With over 500 species each shark is a master in its own niche. Sharks have been around for more than 400 million years maintaining balance in the world’s oceans. 400 million years, think about that length of time……..
Sharks were around before, and have long since outlived dinosaurs, various mass extinctions, and global ice ages. The irony however is that in just 30 year, a nano second when compared to 400 million years, we as modern day humans have pushed many species to the brink of extinction.
We have learnt that smaller species of sharks form the bulk of the Great whites prey and that for less than half of the year they feed to any extent on seals. When the great whites are not around the seal colonies which are during the spring, summer and early autumn months, they are inshore over reef and sandy areas where they are most likely to find these smaller shark species. We have learnt that certain individuals return with others of their kind each year and clearly there is either a family or social bond between them of some description. Individual sharks have preferred hunting areas around the island and bigger sharks seem to prefer to hunt a little bit away from the island, thereby avoiding competition, not surprisingly the success rate of these larger sharks is slightly higher than the smaller ones slugging it out closer to the island.
So what makes sharks so successful and what can we do to make sure that these vitally important predators are around in the future?
The Great White has fascinated humans for centuries. Dive right in with Apex as we explore some of the most interesting Great White Sharks facts.
The Great white shark (Carcharodon carcharias), also known as the Great white, white shark or “white pointer”, is a species of the large mackerel shark which can be generally found in the temperate waters of all the major oceans. Great Whites get their name because they are great in size and have a clean white belly and underside. The upper body is slate-grey to blend in with the sea floor. It is a worthy name for a majestic and truly awesome predator. White Pointers were so named by Australian whalers as these sharks were often seen feeding belly up as they gorged on the blubber of whale carcasses. The normally, rarely seen white underbelly was in this case so prominent that it inspired the name “White Pointer”. Great Whites are streamlined, torpedo-shaped fish with powerful equally lobed shaped tails that can propel them through the water at speeds of up to 25 miles per hour. Aside from giving thrust, the caudal keel(tail) acts as a stabilizer.
The Great white shark was one of the many species originally described by Linnaeus in the landmark 1758 10th edition of his Systema Naturae, its first scientific name, Squalus carcharias. Later, Sir Andrew Smith gave it Carcharodon as its generic name in 1833, and also in 1873.
Found in cool, coastal temperate waters throughout the world, there is no reliable data on the Great white’s population. But estimates suggest that populations in South Africa which up until recently was thought to be the species’ highest aggregation area may number less than 500. However, scientists agree that their numbers are decreasing precipitously due to overfishing of their primary prey species, accidental catching in gill nets and other fisheries, as well as climate change among other factors. They are classed a vulnerable species under CITES. According to the Guardian (2010), a recent survey completed as a part of the Census for Marine Life, has found that there are only some 3,500 individual Great Whites left in the wild–around the same number of tigers that conservationists believe are left.
The Great White Sharks body is equipped with five gill slits, no fin spines, an anal fin and three main fins. The dorsal fin is located on top of its back and two pectoral fins are located on its sides.
While these measurements have not been confirmed, some Great white sharks caught in modern times have been estimated to be more than 7m (23ft) long, but these claims have received some criticism. However, J.E. Randall believed that Great white shark may have exceeded 6.1m (20ft) in length. A Great white shark was captured in Australia on 1 April 1987. This shark was estimated to be more than 6.9m (23ft) long by Peter Resiley and has been designated as KANGA.[Another Great white shark was caught in Malta by Alfredo Cutajar on 16 April 1987. This shark was also estimated to be around 7.13m (23.4ft) long by John Abela and has been designated as MALTA. However, Cappo drew criticism because he used shark size estimation methods proposed by J.E. Randall to suggest that the KANGA specimen was 5.8–6.4m (19–21ft) long. In a similar fashion, I.K. Fergusson also used shark size estimation methods proposed by J.E. Randall to suggest that the MALTA specimen was 5.3–5.7m (17–19ft) long. However, photographic evidence suggested that these specimens were larger than the size estimations yielded through Randall’s methods. Thus, a team of scientists—H.F. Mollet, G.M. Cailliet, A.P. Klimley, D.A. Ebert, A.D. Testi, and L.J.V. Compagno—reviewed the cases of the KANGA and MALTA specimens in 1996 to resolve the dispute by conducting a comprehensive morphometric analysis of the remains of these sharks and re-examination of photographic evidence in an attempt to validate the original size estimations and their findings were consistent with them. The findings indicated that estimations by P.Resiley and J.Abela are reasonable and could not be ruled out.]A particularly large female Great white nicknamed “DeepBlue”, estimated measuring at 6.1m (20ft) was filmed off Guadalupe during shooting for the 2014 episode of Shark Week “Jaws Strikes Back”. Deep Blue would also later gain significant attention when she was filmed interacting with researcher Mauricio Hoyas Pallida in a viral video that Mauricio posted on Facebook on 11 June 2015.Deep Blue was later seen off Oahu in January 2019 while scavenging a sperm whale carcass, whereupon she was filmed swimming beside divers. A particularly infamous great white shark, supposedly of record proportions, once patrolled the area that comprises False Bay, South Africa, was said to be well over 7m (23ft) during the early 1980s. This shark, known locally as the “Submarine”, had a legendary reputation that was supposedly well founded. Though rumours have stated this shark was exaggerated in size or non-existent altogether, witness accounts by the then young Craig Anthony Ferreira, a notable shark expert in South Africa, and his father indicate an unusually large animal of considerable size and power (though it remains uncertain just how massive the shark was as it escaped capture each time it was hooked). Ferreira describes the four encounters with the giant shark he participated in with great detail in his book “Great White Sharks on Their Best Behaviour’
Great white sharks have rows of teeth. The first two rows of the teeth are used for grabbing and cutting the prey they eat. Since large mammalian prey can be pretty tough to get through, a lot of teeth can be broken whilst eating. These teeth are vital to feeding and when one is broken it needs to be replaced immediately. This is why a Great white shark has multiple rows of teeth as the other teeth in the last rows are able to replace the front teeth as and when they are broken, worn down, or when they fall out.
Great white sharks have about two hundred and fifty teeth, arranged in five rows.
Seems like a standard question, but when you consider how much we don’t know about Great white sharks, such as where they give birth, you realise there are no easy answers where sharks are concerned. In order to tell you how many teeth a white shark has over its lifetime, we’ll need to do a calculation: Rate of tooth loss X average life span of the shark = how many teeth over a lifetime. They could lose up to 20 000 in a lifetime. It does not mean they all lose that amount just that some might.
Most sharks are ovoviviparous, including Great white sharks.
Ovoviviparous sharks have eggs that develop within the mother’s body. The eggs are fertilized internally and the developing sharks are nourished by the egg yolks. The young hatch within the oviduct and continue to receive nourishment from the remainder of the egg yolk, still attached to their body, as well as from fluids secreted into the oviduct. Some species of shark are cannibalistic, feeding on other eggs and embryos within the oviduct. Only a small number of these pups survive until birth. The young are then born live, and are fully functional.
It is believed that Great white sharks, like ragged tooth sharks, practise what is known as oophagy also known as inter-uterine cannibalism where the strongest and fiercest developing embryos eat the unfertilized eggs (potential siblings) for nourishment.
Sharks are born with teeth. Unlike humans, shark pups enter the world sporting a full set of teeth. This makes it easy for them to feed and fend for themselves, since there is no parental care. They are essentially born and right from their first moments are ready to go as perfect little predator pups.
A baby Great white sharks tooth is a lot narrower than an adult and is more suited to feeding on smaller sharks and fish and when they are really young their teeth are actually tri-cusped meaning that on either side of the base of each tooth there are two sharp little points.
When a Great white shark pup is born it will measure around 5 feet (1.3 to 1.5 meters) and weigh about 77 pounds (35 kilograms).
According to a 2014 study, the Great white sharks lifespan is as long as 70 years or more, well above previous estimates, making it one of the longest lived cartilaginous fishes currently known.
Great white sharks live in almost all coastal and offshore waters which have water temperature between 12 and 24 °C (54 and 75 °F), with greater concentrations in the US (North East and California), South Africa, Japan, Oceania, Chile and the Mediterranean including the Sea of Marmara and Bosporus. . In the open ocean, the Great white shark has been recorded at 3,900 feet. These findings challenge the traditional notion that the Great white is a coastal species.
The great white is an epipelagic fish, observed mostly in the presence of rich game, such as fur seals (Arctocephalus ssp.), sea lions, cetaceans, other sharks, and large bony fish species
A 2007 study used CT scans of a shark’s skull and computer models to measure the shark’s maximum bite force. The study reveals the forces and behaviours its skull is adapted to handle and resolves competing theories about its feeding behaviour. In 2008, a team of scientists led by Stephen Wroe conducted an experiment to determine the Great white shark jaw power and findings indicated that a specimen massing 3,324 kg (7,328 lb) could exert a bite force of 18,216 newtons (4,095 lb).
Great White Sharks do not have black, beady killer eyes. They actually have beautiful blue eyes. The iris of a white shark is not black; it’s a very dark blue.
Globally diving with Great white sharks without a cage is not done commercially: there are no tour operators on the planet who advertise this activity due to the risks involved.
It is unclear how much of a concurrent increase in fishing for Great white sharks has caused the decline of Great white shark populations from the 1970s to the present. No accurate global population numbers are available, but the Great white shark is now considered vulnerable. Sharks have a long interval between birth and sexual maturity making population recovery and growth difficult.
Unfortunately, no one has yet measured the swimming speed of a White Shark going flat-out. An analysis of White Sharks attacking a video camera-equipped surfboard off the South Farallon Islands, California, gave some indication of this animal’s attack speed. Current consensus among shark scientists is that the top swimming speed of the Great white is at least 25 miles (40 kilometres) per hour. My own rough, back-of-the-envelope-type calculations — using several methods — suggest that the White shark may achieve burst speeds of 35 miles (56 kilometres) per hour or more. That may not seem very speedy, but it’s seven times faster than the finest Olympic swimmer and probably at least ten times faster than you or I could manage.
Great white sharks are often thought of as the most fearsome predators in the ocean.
But even these sharks face threats that they are well aware of. A new study found that when Great white sharks have encountered killer whales, or orca near their hunting grounds, they’ve fled and stayed away for a short to medium term duration (4 to 8 weeks and longer). Killer whales are the only known species that hunt Great white sharks.
Great white sharks increase their body temperature by using a counter current heat exchange system, with overlapping arteries collectively known as the rete Mirabelle. It is a complex of arteries and veins lying very close to each other. The rete Mirabelle utilizes counter current blood flow within the net to act as a counter current exchanger. The rete Mirabelle is also known as the miraculous network.
Of the five hundred or so shark species found in the world’s oceans, only about two dozen are known as “obligate ram ventilators”,. This means they need to constantly force water across their gills in order to breathe, typically by swimming at speed or finding a fast moving current to remain in. These sharks are among the fastest, most formidable predators of the sea. The Great white shark and Mako shark are both obligate ram ventilators.
Sharks interestingly do not have a specific name for the different sexes although baby sharks are called pups.
It’s all in the Great White shark’s external anatomy. Male Great white sharks have modified pelvic fins called claspers which are used for mating. The claspers are like a pair of roll-up fins under their body towards the rear. Females do not have these claspers.
In addition, females tend to be larger than males, although this difference may not always be so obvious. The reason females are larger than males is because they need to have the capacity to carry 2 – 10 pups when pregnant. These pups can be as large as 1.5 meter at full term. That’s a lot of space that is required!
All sharks practice internal fertilization. Male sharks have paired reproductive organs called claspers, and female sharks have an opening called a cloaca. Often the male shark will bite onto the female to hold themselves steady during mating. This can be a difficult process with both sharks often ending up with wounds.
Male Great White sharks have paired reproductive organs called claspers, and female sharks have an opening called a cloaca. Fertilization occurs when a clasper is inserted into the cloaca and sperm is injected into the female. When mating begins, a male shark will mount a female shark, either swimming beside or underneath.
There has yet to be a sighting of Great White Sharks mating.