Common Names: English: Great White Shark, White Shark, Blue Pointer, Afrikaans: Withaai, Witdoodshaai.
Scientific Name: Carcharodon carcharias
Size: Up to 6 m in length, weighing up to 2 tons.
Coloration: Dorsal surface (upper body) ranges from dark grey to light brown, while the ventral side (belly) is white.
Range/Distribution: White sharks occur in one of the widest habitat and geographic ranges of any fish. They are widely distributed around the South African coast (as well as the world’s oceans) with the highest concentrations occurring in temperate waters particularly in the vicinity of Cape fur seal colonies.
Reproduction: Males are believed to reach sexual maturity at 9 to 12 years of age when they are about 4 metres in length. Females reach maturity at a larger size of between 4 and 5 metres at 13 to 16 years old. Embryos mature inside the mother’s uterus, at first nourished by a yolk sac and later through unfertilized eggs. The gestation period is around 14-18 months and the female gives birth to live young estimated to be between 1 and 1,5 metres long.
Body Temperature: Its counter-current heat exchange system enables the great white to keep vital organs at up to 14°C warmer than the surrounding water.
Swimming Speed: It can reach close to 50 km per hour in short bursts, but in long distance, such as during ocean crossings, they move at a minimum sustained speed of up to 5 km per hour.
Teeth: 26 broad triangular shaped and serrated teeth in each row of the upper jaw and 24 more pointy teeth in the lower jaw rows.
Main Threats From Humans: Commercial long lining, poaching for jaws, teeth and fins, trawler and purse seiner by- catch, entanglement in and persecution from aquaculture facilities, boat traffic and pollution.
Shark Senses: Great whites became the ocean’s top hunters through the evolution of supremely-adapted senses and physiology.
Smell: Great white sharks’ most acute sense is smell. If there were just a single drop of blood floating in 10 billion drops of water, they could smell it! Their nostrils are on the underside of the snout and lead to an organ called the olfactory bulb. The great white’s olfactory bulb is reported to be the largest of any shark.
Hearing: Shark external ears are hard to see: they are just two small openings behind and above the eyes. The ears may be small, but they’re powerful. Inside, there are cells that can sense even the tiniest vibration in the surrounding water. Sharks also have an ‘ear stone’ that responds to gravity, giving the animal clues as to where it is in the water: head up, head down, right side up, or upside down.
Vision: A great white sharks has great vision. The retina of its eye is divided into two areas – one adapted for day vision, the other for low-light and night. To protect itself, the great white shark can roll its eye backward into the socket when threatened.
Electro – Reception: Sharks have a sense that humans can only be in awe of – they can sense an electrical field. A series of pores on the shark’s snout are filled with cells called the Ampullae of Lorenzini that can feel the power and direction of electrical currents. Scientists have discovered that sharks can use this sense to navigate through the open ocean by following an electrical ‘map’ of the magnetic fields that crisscross the Earth’s crust.
Taste: Great white sharks are opportunistic eaters. Depending on the season, area and age, they will hunt seals and sea lions, fish, squid, and even other sharks. They have taste buds inside their mouths and throats that enable them to identify the food before swallowing.
Touch: Great white sharks have an elaborate sense of touch through what’s called the lateral line – a line that extends along the middle of the shark’s body from its tail to its head. This line, which is found in all fish, is made of cells that can perceive vibrations in the water. Sharks can detect both the direction and amount of movement made by prey, even from as far as 820 feet (250 meters) away.