The great white shark has a wide-ranging diet and preys upon a variety of fish and marine mammals. Fish such as salmon, hake, halibut, mackerel and tunas are common prey, as are marine mammals such as porpoises, sea lions, small whales and seals. However, great whites also eat other sharks, sea turtles and seabirds, they also feed upon blubber from dead whale carcasses.

The great white is at the top of the list of man-eaters and is responsible for about 5-10 shark attacks a year. It is thought that great white shark attacks may be due to mistaken identity, as the silhouette of a swimmer viewed from below is similar to a seal or sea lion. Other theories are that attacks are caused by territorial aggression and competitive displacement, as almost all shark attacks on humans appear to be non-predatory in motivation. By looking at the manner in which great white sharks attack their preferred prey i.e. seals, sea lions, etc. it is possible to identify the possible reason for sharks biting human surfers... Shark diving, or shark cage diving, allows divers, researchers and film crews to view the extraordinary world of great white sharks in comfort and safety. Specially designed shark viewing cages allow divers total freedom of movement and 360 degree shark viewing.

Scuba diving packages can be organised through our online travel agency in Australia to wiew the great white off the South Australian Coast around the scenic islands of North and South Neptune and Dangerous Reef near Point Lincoln, as these are natural feeding grounds for the great white.

Typically, a great white stalks its prey from a position well under the surface - where, from above, its black back is almost invisible against the dark substrate and then the great white attacks in a sudden vertical rush, often leaping from the water in a spectacular explosion of spray and blood. The shark has obviously seen the seal silhouette from deep down, and when the time is right, launches into an upward attack. When viewed from underwater on a seal decoy that is stationary, the great white 90% of the time breaks off from a full vertical attack in the last few metres before contact. observations from seal colonies indicate great white sharks hunting large mammals often lunge and bite at prey, release it and then retreat briefly.Because seals have sharp teeth and claws capable of inflicting serious injury, this method of attack might be sensibly cautious hunting. it appears a great white shark hangs back and waits until the seal dies before going in to eat it.

This could explain shark attack patterns against humans which may take the form of a quick bite and release. This is almost certainly what happens in most cases with surfers or divers on the surface, as 77% of great white shark attacks are non-fatal and would appear to be cases of mistaken identity.

One must bear in mind however the size of the great white and the resultant injury even from an investigatory bite may be serious and in some cases fatal. If great white sharks were really interested in humans, upwards of 90% of attacks would be fatal and there certainly would be a lot more great white shark attacks.

Great white sharks appear to have at least 40 different behavioural mannerisms almost all of them difficult to interpret and give meaning to. Here are a few of the more common ones:

• Repetitive aerial surface gapes. an adult great white shark rolls onto its side or back and then swims awkwardly along the surface while slowly and rhythmically opening and shutting its mouth, this could be a frustration response which occurs when feeding attempts are repeatedly thwarted and this action works to release pent-up aggression.

• Breaching. Often great white sharks are observed breaching for no apparent reason. It may be a form of communication as such a splash carries a great distance underwater, or it may be to rid itself of external copepods (parasites).it may even be a territorial response. Towing an imitation seal behind a boat to encourage a great white to leap out from the water in a dramatic breach is condemned by serious shark researchers and banned in Australian waters.

• Predation induced dazed seal syndrome (PIDSS). this is when a great white shark chases a seal often without contact and the seal appears to become so panicked that it goes almost into a transitory state and flounders at the surface for often up to two minutes.Once the effect of the dazing is over the seal quickly (if it is still alive) returns back to the island

• Weather induced activity. after a frontal system has passed and large seas wash the islands harbouring seal colonies, shark activity is at its peak and sharks display more active mannerisms. the following reasons could contribute to this activity
• Dead or injured seals being washed off the island
• Decreased water clarity, masking the great white hunting in the turbid water.

• Early morning feeding. the most active hunting period for the great white is in the morning. this is probably a response to seals leaving the islands, and with the sun being at its most critical angle, the seals, at that time of day having little vision of what's beneath them. Great white sharks are biologically more suited to daytime feeding and the morning may be the first hunting chance they have in a day.

• A berley 'high'. tossing a pungent mix of fish flesh and oil into the water is the best way to encourage large ocean-going sharks to the surface and around boats where they can be observed. But this can stimulate a narrow range of extreme reactions, a kind of berley 'high' in which they sometimes thrash around and gnash away at anything they can.That, unfortunately, is the state in which most people see white sharks. Note: The use of berley or the practice of chumming for great whites, in Australian waters is permitted provided the berley is a fish product. The theory that chumming encourages sharks to look for an easy feed around boats remains a contentious issue.

Range & habitat of the great white shark

Information suggests great white sharks can cruise hundreds of kilometres between feeding spots and sometimes to considerable depths.The white shark inhabits the coastal and offshore waters of the continental shelf. Periodically it will wander into bays and harbours. This shark also inhabits waters around oceanic islands.

Great white sharks live in all coastal temperate waters, and have been known to occasionally make dives into the deep water of open oceans. They can be found in water as shallow as three feet deep, and as deep as 1280 metres.Great whites are found on the following coastlines:

• California to Alaska
• East coast of the USA
• Most of the Gulf coast
• Hawaii
• Most of South America
• South Africa
• Australia (except the north coast)
• New Zealand
• Mediterranean Sea
• West Africa to Scandinavia
• Japan
• Eastern coastline of China to Russia

A theory has been put forward, referred to as the 'cafe-highway hypothesis' to help explain the long-distance travels of the great white shark. It has been suggested the great white moves, perhaps even migrates, along certain predictable routes - 'underwater highways' - often stopping at, and retuning to, the same 'cafes' along the way to feed. If these 'highways' and 'cafes' can be identified then scientists should be able to advise people how best to avoid unwanted encounters with the great white.

• Known depth range is from the surface to at least 1,875 m (6,150 ft)
• Seems to prefer waters with sea surface temperatures of 15-22°C (59-72°F)
• Known sea surface temperature range is 7-27°C (45-81°F); probable bottom temperature at maximum recorded depth is 4°C (39°F)

The great white shark is among the most widely distributed of sharks (rivalled only by the 'bluntnose six gill'), owing - in part - to its ability to maintain its body temperature up to 15°C (27°F) warmer than the surrounding seawater. This capability for 'warm-bloodedness' is one of the reasons why great white sharks remain such active and alert predators in a wide range of water temperatures. The long gestation period, late age of reproductive maturity and relatively small litter size combine to give white sharks a naturally low reproductive rate. For this reason, great white sharks became protected is South African waters in 1991. Since then, that protection has been extended to several other areas they're known to frequent. There are no estimates of the world's total white shark population or of the number in Australian waters. And it's impossible to say with scientific certainty whether the species is in decline although there is much anecdotal information to suggest it is.