Eyebrows form a crucial factor in our facial appearance. This can be clearly proven, for instance, if someone you know decides to pluck their eyebrows - the slightest and subtlest of plucking will result in a change dramatic enough for you to notice.

In fact, a helluva lot of people spend quite some time preening their eyebrows - what was previously a vain measure taken only by women is now one commonly employed by the less-gentle sex too. They are a feature, which like the nose and ears, can be considered attractive or unattractive. In addition, they are defintely the most expressive feature in the face. Few seem to notice this - ask any random person what the most expressive feature in the face is, and you will be faced with replies like 'the eyes' and 'the lips'. This is true of course, but think about it. A simple raising or lowering of the eyebrows can show an affirmation, thought, incredulity, anger - much of the expressiveness attirbuted to the eyes in fact is partly due to the eyebrows. All this gives the eyebrows great facial importance in modern culture.

But what was the original function of the eyebrows? Evolution resulted in the loss of much of superficial hair in humans... yet the little lines of hair over each eye were retained. This means they must have had some vital function.

Anthropologists and scientists are as yet unsure about the actual function of the eyebrows, but the best guess is that they keep sweat and rain out of our eyes. The arch shape they sport diverts moisture down the sides of the face as opposed to in the eyes. This must have aided early man - being able to see in rainy conditions meant finding shelter was less difficult- also being able to see while sweating made chasing prey for food and running away from predators far easier.

Perhaps in modern day life, considering eyebrows as a survival tool is not that hip. This is what drives us to pluck them, shave them and pencil them in mercilessly. It is easy to forget their original role. But next time you are being hunted in prehistoric earth by some sabre-toothed thingie or other, try shaving off your eyebrows. You can bet your best club that having sweat pour into your eyes won't be helping you at all.