THE GREAT
WHITE SHARK
Gday folks,
Welcome to some detailed facts about the greatest fear for surfers in Australian waters. The great white shark, commonly known as the great white or
the white shark, is a species of large mackerel shark which can be found in the
coastal surface waters of all the major oceans.
The Great White Shark is a large species
of shark found mainly found inhabiting the temperate and tropical coastal
waters worldwide. They are the largest predatory fish
species
in the world known to grow to lengths of 8 meters or more and weighing over 2
tonnes. Great White Sharks are hugely powerful predators
that have developed a fearsome reputation as being one of the most prolific
"man-eaters" on the planet, with up to half of annual shark attacks
on humans
being reportedly caused by them. Also known as White Sharks and White Pointer
Sharks, Great White Sharks have been one of the most ruthless ocean
predatory fishes for nearly 20 million years, but despite their high profile
reputation, they are actually a lot less common compared to other widely
distributed shark species.
Although surprisingly little is still known about their biology and population sizes,
it is widely agreed within the scientific community that Great White Shark
population numbers are decreasing worldwide as they are threatened
by both hunting and habitat
loss throughout much of their natural range.
Great White Shark Anatomy and
Appearance
Like almost all shark species, Great White Sharks have a highly distinctive appearance with large, torpedo-shaped bodies and a pointed snout. They have very tough skin that is covered in tiny teeth called denticles that is slate-grey to black in colour on the top of their bodies which helps them to remain camouflaged into the rocky, coastal sea floors where they are most commonly found. The underside of the Great White Shark is white and is what has led to their name. Great White Sharks have powerful, crescent-shaped tail fins that help to propel them through the water at a tremendous speed, and are aided by their pectoral (side) fins that are held out in fixed wings to prevent the Great White Shark from sinking. The large and highly characteristic dorsal (back) fin of the Great White Shark is used to help them to steer through the water, along with diving and helping them to balance. One of the most characteristic features of the Great White Shark is their jaw. Their mouths are filled with up to 300 serrated, triangular teeth that are arranged in rows and are replaced continuously throughout their lives. Each tooth can grow to around 6cm in length providing Great White Sharks with a formidable bite when they are attacking their prey.
Great White Shark Distribution and Habitat
Great White Sharks are widely distributed around the world, but are most commonly found in temperate and tropical coastal regions but also in cooler waters and open ocean too. Despite this, they are most commonly seen in South Africa (where there are the biggest population numbers), Australia, California and the northeast of the United States but are also known to range into cooler regions and visit tropical islands including Hawaii and the Seychelles in areas within a greater expanse of open water. Great White Sharks are found swimming either below the surface or just off the ocean floor depending on the region and their feeding habits. Their coastal dwelling nature is largely attributed to their prey species but they are also known to travel vast distances through the ocean from South Africa to Australia and from the Californian coast to Hawaii in the deep Pacific.
Great White Sharks are largely solitary animals that only tend to come together to mate but have been seen in pairs or small groups around large carcasses. They are highly adaptable and powerful predators that rely less on their eyesight and more on other senses in order to detect their prey. When in the open oceans Great White Sharks must swim constantly or they will simply drown. During swimming, sea water is forced into their mouths and over their gills where oxygen is then taken in. Great White Sharks swim in an "s" shape in order to move through the water more efficiently. By flexing their body and moving their incredibly strong tail fins from side to side they are able to travel vast distances. Powerful and more sudden movements of their tail fins enable Great White Sharks to make high-speed dashes when chasing fast moving prey and have even been commonly seen leaping out (breaching) of the water in a similar way to whales when they are attacking their prey from underneath.
Great White Shark Reproduction
and Life Cycles
Like many other shark species, female Great White Sharks give birth to live young rather than laying eggs. The female Great White Sharks (which are bigger than the males) are thought to reach reproductive age at around the age of 17. After an estimated incubation period of between 12 and 18 months, the female gives birth to between 4 and 14 pups that are roughly 1.2 meters long (or more) at birth. Great White Shark young hatch inside the uterus and are thought to gain their nourishment from eating unfertilised eggs and other embryos until they have developed enough to be born. Female Great White Sharks are thought to have new litters every 2 or 3 years, normally in warm coastal regions where the young have safe nursery grounds in which to grow. However, many of these areas are being threatened by habitat degradation and human interferences to keep Great White Sharks away from regions where people commonly surf and swim.
Great White Sharks are fearsome carnivores that primarily hunt large marine mammals in order to gain their nutrition. Seals, sea lions, porpoises, dolphins and smaller whales are among their most commonly hunted prey species around the world. Great White Sharks have poor eyesight in comparison to their other senses and use both their sense of smell and ability to detect vibrations caused by animals in the water to detect their prey. Once located, Great White Sharks fiercely attack with great speed and force before retreating and leaving their wounded prey to weaken before returning to feed once it is safe to do so. Although they are largely solitary, Great White Sharks can be seen in pairs or small groups to feed on a large whale carcass. In these circumstances, larger and more dominant individuals feed first with varying swimming display patterns thought to contribute to establishing their dominance hierarchy.
Great White Shark Predators
and Threats
The Great White Shark is the largest predatory fish in the ocean and one of the most formidable aquatic hunters in the world and so naturally, very few animals would prey upon fully grown Great White Sharks. The smaller and more vulnerable juveniles however, are more threatened by large ocean predators including Killer Whales and other shark species. The biggest threats to global populations of Great White Sharks are those caused by people. Great Whites are hunted for their jaws, teeth and fins by fishermen and trophy hunters and are also sometimes accidentally caught in nets fishing for other species such as Tuna. Beaches that has been meshed to protect swimmers from shark attacks and habitat degradation throughout their natural range has also contributed to the global decline in their population numbers.
Great White Shark Interesting Facts and Features
Great White Sharks have an exceptional sense of smell which they use to detect prey. Amazingly they are known to be able to sniff out blood in the water from half a kilometre away. Along with other shark species, Great White Sharks have special organs known as lateral lines (rib-like lines on the sides of their body) which are able to detect the tiny electromagnetic field generated by other animals in the water, which they use to find prey. Hunting larger prey species means that feeding for Great White Sharks can be done more efficiently than if they fed on smaller fish and birds. Great White Sharks are thought to consume an average of 11 tonnes of food every year and after a particularly big feast, may not feed properly again for up to 3 months. In some situations, Great White Sharks have been known to swim along baring their teeth, which is thought to both serve to warn off competitors for food and rival sharks that may be intruding on their personal space.
Great White Shark Relationship with Humans
Humans have a long established negative relationship with Great White Sharks all around the world, as they are responsible for the majority of all shark attacks on people. Despite the fact that such attacks are widely documented in the news, fatalities from Great White Shark attacks are thought to be less common than those caused by lightning strikes or bee stings. Due to the way in which Great White Sharks hunt (known as sample biting where they first attack their prey to wound it before later returning to eat), it is widely believed that people are not considered to be a desirable meal for them as such instances of return are incredibly rare. The high profile nature of these attacks though has led to Great White Sharks developing a reputation of being fierce man-hunters when in actual fact, they have simply mistaken a person swimming or surfing for a seal on the surface of the water. Great White Sharks have also been known to bite or repeatedly bash small boats with their snouts and can cause enough damage to make them to sink.
Great White Shark Conservation Status and Life Today
Although little is known about the exact global population numbers of Great White Sharks, particularly in regions where they are less common, their numbers are thought to have been declining rapidly over recent years. Great White Sharks are now listed by the IUCN as an animal that is Vulnerable in their native environments and they are more also more heavily protected in certain areas. Hunting, habitat degradation and campaigns to kill Great White Sharks after there has been a high profile attack documented in the media have all led to their population declines, along with the capture of them to be exhibited in aquariums around the world.
Clancy's comment: Ferocious when angry or hungry. But, don't forget that not all sharks live in the sea. Some have two legs and walk the earth.
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