Most people believe that only humans work with colour. In fact, humans have poor three-dimensional colour vision. They can’t see many of the colours that animals with four and five dimensional colour vision can. Butterflies see the maximum colours, while most birds can see ultraviolet as well. But every living being from plants to the tiniest insect uses colour in glorious ways.

Every coloured feather, each pigmented hair or scale has a function. The colour of the markings on the peacock’s tail, for instance, proclaims his worthiness as a mate.  Clear and bright markings indicate him to be strong and healthy which is what  peahens desire.

Male North American barn swallows use their breast colours to convey status, health and the ability to successfully raise young. Males with darker breast colours mate earlier; have more young and their wives cheat on them less! In a study by the University of Colorado,  painting their breasts immediately won them all this, when the colour washed off next season, they were back to fewer females!

The male cardinal’s bright red plumage advertises his skill at finding foods rich in carotenoids (which lend him that colour) indicating his ability to feed a family. The female cardinal with tan feathers with only a tinge of orange, is distinctly less colourful, the reason being that she sits on her nest for three weeks and bright feathers would only attract predators.

Many species of birds have some form of red on their tails. The smaller the bird the more this is hidden from potential predators and displayed only during courting. One family of small Pionus parrots from South America is discreetly coloured all over but their vent areas are bright red or pink. In his courting dance, the male briefly displays his vent to his prospective partner. Similarly spiders rear up to show their most conspicuously coloured parts to females they fancy.

Colour is an integral part of the bower bird’s love life. Males build bowers, paint them with plant pigments and decorate them with colourful objects to attract females.

In 1876 Charles Darwin wrote that most primates were attracted by colour. Rhesus Macaque females prefer their men with red faces! The colour red signifies high levels of testosterone which in many male animals means a healthy immune system and good genes. Our use of cosmetics is probably the instinctive  behaviour of  ‘sexual selection’.

Dragon lizards choose a mate based on head colour. Redheaded male dragons are better fighters but not necessarily better lovers than yellow heads. The females mate with a multitude of males to increase their chances of top quality sperm but they deliberately choose males with different coloured heads to avoid repeating the same partner.

The size of the coloured badges on the throats of tree lizards signals fighting ability and status. Most males have orange, yellow, or bi-coloured combination backgrounds surrounding a blue spot. The size of this blue spot signals status - the larger the spot, the more important the male.

Chameleons change hues to communicate. They render themselves temporarily noticeable to mates and rivals, remaining inconspicuous the rest of the time. In duels, each species has a distinctive set of dominant colours as well as a separate set of submissive colours used in defeat or rejection.

Fighting is costly. Therefore, it is to an animal’s advantage to assess the abilities of its opponent and compete more strongly against weaker competitors and avoid contests with stronger competitors. However, assessment may also be difficult or costly, making it sometimes advantageous for the animal to avoid direct assessment. This study examines male–male contests over access to fe-males in the spider Argyrodes antipodiana. Pairs of naive males in their first contest were more likely to escalate that contest if the pair consisted of large males. Thus large males were inherently more likely to escalate contests than small males. Second, males that had had experience at winning contests were more likely to win subsequent contests against spiders of the same size who had had experience at losing contests. These trained spiders responded differently from the onset of the contest suggesting that their experience had altered their perception of their chance of winning the current contest. These two results suggest means by which direct assessment may be reduced, and yet observed interactions could still follow predictions from game theory models. Mechanisms by which experience may reduce assessment are discussed.

In the ocean, squids change colours to blend into the environment or attract mates. This is done through controlling pigment-containing, light-reflecting cells on the outer layer of their skin which expand and contract to show or hide colours. Squids use colour to court females as well as fend off competing males. So on one side of its body, the animal produces a pattern that attracts females and on the other a pattern that repels males. Fighting between males is mainly communicated through colour with very little physical contact. Squids show chromatic displays with increasing intensity until one backs down.

In some insect species, colour helps regulate body temperature. Stick insects  range from light beige to mahogany. They expose or conceal pigment granules in their skin cells, making their colour lighter or darker. In the sun they remain pale, reflecting heat. As the temperature drops at night, they become darker to absorb heat. 

The most functional use of colours by animals is for camouflage either to hide from an enemy or to sneak up on their prey. The seahorse attaches itself to underwater plants, changing colour to match its environment. The octopus and the cuttlefish can change rapidly from colours that blend into the environment  to bold contrasting colours such as white and black. Some turn bright red to signify pleasure or warn others to stay away.

If you place a sole in an aquarium with light yellow sand; it will turn just that colour. Take this same sole from the aquarium and put him on a white porcelain plate, the fish turns almost white. During a study, one sole was found out of sync with the bottom over which he lived. His colour would be light when placed on dark, and dark when placed on light. It was found that the animal was blind! All experiments show that fish harmonisation is guided entirely by eyesight – which means intelligence of a high order.

The pupae of the tortoise shell butterfly can vary from black to white or metallic gold depending on the coloured surfaces on which they are suspended. In some cases even the cocoons spun by the larvæ are modified by the surrounding colours.

Some use warning colours to inform predators that they are unpalatable or poisonous. The most common warning colours are red, black and yellow. Coral snakes with their red, yellow and black rings proclaim their venom.  Some animals are born with bright colours. Others adopt colours to suit the situation. Poisonous milkweed beetles and ladybirds are both red and black. An insect predator learns to avoid all red-and-black insects. Non-poisonous insects mimic these colour patterns. The non-poisonous viceroy butterfly mimics the poisonous monarch butterfly. The bright stripes of the Heliconid family tell birds that they taste acrid. But tasty butterfly species mimic the Heliconid’s colours, tricking predators into leaving them alone.

Some insects use body colour to defend themselves in other cunning ways. The underside of the wings of the dull, blue-grey cream owl butterfly is mottled to look like feathers and has two large yellow-and-black "eyes" on the hind wing, which it displays when disturbed so that predators fly away in fright.

Some animals use colour to divert attention from their vital parts and instead attract an enemy to a portion of their bodies which can be detached allowing for escape. A snail has a bright red spot on the end of its tail. If a bird seizes this it will drop off allowing the snail to fall and save its life.

Some spiders with brightly coloured neon like stripes on their bodies use colour to lure their lunch by appearing like flowers. These hard crusted spiders have spines on either side to deter predators but insects that land on them are eaten.

Some species change colour depending on their situation. Single grasshoppers develop a dull coloration that help it hide. However, grasshoppers that grow up in a large group become an aggressive bright yellow and black!  

Some animals change colour seasonally along with the weather. In the summer the arctic fox has a dark coat in harmony with the rocky arctic regions. In winter when the snow falls, the animal becomes white. The lemming is dark brown to match the rocks on which it lives. But when the temperature starts falling it takes less than a week to turn its fur white by forcing air bubbles through the shafts of the hair, breaking up the light. Later a growth of white hair gradually replaces the hair that had been so suddenly changed. The arctic hare, stoat and weasel also change colour.  Amazingly while the stoat’s flanks and rump change to white at 36 degrees, its head and back change when the temperature touches 30 degrees.

Throughout the animal kingdom, rival males fight over mating rights.  When an African cichlid fish has defeated a rival and risen in ranking, within minutes there is a dramatic changes in his colouring. His body goes from being dull grey to flashy blue or yellow, and a black stripe appears across his face. This signals that he’s now the top fish and will defend his newly acquired breeding grounds. The loser immediately loses his colouring, black eye bar and his ranking.

Can you do any of this? Marvel at  these miracles of nature rather than destroy them so casually as food or pests or beasts of burden.