand grains
File:Battle of Lake Khasan-Camouflaged soviet tanks.jpg, Soviet tanks under netting dressed with vegetation, 1938
Cryptic behaviour
Movement catches the eye of prey animals on the lookout for predators, and of predators hunting for prey. Most methods of crypsis therefore also require suitable cryptic behaviour, such as lying down and keeping still to avoid being detected, or in the case of stalking predators such as the tiger
The tiger (''Panthera tigris'') is the largest living cat species and a member of the genus '' Panthera''. It is most recognisable for its dark vertical stripes on orange fur with a white underside. An apex predator, it primarily preys on u ...
, moving with extreme stealth, both slowly and quietly, watching its prey for any sign they are aware of its presence. As an example of the combination of behaviours and other methods of crypsis involved, young giraffes seek cover, lie down, and keep still, often for hours until their mothers return; their skin pattern blends with the pattern of the vegetation, while the chosen cover and lying position together hide the animals' shadows.[ The ]flat-tail horned lizard
The flat-tail horned lizard (''Phrynosoma mcallii'' ) is a species of lizard in the family Phrynosomatidae. A species of reptile, it is endemic to the Sonoran desert of the southwestern United States and northwestern Mexico. Its multiple adaptati ...
similarly relies on a combination of methods: it is adapted to lie flat in the open desert, relying on stillness, its cryptic coloration, and concealment of its shadow to avoid being noticed by predators. In the ocean, the leafy sea dragon
The leafy seadragon (''Phycodurus eques'') or Glauert's seadragon, is the only member of the genus ''Phycodurus'' and is a marine fish in the family Syngnathidae, which includes seadragons, pipefish, and seahorses.
It is found along the sou ...
sways mimetically, like the seaweeds amongst which it rests, as if rippled by wind or water currents. Swaying is seen also in some insects, like Macleay's spectre stick insect, ''Extatosoma tiaratum
''Extatosoma tiaratum'', commonly known as the spiny leaf insect, the giant prickly stick insect, Macleay's spectre, or the Australian walking stick, is a large species of Australian stick insect endemic to Australia. The species has the Phasmi ...
''. The behaviour may be motion crypsis, preventing detection, or motion masquerade, promoting misclassification (as something other than prey), or a combination of the two.
Motion camouflage
Most forms of camouflage are ineffective when the camouflaged animal or object moves, because the motion is easily seen by the observing predator, prey or enemy. However, insects such as hoverflies
Hover flies, also called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, whi ...
and dragonflies
A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threa ...
use motion camouflage
Motion camouflage is camouflage which provides a degree of concealment for a moving object, given that motion makes objects easy to detect however well their coloration matches their background or breaks up their outlines. The principal form ...
: the hoverflies to approach possible mates, and the dragonflies to approach rivals when defending territories. Motion camouflage is achieved by moving so as to stay on a straight line between the target and a fixed point in the landscape; the pursuer thus appears not to move, but only to loom larger in the target's field of vision. The same method can be used for military purposes, for example by missiles to minimise their risk of detection by an enemy. However, missile engineers, and animals such as bats, use the method mainly for its efficiency rather than camouflage.
File:Hoverfly August 2007-8.jpg, Male ''Syritta pipiens
''Syritta pipiens,'' sometimes called the thick-legged hoverfly, is one of the most common species in the insect family Syrphidae. This fly originates from Europe and is currently distributed across Eurasia and North America. They are fast and ...
'' hoverflies use motion camouflage to approach females
File:Australian Emperor mating and laying.jpg, Male Australian Emperor
The Australian emperor dragonfly,
also known as the yellow emperor dragonfly,
scientific name ''Anax papuensis'', is a species of dragonfly in the Aeshnidae family.
It is black with yellow dots along its tail.
Description
The Australian empero ...
dragonflies use motion camouflage to approach rivals.
Changeable skin coloration
Animals such as chameleon
Chameleons or chamaeleons (family Chamaeleonidae) are a distinctive and highly specialized clade of Old World lizards with 202 species described as of June 2015. The members of this family are best known for their distinct range of colors, bein ...
, frog, flatfish such as the peacock flounder
The peacock flounder (''Bothus mancus''), also known as the flowery flounder, is a species of fish in the family Bothidae (lefteye flounders). The species is found widely in relatively shallow waters in the Indo-Pacific, also ranging into warmer ...
, squid and octopus actively change their skin patterns and colours using special chromatophore
Chromatophores are cells that produce color, of which many types are Biological pigment, pigment-containing cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods. Mammals and ...
cells to resemble their current background, or, as in most chameleons, for signalling
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...
. However, Smith's dwarf chameleon
Smith's dwarf chameleon or the Elandsberg dwarf chameleon (''Bradypodion taeniabronchum'') is a species of lizard in the family Chamaeleonidae endemic to South Africa
South Africa, officially the Republic of South Africa (RSA), is the ...
does use active colour change for camouflage.
Each chromatophore contains pigment of only one colour. In fish and frogs, colour change is mediated by a type of chromatophore known as melanophore
Chromatophores are cells that produce color, of which many types are pigment-containing cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods. Mammals and birds, in contrast, ...
s that contain dark pigment. A melanophore is star-shaped; it contains many small pigmented organelle
In cell biology, an organelle is a specialized subunit, usually within a cell, that has a specific function. The name ''organelle'' comes from the idea that these structures are parts of cells, as organs are to the body, hence ''organelle,'' the ...
s which can be dispersed throughout the cell, or aggregated near its centre. When the pigmented organelles are dispersed, the cell makes a patch of the animal's skin appear dark; when they are aggregated, most of the cell, and the animal's skin, appears light. In frogs, the change is controlled relatively slowly, mainly by hormone
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required ...
s. In fish, the change is controlled by the brain, which sends signals directly to the chromatophores, as well as producing hormones.
The skins of cephalopods such as the octopus contain complex units, each consisting of a chromatophore with surrounding muscle and nerve cells. The cephalopod chromatophore has all its pigment grains in a small elastic sac, which can be stretched or allowed to relax under the control of the brain to vary its opacity. By controlling chromatophores of different colours, cephalopods can rapidly change their skin patterns and colours.
On a longer timescale, animals like the Arctic hare
The Arctic hare (''Lepus arcticus'') is a species of hare highly adapted to living in the Arctic tundra and other icy biomes. The Arctic hare survives with shortened ears and limbs, a small nose, fat that makes up close to 20% of its body, and ...
, Arctic fox
The Arctic fox (''Vulpes lagopus''), also known as the white fox, polar fox, or snow fox, is a small fox native to the Arctic regions of the Northern Hemisphere and common throughout the Arctic tundra biome. It is well adapted to living in co ...
, stoat
The stoat (''Mustela erminea''), also known as the Eurasian ermine, Beringian ermine and ermine, is a mustelid native to Eurasia and the northern portions of North America. Because of its wide circumpolar distribution, it is listed as Least Conc ...
, and rock ptarmigan
The rock ptarmigan (''Lagopus muta'') is a medium-sized game bird in the grouse family. It is known simply as the ptarmigan in the UK. It is the official bird for the Canadian territory of Nunavut, where it is known as the ''aqiggiq'' (ᐊᕿ ...
have snow camouflage
Snow camouflage is the use of a coloration or pattern for effective camouflage in winter, often combined with a different summer camouflage. Summer patterns are typically disruptively patterned combinations of shades of browns and greys, up to ...
, changing their coat colour (by moulting and growing new fur or feathers) from brown or grey in the summer to white in the winter; the Arctic fox is the only species in the dog family to do so. However, Arctic hares which live in the far north of Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
, where summer is very short, remain white year-round.
The principle of varying coloration either rapidly or with the changing seasons has military applications. ''Active camouflage
Active camouflage or adaptive camouflage is camouflage that adapts, often rapidly, to the surroundings of an object such as an animal or military vehicle. In theory, active camouflage could provide perfect concealment from visual detection.
Activ ...
'' could in theory make use of both dynamic colour change and counterillumination. Simple methods such as changing uniforms and repainting vehicles for winter have been in use since World War II. In 2011, BAE Systems
BAE Systems plc (BAE) is a British multinational arms, security, and aerospace company based in London, England. It is the largest defence contractor in Europe, and ranked the seventh-largest in the world based on applicable 2021 revenues. ...
announced their Adaptiv
Adaptiv is an active camouflage technology developed by BAE Systems AB to protect military vehicles from detection by far infrared night vision devices, providing infrared stealth. It consists of an array of hexagonal Peltier plates which can be ...
infrared camouflage technology. It uses about 1,000 hexagonal panels to cover the sides of a tank. The Peltier plate
The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa via a thermocouple. A thermoelectric device creates a voltage when there is a different temperature on each side. Conversely, when ...
panels are heated and cooled to match either the vehicle's surroundings (crypsis), or an object such as a car (mimesis), when viewed in infrared.
File:Rock Ptarmigan (Lagopus Muta).jpg, Rock ptarmigan, changing colour in springtime. The male is still mostly in winter plumage
File:Norwegian Winter War Volunteers.jpg, Norwegian volunteer soldiers in Winter War
The Winter War,, sv, Vinterkriget, rus, Зи́мняя война́, r=Zimnyaya voyna. The names Soviet–Finnish War 1939–1940 (russian: link=no, Сове́тско-финская война́ 1939–1940) and Soviet–Finland War 1 ...
, 1940, with white camouflage overalls over their uniforms
File:Arctic Hare.jpg, Arctic hares in the low arctic change from brown to white in winter
File:Bundesarchiv Bild 101III-Roth-173-01, Russland, Raum Charkow, Jagdpanzer.jpg, Snow-camouflaged German Marder III
''Marder'' III was the name for a series of World War II German tank destroyers. They mounted either the modified ex-Soviet 76.2 mm F-22 Model 1936 divisional field gun, or the German 7.5 cm PaK 40, in an open-topped fighting compartment on ...
jagdpanzer
''Jagdpanzer'' (JgPz) is the name given in German to a heavily-armoured, tracked tank destroyer, although it may also be used for other kinds of self-propelled guns. Literally translated from German, ''Jagdpanzer'' is "hunting tank".
It typi ...
and white-overalled crew and infantry in Russia, 1943
File:Yemen Chameleon (cropped).jpg, Veiled chameleon
The veiled chameleon (''Chamaeleo calyptratus'') is a species of chameleon (family Chamaeleonidae) native to the Arabian Peninsula in Yemen and Saudi Arabia. Other common names include cone-head chameleon and Yemen chameleon. They are born pas ...
, ''Chamaeleo calyptratus'', changes colour mainly in relation to mood and for signalling.
File:Adaptiv infrared camouflage demo hiding tank as car.jpg, Adaptiv
Adaptiv is an active camouflage technology developed by BAE Systems AB to protect military vehicles from detection by far infrared night vision devices, providing infrared stealth. It consists of an array of hexagonal Peltier plates which can be ...
infrared camouflage lets an armoured vehicle mimic a car.
Countershading
Countershading uses graded colour to counteract the effect of self-shadowing, creating an illusion of flatness. Self-shadowing makes an animal appear darker below than on top, grading from light to dark; countershading 'paints in' tones which are darkest on top, lightest below, making the countershaded animal nearly invisible against a suitable background. Thayer observed that "Animals are painted by Nature, darkest on those parts which tend to be most lighted by the sky's light, and ''vice versa''". Accordingly, the principle of countershading is sometimes called ''Thayer's Law''. Countershading is widely used by terrestrial animals
Terrestrial animals are animals that live predominantly or entirely on land (e.g. cats, dogs, ants, spiders), as compared with aquatic animals, which live predominantly or entirely in the water (e.g. fish, lobsters, octopuses), and amphibians, ...
, such as gazelle
A gazelle is one of many antelope species in the genus ''Gazella'' . This article also deals with the seven species included in two further genera, ''Eudorcas'' and ''Nanger'', which were formerly considered subgenera of ''Gazella''. A third f ...
s and grasshoppers; marine animals, such as sharks
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorp ...
and dolphins
A dolphin is an aquatic mammal within the infraorder Cetacea. Dolphin species belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontoporiidae (t ...
; and birds, such as snipe
A snipe is any of about 26 wading bird species in three genera in the family Scolopacidae. They are characterized by a very long, slender bill, eyes placed high on the head, and cryptic/camouflaging plumage. The ''Gallinago'' snipes have a near ...
and dunlin
The dunlin (''Calidris alpina'') is a small wader, formerly sometimes separated with the other "stints" in the genus ''Erolia''. The English name is a dialect form of "dunling", first recorded in 1531–1532. It derives from ''dun'', "dull brown ...
.
Countershading is less often used for military camouflage, despite Second World War experiments that showed its effectiveness. English zoologist
Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the Animal, animal kingdom, including the anatomy, structure, embryology, evolution, Biological clas ...
Hugh Cott
Hugh Bamford Cott (6 July 1900 – 18 April 1987) 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 especia ...
encouraged the use of methods including countershading, but despite his authority on the subject, failed to persuade the British authorities. Soldiers often wrongly viewed camouflage netting as a kind of invisibility cloak, and they had to be taught to look at camouflage practically, from an enemy observer's viewpoint. At the same time in Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
, zoologist William John Dakin
William John Dakin (23 July 1883 – 2 April 1950) was a zoology, zoologist who is remembered for the large number of his students who achieved prominence in the area of zoology and for the number of books and papers he wrote on many scientific f ...
advised soldiers to copy animals' methods, using their instincts for wartime camouflage.
The term countershading has a second meaning unrelated to "Thayer's Law". It is that the upper and undersides of animals such as sharks, and of some military aircraft, are different colours to match the different backgrounds when seen from above or from below. Here the camouflage consists of two surfaces, each with the simple function of providing concealment against a specific background, such as a bright water surface or the sky. The body of a shark or the fuselage of an aircraft is not gradated from light to dark to appear flat when seen from the side. The camouflage methods used are the matching of background colour and pattern, and disruption of outlines.[
File:Gazella-dorcas.jpg, Countershaded ]Dorcas gazelle
The dorcas gazelle (''Gazella dorcas''), also known as the ariel gazelle, is a small and common gazelle. The dorcas gazelle stands about at the shoulder, with a head and body length of and a weight of . The numerous subspecies survive on vegeta ...
, ''Gazella dorcas''
File:Tiburón.jpg, Countershaded grey reef shark
The grey reef shark (''Carcharhinus amblyrhynchos'', sometimes misspelled ''amblyrhynchus'' or ''amblyrhinchos'') is a species of requiem shark, in the family (biology), family Requiem shark, Carcharhinidae. One of the most common reef sharks in t ...
, ''Carcharhinus amblyrhynchos''
File:Thayers ships.jpg, Countershaded ship and submarine in Thayer's 1902 patent application
File:Abbott thayer countershading.jpg, Two model birds painted by Thayer: painted in background colours on the left, countershaded and nearly invisible on the right
File:Focke-Wulf Fw 190D-9 outside USAF.jpg, Countershaded Focke-Wulf Fw 190D-9
The Focke-Wulf Fw 190, nicknamed ''Würger'' ("Shrike") is a German single-seat, single-engine fighter aircraft designed by Kurt Tank at Focke-Wulf in the late 1930s and widely used during World War II. Along with its well-known counterpart, th ...
Counter-illumination
Counter-illumination means producing light to match a background that is brighter than an animal's body or military vehicle; it is a form of active camouflage. It is notably used by some species of squid
True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...
, such as the firefly squid
The firefly squid (''Watasenia scintillans''), also commonly known as the sparkling enope squid or hotaru-ika in Japan, is a species of squid in the family Enoploteuthidae. It is the sole species in the monotypic genus ''Watasenia''. These tiny s ...
and the midwater squid. The latter has light-producing organs (photophores
A photophore is a glandular organ that appears as luminous spots on various marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors, ...
) 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 camouflage is the likely function of the bioluminescence
Bioluminescence is the production and emission of light by living organisms. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some b ...
of many marine organisms, though light is also produced to attract or to detect prey and for signalling.
Counterillumination has rarely been used for military purposes. "Diffused lighting camouflage
Diffused lighting camouflage was a form of active camouflage using counter-illumination to enable a ship to match its background, the night sky, that was tested by the Royal Canadian Navy on corvettes during World War II. The principle was disc ...
" was trialled by Canada's National Research Council National Research Council may refer to:
* National Research Council (Canada), sponsoring research and development
* National Research Council (Italy), scientific and technological research, Rome
* National Research Council (United States), part of ...
during the Second World War. It involved projecting light on to the sides of ships to match the faint glow of the night sky, requiring awkward external platforms to support the lamps. The Canadian concept was refined in the American Yehudi lights
Yehudi lights are lamp (electrical component), lamps of automatically controlled brightness placed on the front and leading edges of an aircraft to raise the aircraft's luminance to the average brightness of the sky, a form of active camouflage ...
project, and trialled in aircraft including B-24 Liberators and naval Avengers
Avenger, Avengers, The Avenger, or The Avengers may refer to:
Arts and entertainment In the Marvel Comics universe
* Avengers (comics), a team of superheroes
**Avengers (Marvel Cinematic Universe), a central team of protagonist superheroes of ...
. The planes were fitted with forward-pointing lamps automatically adjusted to match the brightness of the night sky. This enabled them to approach much closer to a target – within – before being seen. Counterillumination was made obsolete by radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
, and neither diffused lighting camouflage nor Yehudi lights entered active service.
File:HMS Largs by night with incomplete Diffused Lighting Camouflage 1942.jpg, HMS ''Largs'' by night with incomplete diffused lighting camouflage
Diffused lighting camouflage was a form of active camouflage using counter-illumination to enable a ship to match its background, the night sky, that was tested by the Royal Canadian Navy on corvettes during World War II. The principle was disc ...
, 1942, set to maximum brightness
File:HMS Largs bulwark with Diffused Lighting Camouflage fittings.jpg, Bulwark of HMS ''Largs'' showing 4 (of about 60) diffused lighting fittings, 2 lifted, 2 deployed
File:Principle of Yehudi Lights with Avenger head-on view.jpg, Yehudi Lights
Yehudi lights are lamp (electrical component), lamps of automatically controlled brightness placed on the front and leading edges of an aircraft to raise the aircraft's luminance to the average brightness of the sky, a form of active camouflage ...
raise the average brightness of the plane from a dark shape to the same as the sky.
Transparency
Many marine
Marine is an adjective meaning of or pertaining to the sea or ocean.
Marine or marines may refer to:
Ocean
* Maritime (disambiguation)
* Marine art
* Marine biology
* Marine debris
* Marine habitats
* Marine life
* Marine pollution
Military
* ...
animals that float near the surface are highly transparent
Transparency, transparence or transparent most often refer to:
* Transparency (optics), the physical property of allowing the transmission of light through a material
They may also refer to:
Literal uses
* Transparency (photography), a still, ...
, giving them almost perfect camouflage. However, transparency is difficult for bodies made of materials that have different refractive indices
In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium.
The refractive index determines how much the path of light is bent, or ...
from seawater. Some marine animals such as jellyfish
Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella- ...
have gelatinous bodies, composed mainly of water; their thick mesogloea
Mesoglea refers to the extracellular matrix found in cnidarians like coral or jellyfish that functions as a hydrostatic skeleton. It is related to but distinct from mesohyl, which generally refers to extracellular material found in sponges.
Descr ...
is acellular and highly transparent. This conveniently makes them buoyant
Buoyancy (), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the pr ...
, but it also makes them large for their muscle mass, so they cannot swim fast, making this form of camouflage a costly trade-off with mobility. Gelatinous plankton
Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...
ic animals are between 50 and 90 percent transparent. A transparency of 50 percent is enough to make an animal invisible to a predator such as cod
Cod is the common name for the demersal fish genus '' Gadus'', belonging to the family Gadidae. Cod is also used as part of the common name for a number of other fish species, and one species that belongs to genus ''Gadus'' is commonly not call ...
at a depth of ; better transparency is required for invisibility in shallower water, where the light is brighter and predators can see better. For example, a cod can see prey that are 98 percent transparent in optimal lighting in shallow water. Therefore, sufficient transparency for camouflage is more easily achieved in deeper waters.
Some tissues such as muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
s can be made transparent, provided either they are very thin or organised as regular layers or fibrils that are small compared to the wavelength of visible light. A familiar example is the transparency of the lens of the vertebrate eye
Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...
, which is made of the protein crystallin
In anatomy, a crystallin is a water-soluble structural protein found in the lens and the cornea of the eye accounting for the transparency of the structure. It has also been identified in other places such as the heart, and in aggressive breast c ...
, and the vertebrate cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Along with the anterior chamber and lens, the cornea refracts light, accounting for approximately two-thirds of the eye's total optical power ...
which is made of the protein collagen
Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole ...
. Other structures cannot be made transparent, notably the retina
The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...
s or equivalent light-absorbing structures of eyes – they must absorb light to be able to function. The camera
A camera is an Optics, optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), ...
-type eye of vertebrates and cephalopods must be completely opaque. Finally, some structures are visible for a reason, such as to lure prey. For example, the nematocyst
A cnidocyte (also known as a cnidoblast or nematocyte) is an explosive cell containing one large secretory organelle called a cnidocyst (also known as a cnida () or nematocyst) that can deliver a sting to other organisms. The presence of this ce ...
s (stinging cells) of the transparent siphonophore
Siphonophorae (from Greek ''siphōn'' 'tube' + ''pherein'' 'to bear') is an order within Hydrozoa, which is a class of marine organisms within the phylum Cnidaria. According to the World Register of Marine Species, the order contains 175 specie ...
''Agalma okenii
An agalma ( grc, άγαλμα, , statue) is a cult image or votive offering.
Agalma may also refer to:
* ''Agalma'' (siphonophore), a marine animal genus in the family Agalmatidae
*''Agalma'', a synonym of the flowering plant genus ''Heptapleuru ...
'' resemble small copepod
Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...
s. Examples of transparent marine animals include a wide variety of larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
e, including radiata
Radiata or Radiates is a historical taxonomic rank that was used to classify animals with radially symmetric body plans. The term Radiata is no longer accepted, as it united several different groupings of animals that do not form a monophyletic ...
(coelenterates), siphonophores, salps
A salp (plural salps, also known colloquially as “sea grape”) or salpa (plural salpae or salpas) is a barrel-shaped, planktic tunicate. It moves by contracting, thereby pumping water through its gelatinous body, one of the most efficient ...
(floating tunicate
A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata (). It is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords (including vertebrates). The subphylum was at one time ca ...
s), gastropod molluscs, polychaete
Polychaeta () is a paraphyletic class (biology), class of generally marine invertebrate, marine annelid worms, common name, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that ...
worms, many shrimplike crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
s, and fish; whereas the adults of most of these are opaque and pigmented, resembling the seabed or shores where they live. Adult comb jellies
Ctenophora (; ctenophore ; ) comprise a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide. They are notable for the groups of cilia they use for swimming (commonly referred to as "combs"), an ...
and jellyfish obey the rule, often being mainly transparent. Cott suggests this follows the more general rule that animals resemble their background: in a transparent medium like seawater, that means being transparent. The small Amazon river
The Amazon River (, ; es, Río Amazonas, pt, Rio Amazonas) in South America is the largest river by discharge volume of water in the world, and the disputed longest river system in the world in comparison to the Nile.
The headwaters of t ...
fish ''Microphilypnus amazonicus
''Microphilypnus'' is a genus of small fishes in the family Eleotridae native to the Amazon and Orinoco basins in South America. At up to in standard length, they are among the smallest sleeper gobies, but however larger than the ''Leptophilypni ...
'' and the shrimps it associates with, ''Pseudopalaemon gouldingi
''Pseudopalaemon'' is a genus of shrimps belonging to the family Palaemonidae.
The species of this genus are found in Southern America.
Species:
*''Pseudopalaemon amazonensis''
*'' Pseudopalaemon bouvieri''
*''Pseudopalaemon chryseus''
*''Ps ...
'', are so transparent as to be "almost invisible"; further, these species appear to select whether to be transparent or more conventionally mottled (disruptively patterned) according to the local background in the environment.
Silvering
Where transparency cannot be achieved, it can be imitated effectively by silvering to make an animal's body highly reflective. At medium depths at sea, light comes from above, so a mirror oriented vertically makes animals such as fish invisible from the side. Most fish in the upper ocean such as sardine
"Sardine" and "pilchard" are common names for various species of small, oily forage fish in the herring family Clupeidae. The term "sardine" was first used in English during the early 15th century, a folk etymology says it comes from the Ital ...
and herring
Herring are forage fish, mostly belonging to the family of Clupeidae.
Herring often move in large schools around fishing banks and near the coast, found particularly in shallow, temperate waters of the North Pacific and North Atlantic Oceans, i ...
are camouflaged by silvering.
The marine hatchetfish
Marine hatchetfishes or deep-sea hatchetfishes are small deep-sea mesopelagic ray-finned fish of the stomiiform subfamily Sternoptychinae. They should not be confused with the freshwater hatchetfishes, which are not particularly closely relate ...
is extremely flattened laterally, leaving the body just millimetres thick, and the body is so silvery as to resemble aluminium foil
Aluminium foil (or aluminum foil in North American English; often informally called tin foil) is aluminium prepared in thin metal leaves with a thickness less than ; thinner gauges down to are also commonly used. Standard household foil is typ ...
. The mirrors consist of microscopic structures similar to those used to provide structural coloration
Structural coloration in animals, and a few plants, is the production of colour by microscopically structured surfaces fine enough to interfere with visible light instead of pigments, although some structural coloration occurs in combination wit ...
: stacks of between 5 and 10 crystals of guanine
Guanine () ( symbol G or Gua) is one of the four main nucleobases found in the nucleic acids DNA and RNA, the others being adenine, cytosine, and thymine (uracil in RNA). In DNA, guanine is paired with cytosine. The guanine nucleoside is called ...
spaced about of a wavelength apart to interfere constructively and achieve nearly 100 per cent reflection. In the deep waters that the hatchetfish lives in, only blue light with a wavelength of 500 nanometres percolates down and needs to be reflected, so mirrors 125 nanometres apart provide good camouflage.
In fish such as the herring which live in shallower water, the mirrors must reflect a mixture of wavelengths, and the fish accordingly has crystal stacks with a range of different spacings. A further complication for fish with bodies that are rounded in cross-section is that the mirrors would be ineffective if laid flat on the skin, as they would fail to reflect horizontally. The overall mirror effect is achieved with many small reflectors, all oriented vertically. Silvering is found in other marine animals as well as fish. The cephalopods
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, an ...
, including squid, octopus and cuttlefish, have multilayer mirrors made of protein rather than guanine.
Ultra-blackness
Some deep sea fishes have very black skin, reflecting under 0.5% of ambient light. This can prevent detection by predators or prey fish which use bioluminescence for illumination. ''Oneirodes
''Oneirodes'' is a genus of fish in the family Oneirodidae.
Species
There are currently 40 recognized species in this genus:
* '' Oneirodes acanthias'' ( C. H. Gilbert, 1915) (Spiny dreamer)
* '' Oneirodes alius'' Seigel & Pietsch, 1978
* '' O ...
'' had a particularly black skin which reflected only 0.044% of 480 nm wavelength light. The ultra-blackness is achieved with a thin but continuous layer of particles in the dermis
The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided i ...
, melanosome
A melanosome is an organelle found in animal cells and is the site for synthesis, storage and transport of melanin, the most common light-absorbing pigment found in the animal kingdom. Melanosomes are responsible for color and photoprotection i ...
s. These particles both absorb most of the light, and are sized and shaped so as to scatter rather than reflect most of the rest. Modelling suggests that this camouflage should reduce the distance at which such a fish can be seen by a factor of 6 compared to a fish with a nominal 2% reflectance. Species with this adaptation are widely dispersed in various orders of the phylogenetic tree
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...
of bony fishes (Actinopterygii
Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species.
The ray-finned fishes are so called because their fins are webs of skin supported by bony or h ...
), implying that natural selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charle ...
has driven the convergent evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...
of ultra-blackness camouflage independently many times.
Mimesis
In mimesis
Mimesis (; grc, μίμησις, ''mīmēsis'') is a term used in literary criticism and philosophy that carries a wide range of meanings, including ''imitatio'', imitation, nonsensuous similarity, receptivity, representation, mimicry, the act ...
(also called ''masquerade''), the camouflaged object looks like something else which is of no special interest to the observer. Mimesis is common in prey
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...
animals, for example when a peppered moth
The peppered moth (''Biston betularia'') is a temperate species of night-flying moth. It is mostly found in the northern hemisphere in places like Asia, Europe and North America. Peppered moth evolution is an example of population genetics an ...
caterpillar mimics a twig, or a grasshopper mimics a dry leaf. It is also found in nest structures; some eusocial wasps, such as '' Leipomeles dorsata'', build a nest envelope in patterns that mimic the leaves surrounding the nest.
Mimesis is also employed by some predators
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...
and parasite
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
s to lure their prey. For example, a flower mantis
Flower mantises are praying mantis species that use a special form of camouflage referred to as aggressive mimicry, which they not only use to attract prey, but avoid predators as well. These insects have specific colorations and behaviors that ...
mimics a particular kind of flower, such as an orchid
Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant.
Along with the Asteraceae, they are one of the two largest families of flowering ...
. This tactic has occasionally been used in warfare, for example with heavily armed Q-ship
Q-ships, also known as Q-boats, decoy vessels, special service ships, or mystery ships, were heavily armed merchant ships with concealed weaponry, designed to lure submarines into making surface attacks. This gave Q-ships the chance to open f ...
s disguised as merchant ships.
The common cuckoo
The common cuckoo (''Cuculus canorus'') is a member of the cuckoo order of birds, Cuculiformes, which includes the roadrunners, the anis and the coucals.
This species is a widespread summer migrant to Europe and Asia, and winters in Africa. I ...
, a brood parasite
Brood parasites are animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its own ...
, provides examples of mimesis both in the adult and in the egg. The female lays her eggs in nests of other, smaller species of bird, one per nest. The female mimics a sparrowhawk
Sparrowhawk (sometimes sparrow hawk) may refer to several species of small hawk in the genus ''Accipiter''. "Sparrow-hawk" or sparhawk originally referred to ''Eurasian sparrowhawk, Accipiter nisus'', now called "Eurasian" or "northern" sparrowha ...
. The resemblance is sufficient to make small birds take action to avoid the apparent predator. The female cuckoo then has time to lay her egg in their nest without being seen to do so. The cuckoo's egg itself mimics the eggs of the host species, reducing its chance of being rejected.
File:Biston betularia.png, Peppered moth
The peppered moth (''Biston betularia'') is a temperate species of night-flying moth. It is mostly found in the northern hemisphere in places like Asia, Europe and North America. Peppered moth evolution is an example of population genetics an ...
caterpillars mimic twigs
File:Insect camouflage PP08338.png, Flower mantis
Flower mantises are praying mantis species that use a special form of camouflage referred to as aggressive mimicry, which they not only use to attract prey, but avoid predators as well. These insects have specific colorations and behaviors that ...
lures its insect prey by mimicking a ''Phalaenopsis
''Phalaenopsis'' (), also known as moth orchids, is a genus of about seventy species of plants in the family Orchidaceae. Orchids in this genus are monopodial epiphytes or lithophytes with long, coarse roots, short, leafy stems and long-lasting ...
'' orchid blossom
File:Hooded Grasshopper (Teratodus monticollis) W IMG 0525.jpg, Hooded grasshopper ''Teratodus monticollis'', superbly mimics a leaf with a bright orange border
File:Gumleaf grasshopper.jpg, This grasshopper
Grasshoppers are a group of insects belonging to the suborder Caelifera. They are among what is possibly the most ancient living group of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago.
Grasshopp ...
hides from predators by mimicking a dry leaf
File:IWM-E-18461-Crusader-camouflaged-19421026.jpg, WWII tank
A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engin ...
concealed in Operation Bertram
Operation Bertram was a Second World War deception operation practised by the Allied forces in Egypt led by Bernard Montgomery, in the months before the Second Battle of El Alamein in 1942. Bertram was devised by Dudley Clarke to deceive Erwin R ...
by mimicking a truck
A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construction ...
File:HMS President - geograph.org.uk - 659583.jpg, Armed WW1 Q-ship
Q-ships, also known as Q-boats, decoy vessels, special service ships, or mystery ships, were heavily armed merchant ships with concealed weaponry, designed to lure submarines into making surface attacks. This gave Q-ships the chance to open f ...
lured enemy submarines by mimicking a merchantman
A merchant ship, merchant vessel, trading vessel, or merchantman is a watercraft that transports cargo or carries passengers for hire. This is in contrast to pleasure craft, which are used for personal recreation, and naval ships, which are u ...
File:European Cuckoo Mimics Sparrowhawk.jpg, Cuckoo
Cuckoos are birds in the Cuculidae family, the sole taxon in the order Cuculiformes . The cuckoo family includes the common or European cuckoo, roadrunners, koels, malkohas, couas, coucals and anis. The coucals and anis are sometimes separ ...
adult mimics sparrowhawk
Sparrowhawk (sometimes sparrow hawk) may refer to several species of small hawk in the genus ''Accipiter''. "Sparrow-hawk" or sparhawk originally referred to ''Eurasian sparrowhawk, Accipiter nisus'', now called "Eurasian" or "northern" sparrowha ...
, giving female time to lay eggs parasitically
File:Cuckoo Eggs Mimicking Reed Warbler Eggs.JPG, Cuckoo eggs mimicking smaller eggs, in this case of reed warbler
The ''Acrocephalus'' warblers are small, insectivorous passerine birds belonging to the genus ''Acrocephalus''. Formerly in the paraphyletic Old World warbler assemblage, they are now separated as the namesake of the marsh and tree warbler famil ...
File:Wrap-around spider in the genus Dolophones (Family Araneidae) Camouflage View.JPG, Wrap-around spider ''Dolophones'' mimicking a stick
Motion dazzle
Most forms of camouflage are made ineffective by movement: a deer or grasshopper may be highly cryptic when motionless, but instantly seen when it moves. But one method, motion dazzle, requires rapidly moving bold patterns of contrasting stripes.[ Motion dazzle may degrade predators' ability to estimate the prey's speed and direction accurately, giving the prey an improved chance of escape.] Motion dazzle distorts speed perception and is most effective at high speeds; stripes can also distort perception of size (and so, perceived range to the target). As of 2011, motion dazzle had been proposed for military vehicles, but never applied. Since motion dazzle patterns would make animals more difficult to locate accurately when moving, but easier to see when stationary, there would be an evolutionary trade-off between motion dazzle and crypsis.[
An animal that is commonly thought to be dazzle-patterned is the ]zebra
Zebras (, ) (subgenus ''Hippotigris'') are African equines with distinctive black-and-white striped coats. There are three living species: the Grévy's zebra (''Equus grevyi''), plains zebra (''E. quagga''), and the mountain zebra (''E. zeb ...
. The bold stripes of the zebra have been claimed to be disruptive camouflage, background-blending and countershading. After many years in which the purpose of the coloration was disputed, an experimental study by Tim Caro Timothy M. Caro (born 1951) is a British evolutionary ecologist known for his work on conservation biology, animal behaviour, anti-predator defences in animals, and the function of zebra stripes. He is the author of several textbooks on these su ...
suggested in 2012 that the pattern reduces the attractiveness of stationary models to biting flies such as horseflies and tsetse flies
Tsetse ( , or ) (sometimes spelled tzetze; also known as tik-tik flies), are large, biting flies that inhabit much of tropical Africa. Tsetse flies include all the species in the genus ''Glossina'', which are placed in their own family, Glo ...
. However, a simulation study by Martin How and Johannes Zanker in 2014 suggests that when moving, the stripes may confuse observers, such as mammalian predators and biting insects, by two visual illusion
Within visual perception, an optical illusion (also called a visual illusion) is an illusion caused by the visual system and characterized by a visual percept that arguably appears to differ from reality. Illusions come in a wide variety; thei ...
s: the wagon-wheel effect
The wagon-wheel effect (alternatively called stagecoach-wheel effect or stroboscopic effect) is an optical illusion in which a spoked wheel appears to rotate differently from its true rotation. The wheel can appear to rotate more slowly than the ...
, where the perceived motion is inverted, and the barberpole illusion
The barberpole illusion is a visual illusion that reveals biases in the processing of visual motion in the human brain. This visual illusion occurs when a diagonally striped pole is rotated around its vertical axis (horizontally), it appears as th ...
, where the perceived motion is in a wrong direction.
Applications
Military
Before 1800
Ship camouflage was occasionally used in ancient times. Philostratus
Philostratus or Lucius Flavius Philostratus (; grc-gre, Φιλόστρατος ; c. 170 – 247/250 AD), called "the Athenian", was a Greek sophist of the Roman imperial period. His father was a minor sophist of the same name. He was born probab ...
() wrote in his '' Imagines'' that Mediterranean pirate ships could be painted blue-gray for concealment. Vegetius
Publius (or Flavius) Vegetius Renatus, known as Vegetius (), was a writer of the Later Roman Empire (late 4th century). Nothing is known of his life or station beyond what is contained in his two surviving works: ''Epitoma rei militaris'' (also re ...
() says that "Venetian blue" (sea green) was used in the Gallic Wars
The Gallic Wars were waged between 58 and 50 BC by the Roman general Julius Caesar against the peoples of Gaul (present-day France, Belgium, Germany and Switzerland). Gallic, Germanic, and British tribes fought to defend their homela ...
, when Julius Caesar
Gaius Julius Caesar (; ; 12 July 100 BC – 15 March 44 BC), was a Roman general and statesman. A member of the First Triumvirate, Caesar led the Roman armies in the Gallic Wars before defeating his political rival Pompey in a civil war, and ...
sent his ''speculatoria navigia'' (reconnaissance boats) to gather intelligence along the coast of Britain; the ships were painted entirely in bluish-green wax, with sails, ropes and crew the same colour. There is little evidence of military use of camouflage on land before 1800, but two unusual ceramics show men in Peru
, image_flag = Flag of Peru.svg
, image_coat = Escudo nacional del Perú.svg
, other_symbol = Great Seal of the State
, other_symbol_type = Seal (emblem), National seal
, national_motto = "Fi ...
's Mochica
The Moche civilization (; alternatively, the Mochica culture or the Early, Pre- or Proto-Chimú) flourished in northern Peru with its capital near present-day Moche, Trujillo, Peru from about 100 to 700 AD during the Regional Development Epoch. ...
culture from before 500 AD, hunting birds with blowpipes which are fitted with a kind of shield near the mouth, perhaps to conceal the hunters' hands and faces. Another early source is a 15th-century French manuscript, ''The Hunting Book of Gaston Phebus'', showing a horse pulling a cart which contains a hunter armed with a crossbow under a cover of branches, perhaps serving as a hide for shooting game. Jamaican Maroons
Jamaican Maroons descend from Africans who freed themselves from slavery on the Colony of Jamaica and established communities of free black people in the island's mountainous interior, primarily in the eastern parishes. Africans who were ensla ...
are said to have used plant materials as camouflage in the First Maroon War
The First Maroon War was a conflict between the Jamaican Maroons and the colonial British authorities that started around 1728 and continued until the peace treaties of 1739 and 1740. It was led by self-liberated Africans who set up communities in ...
().
19th-century origins
The development of military camouflage was driven by the increasing range and accuracy of infantry firearms in the 19th century. In particular the replacement of the inaccurate musket
A musket is a muzzle-loaded long gun that appeared as a smoothbore weapon in the early 16th century, at first as a heavier variant of the arquebus, capable of penetrating plate armour. By the mid-16th century, this type of musket gradually d ...
with weapons such as the Baker rifle
The Baker rifle (officially known as the Pattern 1800 Infantry Rifle) was a flintlock rifle used by the rifle regiments of the British Army during the Napoleonic Wars. It was the first standard-issue, British-made rifle accepted by the British ...
made personal concealment in battle essential. Two Napoleonic War
The Napoleonic Wars (1803–1815) were a series of major global conflicts pitting the French Empire and its allies, led by Napoleon I, against a fluctuating array of European states formed into various coalitions. It produced a period of Fren ...
skirmishing units of the British Army
The British Army is the principal land warfare force of the United Kingdom, a part of the British Armed Forces along with the Royal Navy and the Royal Air Force. , the British Army comprises 79,380 regular full-time personnel, 4,090 Gurk ...
, the 95th Rifle Regiment and the 60th Rifle Regiment, were the first to adopt camouflage in the form of a rifle green
Shades of chartreuse are listed below. Historically, many of these colors have gone under the name of either yellow or green, as the specifics of their color composition was not known until later.
Wrapping the spectrum into a color wheel
In a ...
jacket, while the Line regiments continued to wear scarlet tunics. A contemporary study in 1800 by the English artist and soldier Charles Hamilton Smith
Lieutenant-Colonel Charles Hamilton Smith, KH, KW, FRS, FLS, (26 December 1776 in East Flanders, in the United Provinces of the Netherlands – 21 September 1859 in Plymouth) was an English artist, naturalist, antiquary, illustrator, soldie ...
provided evidence that grey uniforms were less visible than green ones at a range of 150 yards.
In the American Civil War
The American Civil War (April 12, 1861 – May 26, 1865; also known by other names) was a civil war in the United States. It was fought between the Union ("the North") and the Confederacy ("the South"), the latter formed by states th ...
, rifle units such as the 1st United States Sharp Shooters (in the Federal
Federal or foederal (archaic) may refer to:
Politics
General
*Federal monarchy, a federation of monarchies
*Federation, or ''Federal state'' (federal system), a type of government characterized by both a central (federal) government and states or ...
army) similarly wore green jackets while other units wore more conspicuous colours. The first British Army unit to adopt khaki
The color khaki (, ) is a light shade of tan with a slight yellowish tinge.
Khaki has been used by many armies around the world for uniforms and equipment, particularly in arid or desert regions, where it provides camouflage relative to sandy ...
uniforms was the Corps of Guides at Peshawar
Peshawar (; ps, پېښور ; hnd, ; ; ur, ) is the sixth most populous city in Pakistan, with a population of over 2.3 million. It is situated in the north-west of the country, close to the International border with Afghanistan. It is ...
, when Sir Harry Lumsden and his second in command, William Hodson introduced a "drab" uniform in 1848. Hodson wrote that it would be more appropriate for the hot climate, and help make his troops "invisible in a land of dust". Later they improvised by dyeing cloth locally. Other regiments in India soon adopted the khaki uniform, and by 1896 khaki drill
Khaki drill (KD) is the British military term for a type of fabric and the military uniforms made from them.
History
Khaki colour uniforms were first introduced in 1848 in the British Indian Army Corps of Guides. As well as the Corps of Guid ...
uniform was used everywhere outside Europe; by the Second Boer War
The Second Boer War ( af, Tweede Vryheidsoorlog, , 11 October 189931 May 1902), also known as the Boer War, the Anglo–Boer War, or the South African War, was a conflict fought between the British Empire and the two Boer Republics (the Sout ...
six years later it was used throughout the British Army.
During the late 19th century camouflage was applied to British coastal fortifications. The fortifications around Plymouth, England were painted in the late 1880s in "irregular patches of red, brown, yellow and green." From 1891 onwards British coastal artillery was permitted to be painted in suitable colours "to harmonise with the surroundings" and by 1904 it was standard practice that artillery and mountings should be painted with "large irregular patches of different colours selected to suit local conditions."
First World War
In the First World War
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, the French army formed a camouflage corps, led by Lucien-Victor Guirand de Scévola
Lucien-Victor Guirand de Scévola (14 November 1871 in Sète, France – 29 March 1950 in Paris) was a French painter. He is known for his pioneering leadership of the ''Camoufleurs'' (the French Camouflage Department) in World War I.
Early l ...
, employing artists known as ''camoufleurs
A camoufleur or camouflage officer is a person who designed and implemented military camouflage in one of the world wars of the twentieth century. The term originally meant a person serving in a First World War French military camouflage unit. In ...
'' to create schemes such as tree observation posts and covers for guns. Other armies soon followed them. The term ''camouflage
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the ...
'' probably comes from ''camoufler'', a Paris
Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...
ian slang term meaning ''to disguise'', and may have been influenced by ''camouflet'', a French term meaning ''smoke blown in someone's face''. The English zoologist John Graham Kerr
Sir John Graham Kerr (18 September 1869 – 21 April 1957), known to his friends as Graham Kerr, was a British embryologist and Unionist Member of Parliament (MP). He is best known for his studies of the embryology of lungfishes. He was involv ...
, artist Solomon J. Solomon and the American artist Abbott Thayer led attempts to introduce scientific principles of countershading and disruptive patterning into military camouflage, with limited success. In early 1916 the Royal Naval Air Service
The Royal Naval Air Service (RNAS) was the air arm of the Royal Navy, under the direction of the Admiralty's Air Department, and existed formally from 1 July 1914 to 1 April 1918, when it was merged with the British Army's Royal Flying Corps t ...
began to create dummy air fields to draw the attention of enemy planes to empty land. They created decoy homes and lined fake runways with flares, which were meant to help protect real towns from night raids. This strategy was not common practice and did not succeed at first, but in 1918 it caught the Germans off guard multiple times.
Ship camouflage
Ship camouflage is a form of military deception in which a ship is painted in one or more colors in order to obscure or confuse an enemy's visual observation. Several types of marine camouflage have been used or prototyped: blending or crypsis, ...
was introduced in the early 20th century as the range of naval guns increased, with ships painted grey all over.[ In April 1917, when German ]U-boats
U-boats were naval submarines operated by Germany, particularly in the First and Second World Wars. Although at times they were efficient fleet weapons against enemy naval warships, they were most effectively used in an economic warfare rol ...
were sinking many British ships with torpedoes, the marine artist Norman Wilkinson devised dazzle camouflage
Dazzle camouflage, also known as razzle dazzle (in the U.S.) or dazzle painting, is a family of ship camouflage that was used extensively in World War I, and to a lesser extent in World War II and afterwards. Credited to the British marine ar ...
, which paradoxically made ships more visible but harder to target. In Wilkinson's own words, dazzle was designed "not for low visibility, but in such a way as to break up her form and thus confuse a submarine officer as to the course on which she was heading".
File:USS West Mahomet (ID-3681) cropped.jpg, USS ''West Mahomet'' in dazzle camouflage
File:CamouflagedAustralian9.2inchHowitzerYpres1917.jpeg, Siege howitzer
A siege is a military blockade of a city, or fortress, with the intent of conquering by attrition, or a well-prepared assault. This derives from la, sedere, lit=to sit. Siege warfare is a form of constant, low-intensity conflict characterize ...
camouflaged against observation from the air, 1917
File:Austro-Hungarian ski patrol on Italian front in snow camouflage 1915-1918.jpg, Austro-Hungarian ski patrol in two-part snow uniforms with improvised head camouflage on Italian front, 1915-1918
Second World War
In the Second World War
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, the zoologist Hugh Cott, a protégé
Mentorship is the influence, guidance, or direction given by a mentor. A mentor is someone who teaches or gives help and advice to a less experienced and often younger person. In an organizational setting, a mentor influences the personal and p ...
of Kerr, worked to persuade the British army to use more effective camouflage methods, including countershading, but, like Kerr and Thayer in the First World War, with limited success. For example, he painted two rail-mounted coastal guns, one in conventional style, one countershaded
Countershading, or Thayer's law, is a method of camouflage in which an animal's coloration is darker on the top or upper side and lighter on the underside of the body. This pattern is found in many species of mammals, reptiles, birds, fish, and ...
. In aerial photographs, the countershaded gun was essentially invisible. The power of aerial observation and attack led every warring nation to camouflage targets of all types. The Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...
's Red Army
The Workers' and Peasants' Red Army (Russian: Рабо́че-крестья́нская Кра́сная армия),) often shortened to the Red Army, was the army and air force of the Russian Soviet Federative Socialist Republic and, after ...
created the comprehensive doctrine
Doctrine (from la, doctrina, meaning "teaching, instruction") is a codification of beliefs or a body of teachings or instructions, taught principles or positions, as the essence of teachings in a given branch of knowledge or in a belief system ...
of ''Maskirovka
Russian military deception, sometimes known as ''maskirovka'' (russian: маскировка, lit=disguise), is a military doctrine developed from the start of the 20th century. The doctrine covers a broad range of measures for military deceptio ...
'' for military deception, including the use of camouflage. For example, during the Battle of Kursk
The Battle of Kursk was a major World War II Eastern Front engagement between the forces of Nazi Germany and the Soviet Union near Kursk in the southwestern USSR during late summer 1943; it ultimately became the largest tank battle in history. ...
, General Katukov, the commander of the Soviet 1st Tank Army, remarked that the enemy "did not suspect that our well-camouflaged tanks were waiting for him. As we later learned from prisoners, we had managed to move our tanks forward unnoticed". The tanks were concealed in previously prepared defensive emplacements, with only their turrets above ground level. In the air, Second World War fighters were often painted in ground colours above and sky colours below, attempting two different camouflage schemes for observers above and below. Bombers and night fighters were often black, while maritime reconnaissance planes were usually white, to avoid appearing as dark shapes against the sky. For ships, dazzle camouflage was mainly replaced with plain grey in the Second World War, though experimentation with colour schemes continued.[
As in the First World War, artists were pressed into service; for example, the surrealist painter ]Roland Penrose
Sir Roland Algernon Penrose (14 October 1900 – 23 April 1984) was an English artist, historian and poet. He was a major promoter and collector of modern art and an associate of the surrealists in the United Kingdom. During the Second World W ...
became a lecturer at the newly founded Camouflage Development and Training Centre at Farnham Castle
Farnham Castle is a 12th-century castle in Farnham, Surrey, England. It was formerly the residence of the Bishops of Winchester.
History
Built in 1138 by Henri de Blois, Bishop of Winchester, grandson of William the Conqueror, Farnham cast ...
, writing the practical ''Home Guard Manual of Camouflage''. The film-maker Geoffrey Barkas
Geoffrey Barkas (born Geoffrey de Gruchy Barkas, 27 August 1896 – 3 September 1979) was an English film maker active between the world wars.
Barkas led the British Middle East Command Camouflage Directorate in the Second World War. His larges ...
ran the Middle East Command Camouflage Directorate
The British Middle East Command Camouflage Directorate (also known as the Camouflage Unit or Camouflage Branch) organised major deception operations for Middle East Command in the Western Desert Campaign of the Second World War. It provided camo ...
during the 1941–1942 war in the Western Desert, including the successful deception of Operation Bertram
Operation Bertram was a Second World War deception operation practised by the Allied forces in Egypt led by Bernard Montgomery, in the months before the Second Battle of El Alamein in 1942. Bertram was devised by Dudley Clarke to deceive Erwin R ...
. Hugh Cott was chief instructor; the artist camouflage officers, who called themselves ''camoufleurs
A camoufleur or camouflage officer is a person who designed and implemented military camouflage in one of the world wars of the twentieth century. The term originally meant a person serving in a First World War French military camouflage unit. In ...
'', included Steven Sykes and Tony Ayrton
Antony Maxwell Ayrton (1909 – 4 April 1943) known as Tony Ayrton, was an artist and Camoufleurs, camouflage officer. He is best known for his work on the large-scale Military deception, deception for the decisive second battle of El Alamein, ...
. In Australia, artists were also prominent in the Sydney Camouflage Group, formed under the chairmanship of Professor William John Dakin
William John Dakin (23 July 1883 – 2 April 1950) was a zoology, zoologist who is remembered for the large number of his students who achieved prominence in the area of zoology and for the number of books and papers he wrote on many scientific f ...
, a zoologist from Sydney University. Max Dupain
Maxwell Spencer Dupain AC OBE (22 April 191127 July 1992) was an Australian modernist photographer.
Early life
Dupain received his first camera as a gift in 1924, spurring his interest in photography. He later joined the Photographic Society ...
, Sydney Ure Smith
Sydney George Ure Smith OBE (9 January 188711 October 1949) was an Australian arts publisher, artist and promoter who "did more than any other Australian to publicize Australian art at home and overseas".
Unlike most of his contemporaries, he ...
, and William Dobell
Sir William Dobell (24 September 189913 May 1970) was an Australian portrait and landscape artist of the 20th century. Dobell won the Archibald Prize, Australia's premier award for portrait artists on three occasions. The Dobell Prize is named ...
were among the members of the group, which worked at Bankstown Airport
Bankstown Airport is an airport and business park located in the City of Canterbury-Bankstown, approximately from the Sydney Central Business District (CBD), Australia and west of Sydney Airport. It is situated on of land and has three paral ...
, RAAF Base Richmond
RAAF Base Richmond is a Royal Australian Air Force (RAAF) military air base located within the City of Hawkesbury, approximately North-West of the Sydney Central Business District in New South Wales, Australia. Situated between the towns of W ...
and Garden Island Dockyard. In the United States, artists like John Vassos
John Vassos (born John Plato Vassacopoulos; 23 October 1898 – 6 December 1985) whose career as an American industrial designer and artist helped define the shape of radio, television, broadcasting equipment, and computers for the Radio Corpora ...
took a certificate course in military and industrial camouflage at the American School of Design with Baron Nicholas Cerkasoff, and went on to create camouflage for the Air Force.
File:Catalina Góraszka 2008 204.JPG, Maritime patrol Catalina
Catalina may refer to:
Arts and media
* ''The Catalina'', a 2012 American reality television show
* ''Catalina'' (novel), a 1948 novel by W. Somerset Maugham
* Catalina (''My Name Is Earl''), character from the NBC sitcom ''My Name Is Earl''
...
, painted white to minimise visibility against the sky
File:SS Platanenmuster Sommer.jpg, 1937 summer variant of Waffen SS
The (, "Armed SS") was the combat branch of the Nazi Party's ''Schutzstaffel'' (SS) organisation. Its formations included men from Nazi Germany, along with volunteers and conscripts from both occupied and unoccupied lands.
The grew from th ...
''Flecktarn
''Flecktarn'' (; "mottled camouflage"; also known as ''Flecktarnmuster'' or ''Fleckentarn'') is a family of 3-, 4-, 5- or 6-color disruptive camouflage patterns, the most common being the five-color pattern, consisting of dark green, light green ...
'' Plane tree pattern
File:USS Duluth (CL-87) underway in Hampton Roads on 10 October 1944 (NH 98363).jpg, USS ''Duluth'' in naval camouflage Measure 32, Design 11a, one of many dazzle schemes used on warships
File:Spitfire.planform.arp.jpg, A Spitfire's underside 'azure' paint scheme, meant to hide it against the sky
File:Royal Air Force 1939-1945- Fighter Command CL3979.jpg, A Luftwaffe
The ''Luftwaffe'' () was the aerial-warfare branch of the German ''Wehrmacht'' before and during World War II. Germany's military air arms during World War I, the ''Luftstreitkräfte'' of the Imperial Army and the '' Marine-Fliegerabtei ...
aircraft hangar built to resemble a street of village houses, Belgium, 1944
File:Bundesarchiv Bild 183-E0406-0022-001, Russland, Kesselschlacht Stalingrad.jpg, Red Army
The Workers' and Peasants' Red Army (Russian: Рабо́че-крестья́нская Кра́сная армия),) often shortened to the Red Army, was the army and air force of the Russian Soviet Federative Socialist Republic and, after ...
soldiers in the Battle of Stalingrad
The Battle of Stalingrad (23 August 19422 February 1943) was a major battle on the Eastern Front of World War II where Nazi Germany and its allies unsuccessfully fought the Soviet Union for control of the city of Stalingrad (later re ...
in snow camouflage
Snow camouflage is the use of a coloration or pattern for effective camouflage in winter, often combined with a different summer camouflage. Summer patterns are typically disruptively patterned combinations of shades of browns and greys, up to ...
overalls, January 1943
After 1945
Camouflage has been used to protect military equipment such as vehicles, guns, ships
A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished ...
, aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines ...
and buildings as well as individual soldiers and their positions.
Vehicle camouflage methods begin with paint, which offers at best only limited effectiveness. Other methods for stationary land vehicles include covering with improvised materials such as blankets and vegetation, and erecting nets, screens and soft covers which may suitably reflect, scatter or absorb near infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
and radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
waves. Some military textiles and vehicle camouflage paints also reflect infrared to help provide concealment from night vision
Night vision is the ability to see in low-light conditions, either naturally with scotopic vision or through a night-vision device. Night vision requires both sufficient spectral range and sufficient intensity range. Humans have poor night vi ...
devices.
After the Second World War, radar made camouflage generally less effective, though coastal boats are sometimes painted like land vehicles.[ ]Aircraft camouflage
Aircraft camouflage is the use of camouflage on military aircraft to make them more difficult to see, whether on the ground or in the air. Given the possible backgrounds and lighting conditions, no single scheme works in every situation. A comm ...
too came to be seen as less important because of radar, and aircraft of different air forces, such as the Royal Air Force's Lightning
Lightning is a naturally occurring electrostatic discharge during which two electric charge, electrically charged regions, both in the atmosphere or with one on the land, ground, temporarily neutralize themselves, causing the instantaneous ...
, were often uncamouflaged.
Many camouflaged textile patterns have been developed to suit the need to match combat clothing to different kinds of terrain (such as woodland, snow, and desert). The design of a pattern effective in all terrains has proved elusive. The American Universal Camouflage Pattern
The Universal Camouflage Pattern (UCP) is a digital military camouflage pattern formerly used by the United States Army in their Army Combat Uniform. Technicians at Natick Soldier Systems Center attempted to devise a uniform pattern that wou ...
of 2004 attempted to suit all environments, but was withdrawn after a few years of service. Terrain-specific patterns have sometimes been developed but are ineffective in other terrains. The problem of making a pattern that works at different ranges has been solved with multiscale designs, often with a pixellated appearance and designed digitally, that provide a fractal
In mathematics, a fractal is a geometric shape containing detailed structure at arbitrarily small scales, usually having a fractal dimension strictly exceeding the topological dimension. Many fractals appear similar at various scales, as illu ...
-like range of patch sizes so they appear disruptively coloured both at close range and at a distance. The first genuinely digital camouflage pattern was the Canadian Disruptive Pattern (CADPAT
Canadian Disruptive Pattern (CADPAT; french: links=no, dessin de camouflage canadien, DcamC) is the computer-generated digital camouflage pattern developed for use by the Canadian Armed Forces. Four operational variations of CADPAT have been used ...
), issued to the army in 2002, soon followed by the American Marine pattern (MARPAT
MARPAT (short for Marine pattern) is a multi-scale camouflage pattern in use with the United States Marine Corps, designed in 2001 and introduced from late 2002 to early 2005 with the Marine Corps Combat Utility Uniform (MCCUU), which replaced ...
). A pixellated appearance is not essential for this effect, though it is simpler to design and to print.
File:CADPAT digital camouflage pattern (Temperate Woodland variant).jpg, CADPAT
Canadian Disruptive Pattern (CADPAT; french: links=no, dessin de camouflage canadien, DcamC) is the computer-generated digital camouflage pattern developed for use by the Canadian Armed Forces. Four operational variations of CADPAT have been used ...
was the first pixellated
In computer graphics, pixelation (or pixellation in British English) is caused by displaying a bitmap or a section of a bitmap at such a large size that individual pixels, small single-colored square display elements that comprise the bitmap, a ...
digital camouflage
Multi-scale camouflage is a type of military camouflage combining patterns at two or more scales, often (though not necessarily) with a digital camouflage pattern created with computer assistance. The function is to provide camouflage over a ra ...
pattern to be issued, in 2002.
File:British dpm2.jpg, British Disruptive Pattern Material
Disruptive Pattern Material (DPM) is the commonly used name of a camouflage pattern used by the British Armed Forces as well as many other armed forces worldwide, particularly in former British colonies.
The main variants of DPM are a four-col ...
, issued to special forces
Special forces and special operations forces (SOF) are military units trained to conduct special operations. NATO has defined special operations as "military activities conducted by specially designated, organized, selected, trained and equip ...
in 1963 and universally by 1968
File:M05 snow pattern.jpg, 2007 2-colour snow variant of Finnish Defence Forces
The Finnish Defence Forces ( fi, Puolustusvoimat, sv, Försvarsmakten) are the military of Finland. The Finnish Defence Forces consist of the Finnish Army, the Finnish Navy and the Finnish Air Force. In wartime the Finnish Border Guard (which i ...
M05 pattern
File:Pla camo.svg, Main (4-colour woodland) variant of Chinese People's Liberation Army
The People's Liberation Army (PLA) is the principal military force of the People's Republic of China and the armed wing of the Chinese Communist Party (CCP). The PLA consists of five service branches: the Ground Force, Navy, Air Force, ...
Type 99 pattern, c. 2006