Imagine driving on a highway and the road is shimmered by the scorching midday sun. Whilst you drive further on a day like this, you might envision a wet patch gleaming on the road. Does it make you wonder how a mirage passes by playing with your vision?

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While there is physics involved in this phenomenon, evolution through natural selection has rendered some of its own biological members the ability to play with visual perceptions in subtle but enchanting ways!

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What comes to your mind when you hear the word camouflage?

 

Some might visualize a chameleon blending in almost any background possible. Others might envision a soldier wearing camouflage pants and shirts to match the earthy tones for their defence. Colourful frogs, butterflies, snakes and so on might cross your mind as you think deeper about this phenomenon. Nature is filled with some of the most fascinating examples of camouflage.

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Camouflage as a Prehistoric Phenomenon

 

The coloration patterns found on the Sinosauropteryx, a tiny, feathered, carnivorous dinosaur that lived in what is now China during the Early Cretaceous period was studied by a group of scientists. They discovered evidence of coloration patterns corresponding to modern animal camouflage by tracing the distribution of the dark pigmented feathers over the body. This included stripes running around its eyes and across the tail, and countershading with a dark back and pale bottom. By contrasting and comparing the mask and striped tail with the colours of contemporary animals, we can learn more about the evolution of camouflage as a means of natural selection [1]. 

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The presence of stripes on only tails rather than the whole body of certain animals is not well understood, but they are suspected to function as a type of disruptive camouflage. Disruptive camouflage means visually separating the outline of a portion of the body from the others and to make it less noticeable. It could also serve as a type of deception by attracting predators' attention to the tail and away from the more vital parts - the body and head. Birds are found to be the most evident illustration of this as they descend from the theropod dinosaur [1]. 

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Early tyrannosauroids, the ancestors of the ferocious T-rex, coexisted with Sinosauropteryx and may have even hunted the little dinosaur. Sinosauropteryx hunted tiny lizards, as was demonstrated by direct evidence in the shape of a whole animal preserved in the stomach of one of the specimens found. Hence, it is clear that camouflage patterns were developing at that time; since vision was critically important to these dinosaurs while they were hunting and being hunted. This example demonstrates camouflage as a prehistoric phenomenon and its evolution in the animal kingdom.

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Camouflage in Modern Day Animals

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Animals use camouflage primarily for defence. Blending in with their background prevents them from being seen easily by predators. The use of warning coloration, mimicry, countershading, background matching and disruptive coloration are mechanisms through which animals employ camouflage.

 

Sneaky Snakes!

The harmless scarlet king snake has stripes that resemble those of the deadly coral snake, but it is not poisonous. The only significant distinction between the two is the arrangement of the colours in their patterns. While the pattern for coral snakes is red-yellow-black, for scarlet king snakes it is red-black-yellow [2].

The difference is simple for anyone to remember thanks to a rhyme!

Red on yellow kills a fellow,

Red on black won’t hurt Jack!

This is a classic example of mimicry: a form of camouflage in which one organism imitates the appearance of another to avoid predators.

 

The Walking Leaf!

The leaf insect or the waking leaf belongs to the family Phylliidae and is quite like its name. The walking leaf's body has patterns on its outer edges that look like the bite marks that caterpillars leave behind in leaves. To resemble a leaf swinging more accurately in the breeze, the insect even sways while walking!

This is an example of a type of camouflage known as background matching- one of the most prevalent forms of camouflage. It is a mechanism through which a particular organism hides itself by resembling its surroundings in terms of its hues, shapes, or movement [2].

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Mottled Moth!

It is challenging for predators to determine the form and direction of the tiger moth as it is mottled with intricate patterns of black, white, and orange on its wings. This is an example of disruptive camouflage: when an animal has a patterned coloration, such as spots or stripes, it can be difficult to detect the animal's contour [2].

 

Lurking Leopards!

Black rosettes on a light tan backdrop serve as the hallmarks of the leopard’s well known coat patterns. Their coats also include a subtle countershading to help them amalgamate with their environment and evade detection by prey. A leopard's body has a significantly lighter underside than the rest of its coat, which consists mostly of its belly and the bottom of its legs. This produces a shading effect that helps conceal the leopard's body form and contour, making it more challenging to see in low light or when seen from below.

This is a typical example of countershading, which is a type of camouflage wherein the animal’s body is darker in colour, but its underside is lighter. It works by manipulating the interactions between light and shadows; thus, making the animal difficult to detect [2].

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But what allows these animals to change their colours?

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Animals can camouflage themselves through two primary mechanisms: 

1. Pigments - biochromes

2. Physical structures - prisms 

 

While some species have natural and microscopic pigments known as biochromes, others possess physical structures like prisms for camouflage. Biochromes can reflect some wavelengths of light while absorbing others. Species with biochromes can actually seem to alter their colour. Prisms can reflect and scatter light to give rise to a colour that is different from the animal’s skin [2].

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Camouflage is not quite restricted to the sense of vision. There are several other ways evolution has taught the living world to adapt and protect themselves in the wild. There is a whole exciting world of behavioural and olfactory camouflage employed by diverse species in the animal kingdom. 

 

Ultimately, the compelling association of camouflage with the phenomenon of mirage conveys to us how nature always evolves and expands to secure the continued existence of its inhabitants. From the glistening heat of mirages on arid vistas to the delicate patterns on the wings of a butterfly, this fascinating juxtaposition of mirage and camouflage delivers a peek into the incredible mechanisms that animals deploy to traverse their natural habitats and survive amidst the obstacles they encounter.