Colour plays an important role in the animal kingdom
Animals use colour for different purposes.
Small creatures often escape danger by advertising themselves as poisonous to predators: wasps and bees use the strong colour combination of yellow and black to warn birds not to eat them.
Likewise, the arrow poison frogs of South America and coral snakes announce their poisonous nature through their brilliant colours.
Some predators change their body colour to attract their prey.
The South American leaf fish, with a leaf-shaped body complete with stalk, can adapt its body colour to the changing colours of real leaves to attract, and then swallow, any small fish that approaches it.
Similarly, the colours of the mantid match those of tree branches and leaves so that it can prey on small insects.
In some other cases, colours are used for recognition. When many closely-related fish such as butterfly fish live together on a coral reef, they develop brilliant colours and marks to help them distinguish one species from the other.
Colour may also be used to in dicate territory. The African fish eagle displays bright white feathers on its head.
One theory is that the white head acts like a flag marking the exact site of a nest (when the bird is sitting) so that other eagles can avoid the nesting territory. If an intruder ignores the message, he will be driven off.
In West Africa, the male mandrill has a red-and-blue face which can warn others of his power and aggressiveness. Its appearance helps him establish his position in the group without a fight.
Showing off one's colours plays an important part in courtship.
Fighting between males to obtain females is one way of making sure that the fittest male will pass on his genes to the next generation. A safer way to win a female is by an alluring display.
Most of the male birds have more beautiful feathers in their breeding season.
The male peacock shows its tail open into a fan, then faces the female peacock and shakes his tail so that the feathers quiver. It also can send a message that it is healthy.
So, a sickly male's tail feathers are not bright and in a poor condition.
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