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Diving with Great White Sharks
During HMS Endurance’s visit to South Africa, POAC Andy Johnstone achieved a personal dream of diving with Great White Sharks. The great white shark is the best known type of shark. It is usually known as the “white death” because of its reputation as a man-eater.
“What we are dealing with here is a perfect engine, an eating machine. It’s really a miracle of evolution. All this machine does is swim and eat and make little sharks and that’s all”
From `Jaws’, 1975.
Accompanying Andy’s photographs, are some quick facts about sharks and in particular, the Carcharodon carcharias, the Great White Shark. After reading the information, see if you can decide if this monster is as bad as its reputation or is there another side to this amazing creature?
A shark is a type of fish and there are about 400 different kinds, or species of sharks. Sharks have the reputation of being huge, fierce killers. But fewer than a fifth of them are bigger than humans. On average, a shark is only about 60 – 90 cm long (2 -3ft).
The Great White is the fiercest, biggest hunting shark. It feeds on almost any prey, from whales to small fish – and even people. Great whites live in warm seas and ocean around the world and are rare as so many have been killed by people.
Sharks have excellent eyesight. In deep, dark water, they use a reflective layer at the back of their eyes to help them see. This acts a little like a mirror and makes better use of the dim light that enters their eyes.
The great white shark attacks its prey by biting it just once. It then moves off a short distance to wait for the victim to weaken or die, before returning to eat it. It does this to avoid injury in a struggle.
Nobody is sure how sharks find their way through the world’s oceans. The earth has an invisible magnetic field around it. Extremely hot metals deep inside the earth help produce it. As a shark swims, it may be able to detect changes in the field, which help it to find its way.
Between 5 and 10 people worldwide are killed by sharks each year. Every year, as many as 100 million sharks are killed as people kill them for food, sport or sometimes by mistake. Soup made from shark fins is a popular dish in some parts of the world. Sometimes when fishermen cruelly cut off their fins, sharks are thrown back into the sea. Without their fins, sharks cannot swim and so they eventually die.
Sharks almost never get cancer. Scientific research exploring the reasons for this may one day help to provide a cure for this serious disease.
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