Great White Sharks have become a new addition to South Africa's Big Five in game-watching. Now you can get close to these fear-inspiring and fascinating creatures, with professional guides.
Gansbaai has become known as the Great White Shark capital of the world. Sharks will also be seen in False Bay. The video below shows a Great White feeding on seals off Dyer Island near Gansbaai.
Cage diving is, above all, an educational experience, dispelling many of the myths about these creatures. Sharks are attracted to the boat. Apart from sharks, these excursions usually come across a wide variety of other marine and bird life.
More on the Great White Shark... Carcharodon Carcharias
Extracted from SharkProject's Workbook – see www.sharkproject.com
White Sharks may already be biologically extinct, and our grandchildren may never see these animals in their natural habitat, only as images on their TV screens. With the number of sharks seen in Gansbaai, South Africa, it may seem that there are a large number of white sharks in our oceans but sadly, this is not the case. The number of white sharks in our oceans is decreasing rapidly, in fact the population densities of white sharks are so low, the successful reproduction to sustain a guaranteed stable population is more than questionable.
Many of the roughly 470 species of sharks are already overfished, while some of them, including white sharks, are threatened with extinction. Sharks are the most abundant predators above 50kg on this planet, and for good reason. Their numbers is needed to keep the oceans in balance. A reduction or even elimination of these animals will destroy every marine ecosystem, forever. And this would also be a threat to mankind.
English — White shark, great white shark
French — Grand requin blanc
Spanish — Jaquetón blanco
German — Grosser Weisser Hai, Weisshai
Lamnidae (Mackerel Sharks)
Five species belong to this family: Shortfin mako, Longfin mako, Salmon shark, White shark.
All of them have a conical snout, lateral keels (one or two) on the peduncle and homocercal tails (the tail's upper and lower lobe are of equal length).
|Length at birth||100 – 120 cm (100 cm = 1 metre = ±39 inches)|
|Maximum size||about 700 cm|
|Size at sexual maturity (female)||400 – 470 cm|
|Size at sexual maturity (male)||350 – 600 cm|
Black or dark grey on their top surfaces and white on their underside. The pectoral fins have black tips on the underside and a distinctive black axillary spot where they join the body.
White sharks are found in most oceans between 50° and 60° latitude in both hemispheres. They prefer cooler waters, close to shore but can also be found in greater depths exceeding 1000 m.
Sexual maturity, pregnancy
It takes females between 12 and 14 years to reach sexual maturity, males need 9 to 10 years. The fact the pregnant females are rarely found could indicate that they leave the others before giving birth. White sharks are aplacental viviparous, meaning they bear live young without connection to the mother (aplacental) during the pregnancy. To get enough nutrition while inside the mother, embryos feed on other eggs (oophagism). It is still not known how long and average pregnancy is but it may range between 12 and 14 months. The number of embryos carried during an average pregnancy may be between 2 and 14.
Not much is known about their migration patterns. Some experiments with satellite tags indicate that the males migrate and females prefer to stay close to one place. Some sharks can stay in the same area year after year.
Although white sharks have often been portrayed as "lonely hunters" they are social animals and can swim in groups of ten or more animals.
A few species of shark, including white sharks, are semi-warm-blooded with their blood temperature staying about 10 to 15 degrees Celsius above the surrounding water temperature. The prevention of heat loss is due to special arrangements of blood vessels (also known as wonder nets, or rete mirabile) found along their flanks, the eyes, brain and intestines. This higher body temperature allows the muscles to contract faster, hence increasing agility in cold water. So despite their size and weight, white sharks can accelerate quickly and reach high speeds. However, since they are semi-warm-blooded, they lack endurance compared to true warm-blooded marine animals.
White sharks and humans White sharks are often called the most dangerous shark. This statement is a result of the movie "Jaws" and the unfounded distribution of misinformation through the media. Compared to other shark species, white sharks are not at the top of the "biters". However due to their size and weight even an exploratory bite can be devastating. White sharks cause no more than one or two fatal incidents a year (around South Africa). Overall it is estimated that 10 to 12 accidents occur with them on a worldwide basis during a year. Humans do not belong to the prey spectrum of white sharks, or any shark for that matter. Bites occur for different reasons: exploration, play, target practice, reproduction-induced competition... but not hunger related.
New research has shown that mistaken identity is a myth. Surfers are not bitten because they may look like seals from below. White sharks know they are not seals but they don't understand what this structure at the surface could be, and then on rare occasions try to find out.
White sharks do not deliberately cause humans harm. On the other hand, humans do: the current number of slaughtered sharks per year reaches about 200 million.