Animal Camouflage Trivia Quiz

Answer: chromatophores

In ectothermic (cold-blooded) animals, the cells responsible for eye and skin colour are called cromatophores ("colour-bearers" in Greek). Generated in the neural crest during embryonic development, they are classified according to their colour under white light: melanophores (black/brown), erythrophores (red), xantophores (yellow), cyanophores (blue), leucophores (white), and iridophores (iridescent/reflective). Cromatophores contain biochromes (biological pigments) such as carotenoids, responsible for the red or orange colouration of some crustaceans. The word was coined in 1819 by Italian zoologist Giosuč Sangiovanni.

Pigment-bearing cells in mammals and birds - which are endothermic (warm-blooded) animals - are called chromatocytes. Only one class of chromatocytes has been identified - that of melanocytes, which are located in the bottom layer of the epidermis. In humans, mammals and birds, melanin (a broad term for the group of pigments contained in melanocytes) is responsible for the colour of skin, hair, fur, feathers, and eyes.

The bright violet stripe of the fish in the photo, known as diadem dottyback (Pictichromis diadema), is generated by atypical chromatophores - named erythro-iridophores - that contain two different pigments instead of one, as is the norm.

Answer: its environment

The simplest and most common camouflage technique is background adaptation - when an animal's colouration matches a particular natural background. Desert-dwelling animals tend to be various shades of sand, ochre, tan, and brownish-grey - which helps them blend more effectively with their arid surroundings. On the other hand, many tree-dwelling birds, especially in tropical areas, have green plumage (like the parakeet in the photo). Animals that live in forests at ground level are often brown, matching the colour of the soil, while some insect species have mottled bodies or wings that are often virtually indistinguishable from tree bark.

Background adaptation also works underwater. For example, a number of freshwater fish species, such as the brown trout, have speckled bodies that resemble the pebbles on riverbeds.

While quite widespread, background matching is only one of the many camouflage strategies employed by animals either to hunt or hide from predators. Most of these strategies have also been adopted by humans for military purposes.

Answer: changing seasons

Snow camouflage is a kind of active camouflage - the ability to adapt rapidly to one's surroundings to avoid detection - that involves changing colour with the changing of the seasons. With the arrival of winter, a number of Arctic and subarctic animals change their brown coats to white to match their snow-covered surroundings. Most of these species are mammals, such as the Arctic fox (shown in the photo), the Arctic hare, and the stoat (known as ermine when in its winter coat). The rock ptarmigan is the only bird species that adopts snow camouflage at the beginning of the winter season. This change in colour is achieved by the animal moulting and growing new fur or feathers.

Interestingly, in the spring and summer these animals are also adapted to their surroundings for camouflage, as their coats or plumage are brown or grey. On the other hand, some species that live north of the Arctic Circle - such as the Arctic wolf, the polar bear, or the snowy owl - remain white all year round, while others - such as muskoxen or reindeer - never became white at all, even in the coldest parts of their range.

Answer: octopus

The form of active camouflage practiced by chameleons and cephalopods (octopus, squid, and cuttlefish), as well as some species of flatfish (notably the peacock flounder) and frogs, entails being able to change colour in a matter of seconds thanks to complex mechanisms that activate the chromatophores in their skin. Chameleons can produce a wide range of colours and patterns, but they do this primarily for social signalling purposes (that is, to express mood) or to react to changes in temperature, rather than to blend in with different backgrounds. However, chameleons are also chromatically adapted to their environment, as tree-dwelling species (such as the veiled chameleon in the photo) tend to have brighter colours than those that live in arid or semi-arid regions.

Cephalopods use active camouflage for hunting and avoiding predators, as well as communication. The chromatophores in these animals' skins are controlled by the brain, and are believed to be able to detect changing light conditions and adjust to them independently of vision input. Some octopus species are able to change skin texture, while others create waves of dark colour across the body known as "passing cloud". The notorious blue-ringed octopus, one of the most venomous animals on Earth, gets its name from the iridescent blue rings that dot its mantle, which the animal flashes as a warning display by contracting its muscular skin folds.

Answer: leopard

Military camouflage often employs disruptive colouration (also known as disruptive patterning), which is based on a somewhat counterintuitive principle - the use of high-contrast patterns to break up the outline of a person, animal, or vehicle. According to British zoologist Hugh Cott, bold patterns of light and dark disrupt the perception of outlines and details, as the eye is drawn to those patches of colour and away from the shape as a whole.

In nature, both predators and prey use disruptive colouration such as stripes or spots. The spotted coats of leopards, jaguars and cheetahs, or the striped coats of tigers, are effective at making the animals less conspicuous in areas with patchy vegetation or tall grass, so that their outline is not recognizable. On the other hand, the bold patterns of giraffes can make them conspicuous in open spaces, but instead conceal them when standing among trees and bushes.

Another variation on disruptive patterning is the disruptive eye mask sported by many animal species, which conceals the easy-to-spot, circular outline of the eyes. Some animals, especially fish, combine the concealing eyestripe with eye-like markings (eyespots) on other parts of the body, which can give a predator the impression that the head is located there. A phenomenon called "motion dazzle" also has some similarities to disruptive colouration. It refers to the visual confusion generated by a rapidly moving pattern of contrasting stripes - such as those of zebras running away from predators in the savanna.

Answer: it flattens the animal's body when viewed from above

Also known as Thayer's Law (from the name of American artist and naturalist Abbot Thayer, who wrote about animal camouflage), countershading consists in an animal having different colour shades for its back and belly. When viewed from above or from the side, the animal's body looks two-dimensional, and may also "disappear" into the background. If turned upside down, a countershaded animal would become highly conspicuous, as the light would fall on its lighter-coloured side, emphasizing its three-dimensional shape.

Countershading is an especially important camouflage method for marine animals, such as dolphins and various shark species. Penguins, which are excellent swimmers, are sharply countershaded, with dark backs and flippers and white fronts. If viewed from above when swimming (as in the case of the Humboldt penguins in the photo), the birds' dark upper sides would make their bodies look flat, and eventually blend with the dark depths of the sea. If one of their habitual predators - such as an orca or a leopard seal - viewed them from below, the penguin's white belly would be hard to distinguish from the reflective water surface.

Some mammal species, especially ungulates such as deer and antelope - frequently targeted by predators (including humans) - are also countershaded, which makes them nearly invisible against a suitable background.

Answer: thick fur

If the purpose of camouflage is making an animal as inconspicuous as possible, aposematism is its polar opposite - being based on a rather blatant advertising strategy. As its name implies (meaning more or less "away-signalling" in Greek), aposematism consists in giving mainly visual signals to potential predators, warning them that an animal is an unsuitable or even dangerous prey. It is, therefore, as much of a defense from possible attacks as camouflage.

The most typical form of aposematism is the use of bright colours to signal an animal's toxicity. This is the strategy used by poison dart frogs such as the one in the photo, as these small tropical amphibians have extremely poisonous skin. The red dorsal markings of black widow spiders are also believed to be aposematic, as are the vividly coloured carapaces of some beetles (such as ladybugs) that contain bitter-tasting chemicals. Marine animals combine warning colouration with other strategies, such as sharp spines: examples of this are the venomous red lionfish (Pterois volitans) and the crow-of-thorns starfish. In mammals, black-and-white patterned fur often advertises the presence of scent glands dispensing foul-smelling substances (as in skunks), or an aggressive disposition and sharp claws (as in badgers and honey badgers).

While a thick layer of fur provides plenty of protection against the elements and vegetation, it does not advertise an animal's unsuitability as prey.

Answer: mimicry

Mimicry (from the Greek word for "imitative") is a different approach than ordinary camouflage, but it works toward the same end. By developing a certain appearance, an animal species makes itself a harder target for predators or a sneakier hunter for prey. A very common phenomenon in the animal world, mimicry can be either defensive, offensive, or reproductive, and comes in a number of different variations - named after the naturalists who studied them.

A well-known example of defensive mimicry is found in some non-venomous snakes of the genus Lampropeltis (such as the scarlet kingsnake depicted in the photo), whose striking colour patterns mimic those of the deadly coral snake (Micrurus sp.) - hence the common (though somewhat unreliable) mnemonics "red on yellow kill a fellow, red on black venom lack", and variations thereof. This is a form of Batesian mimicry, in which the resemblance of a harmless species to a harmful one frightens off potential predators: as such, it has sometimes been referred to as "sheep in wolf's clothing". Another example of Batesian mimicry is insects such as hoverflies and wasp beetles, whose colours mimic those of stinging wasps.

Answer: leafy seadragon

While the term "mimicry" is used for animals that imitate the appearance of other animal species, imitating natural objects such as twigs, flowers, or rocks is often referred to as "mimesis" or "masquerade". One of the most famous examples of mimesis is seen in stick insects (family Phasmatodea), which look like twigs or leaves. Flower mantises, on the other hand, look like various flower species - especially orchids - to attract bees and other pollinator insects, which are their main prey. You can also see this kind of camouflage in some katydid species, which have evolved so that they look just like tree leaves.

Some marine animals have also adopted mimesis as an effective form of camouflage against predators. The body of the leafy seadragon (Phycodurus eques), a close relative of the seahorse, is covered by long, leaf-like flaps of skin that create a striking resemblance with a piece of floating seaweed - a impression compounded by the fish's gently swaying motion when swimming. The species' generic name, Phycodurus, actually comes from the Greek word "phūkus", meaning "seaweed". Some leafy seadragons are even able to change their colour to match their surroundings.

The three fish mentioned as wrong answers also use various camouflage strategies to hide from predators (psychedelic frogfish) or to ambush their prey (tasselled scorpionfish and bulldog stargazer).

Answer: puff adder

The puff adder (Bitis arietans) is a large, highly venomous viper found in much of Africa. An ambush predator like many other snake species, it does not just rely on visual camouflage (as shown in the photo), but also on what scientists call "chemical crypsis", or scent camouflage. In the 2010s, a group of South African researchers conducted an experiment, using specially trained dogs and meerkats to determine whether these animals could detect puff adders by smell. They found out that neither group of animals was able to detect the snakes even when walking right past them.

This unique form of camouflage is essential for an ambush predator like the puff adder, which can spend weeks lying motionless in a single location waiting for their prey, and would otherwise be vulnerable to predation by other animals - as even their superb skill at visual camouflage can occasionally fail. It is quite likely that other ambush predators use a similar strategy to avoid detection during the long waits for prey to pass by. The mechanics of the puff adder's lack of smell are still unclear: it has been suggested that it might be related to the snake's very slow metabolism, or the unique structure of its scales, which would reduce the number of odour-producing bacteria and other microorganisms living on them.

Chemical crypsis has also been observed in a number of arthropods (both insects and arachnids) and a freshwater fish known as pirate perch.