Great White Shark video Australian outback adventures White Pointer mackerel shark

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Great White Shark

Great White Shark in the wild

Latin name: Carcharodon carcharias

Family: Lamnidae

Description: The Great White Shark or “White Pointer” is a huge mackerel (lamnidae) shark which inhabits the coastal surface waters in all the major oceans. It can grow as long as 6 metres or 20ft and can weigh up to 2,250 kilorams or 5,000lbs. In its genus Carcharodon it is the only known surviving species.

Females are generally larger. It is a pelagic fish and is considered an open-ocean dweller and has been found at depths of 1,280 metres or 4,200ft but is most commonly found close to the surface.

They are streamlined swimmers, and have a torpedo-shaped body and a pointed snout.

Great whites have approximately 3000 teeth which are arranged into rows. The first two rows of teeth serve to grab and cut prey, while the teeth in the last rows rotate into place when front teeth are broken, worn down, or fall out. The teeth are triangularly shaped with serrations on the edges.

The shark is a dull grey colour on the back and white underneath. They have three main fins: the dorsal on its back and two pectoral fins on its side. It has a crescent shaped tail with five gill slits on Great White Sharks

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Family groups: Great White sharks have been shown in South Africa to have a social structure involving a pecking order with females dominating over males, bigger sharks over smaller sharks and sharks will dominate in their own territory over other sharks entering it they are not necessarily aggressive to each other unless they have invaded another’s space.

Great Whites are ovoviviparous, meaning they develop their eggs in the uterus where they hatch and continue to grow until birth in Spring and Summer when they have become capable predators. The mother shark has to fast herself to prevent herself from eating her young.

Distribution Map:
Distribution map of Great White Sharks

Distribution: Great Whites generally reside in offshore coastal areas with water temperatures of 12 – 24 degrees C (54 degrees to 75 degrees F).

Most Great whites inhabit the waters off the southern Coast of Australia, California, Central Mediterranean, South Africa, Mexico’s Isla Guadalupe and in the Tropical waters of the Caribbean and Mauritius.

There are significant number of Great Whites found around Dyer Island in South Africa where they are undergoing research.

Great Whites are known to travel huge distances; for example they have been known to migrate from South Africa to the northwestern coast of Australia, a distance of 20,000 kms in less than 9 months.

Feeding: Great white sharks are carnivorous and favour eating fish, rays, dolphins, porpoises and whale carcasses. They also eat earless seals, fur seals, sea lions, sea otters and turtles. They prefer prey with high contents of fat for energy. They are also known to eat indigestable objects – anything from rubber tyres to scrap metal.

Great whites use their extra senses being that of. electrosense and mechanosense which help them to find their prey from a long distance. Smell and hearing are then used to confirm the target is food. The shark will then use sight at close range for the attack.

Research shows that sharks generally hunt in the first 2 hours after sunrise as it is more difficult for them to be seen at the bottom. It is then that they have a 55% chance of success and it decreases to 40% in late morning and after this they cease hunting. They ambush their prey from below.

Their techniques for hunting can change depending on their prey. For example a Great White will attack a Cape fur seal by ambushing it from below and then hurtling towards it at great speed hitting it in the middle section of its body. The great speed actually results in them breaching out of the water. They will also chase their prey if they have missed them and will attack on the surface. Another technique is immobilizing the northern elephant seals by taking a large bite into their hindquarters and allowing the seal to bleed to death.

Interesting facts: Like all sharks Great whites have an extra sense called the Ampullae of Lorenzini allowing them to detect the electromagnetic field which enables them to be able to sense the movement of other animals. The movement of any living creature creates an electrical field that can detect s billionth of a volt.

Every time a living creature moves it creates an electrical field and because of the extra sense a Great White can detect half a billionth volt. To make a comparison it is the same as detecting a flashflight battery from a distance of 1,600km away.

The Great White is able to maintain its body temperature as warmer than the surrounding water this is called “rete mirabile” this makes them poikilothermic. This allows sharks to hunt for fast moving sea lions. The web-like structure of veins and arteries are situated down the lateral side of the shark - this warms the cooler arterial blood with the venous blood allowing the shark to conserve heat.

The Great White shark reaches maturity at the age of 9. They grow approximately 25-30 cm per year. The females will have a litter of about 7-9 pups and she will only reproduce twice in her whole life.

The great white shark is one of only a few sharks known to regularly lift its head above the sea surface to gaze at other objects such as prey; this is known “sky hopping”.

Endangered: Excessive and unregulated trade has resulted in the decimation of Great Whites. The U.N. affiliated Convention on International Trade in Endangered Species is asking for increased protection of the sharks, whose teeth and jaws can fetch tens of thousands of dollars. Now trade will be closely monitored, and hopefully banned completely if great white numbers keep falling.

The general picture is that overall there is a long-term decline in the abundance of Great White Sharks in Australian waters. Globally, in the last 50 years there has been a reported decline of between 60-95% in Great White Shark numbers.

Great White Sharks in Australian waters face threat from commercial and recreational fisheries, trade, tag and release practices, shark control activities.

Myth: The most common myth is that because of poor vision, Great Whites attack divers and surfers in wet suits, mistaking them for seals and sea lions, their main prey. Great whites in fact are sharp sighted seeing in colour and do not mistake humans for prey but are however curious. Hence the reason they slowly approach humans and take a bite as opposed to the way in which they attack seals and seal lions. They now believe that sharks see as well below the surface as humans do above. They use their teeth to detect what an object is.

Humans are not healthy eating for great white sharks because the sharks’ digestion is too slow to cope with the human body’s high ratio of bone to muscle and fat. It is for this reason that in most recorded incidences, great whites break off contact after the first bite. Fatalities are normally caused by loss of blood from the initial injury instead of from critical organ loss or from whole consumption.