The water foams, we hear the heart-stopping sound of a human body being ripped apart and the screams of the girl before she disappears amid gurgling noises into the depths. Jaws, which first appeared on the world's cinema screens 16 years ago, did nothing to popularise the shark. The image it created persists, of an insatiable beast of prey cruising the beaches of the globe night and day in search of human flesh. And it promoted an industry that makes millions from products processed from sharks. The chance of being hit by lightning is one in 2 million, of dying from a hornet sting one in 5m, of being struck by a falling piece of aircraft one in 10m.
Sharks never attack without reason.
So the threat of being attacked exists only for injured humans or animals thrashing in the water, for underwater hunters carrying their prey or for paddling surfers, who strongly resemble a favourite shark meal - seals. The five factors are likely to occur at once only in the event of a shipwreck or air crash. A shark can pick up soundwaves over 5km and home in on the source to within a square metre, even in zero visibility. It can smell blood in the water at 8km, detect increased electrical current in the bodies of wounded fish or panicking humans, even hear their heartbeats. It can move at 60kmph-plus.