Great white shark
The great white shark (Carcharodon carcharias) is a species of shark. They are world's largest living predatory fish. Mature sharks may grow up to 6.4 m (21 ft) in length and 3,324 kg (7,328 lb) in weight. There also have been a few reports of great white sharks measuring over 8 m (26 ft). This shark reaches its sexual maturity around 15 years of age. The lifespan of great white shark may be as long as 70 years or more. Great white sharks can accelerate to speeds over 56 km/h (35 mph).
|Great white shark|
|Range (in blue); in the dark blue areas the sharks are more common|
Great white sharks have about 300 teeth, arranged in many rows. The first two rows of the teeth are used for grabbing and cutting the animals they eat, while the other teeth in the last rows replace the front teeth when they are broken, worn down, or when they fall out. The teeth have the shape of a triangle with jags on the edges. Great white sharks are carnivores. Great white sharks are apex predators. They eat fish, seals, sea lions, seagulls, penguins, squid, octopuses, dolphins, small whales, crabs, shrimps, stingrays, sea turtles and other sharks.
The great white shark has no natural predators other than the killer whale. Some orcas have discovered they can paralyse the shark by flipping it upside-down. Then they hold the shark still with their mouth, and that suffocates it (sharks get oxygen by moving through the water).
The bestselling novel Jaws by Peter Benchley and the film by Steven Spielberg show the great white shark as a "ferocious human eater". In real life, humans are not the preferred food of the great white shark. However, of all shark species, the great white shark has the second largest number of fatal unprovoked attacks on humans.
The great white shark is a shark. The great white shark is a shark and a type of cartilaginous fish belonging to a biological class known as Chondrichthyes. These fish are jawed vertebrates with paired fins, paired nares, scales, a heart with its chambers in series, and a skeleton made of cartilage not bone. These sharks are also known as Lamniformes, which is an order of sharks commonly referred to as Mackerel Sharks. This species of shark possess two dorsal fins, an anal fin, five gill slits and a mouth extended behind the eyes.
The great white shark is one of nature’s most deadly carnivores, and is distinguishable by their jaws and many sharp teeth. The difference is the ability for both the shark’s jaws to move when ambushing their prey. They will first bite with the lower jaw to sink its teeth in, then close the upper jaw and begin thrashing their heads repeatedly to tear off chunks of flesh . They may contain as many as 3, 000 teeth at one time, sitting in five rows with the largest set in the front. In the event a tooth is lost, another comes forward from a stash of backup teeth embedded in the shark’s jaws.
In addition to the teeth and jaws of great white sharks, their senses have greatly adapted to sharpen their skills as hunters. Their sense of smell is most accurate and great whites can detect a single drop of blood in ten billion drops of water. They possess an “ear stone” which helps the animal position itself in the water depending on the direction it is swimming. Sharks also utilize excellent vision with retinas divided into two areas for daylight and nighttime swimming, and protect them by rolling them backwards into the skull before biting. One of their most interesting senses relates to their touch and electro-reception. A series of pores in the shark’s nose allow them to detect electromagnetic fields and sense animal vibrations in the water, as well as accurately navigate through the open ocean.
The great white becomes an adult about nine years after its birth. The growth of the great white shark is about 25-30 centimetres per year and they grow to an average size of 4.5 meters. The largest can be as much as 6.4 meters in length. Their liver, a delicacy to killer whales, can weigh up to about 24 percent of its own body weight.
Where they liveEdit
Great white sharks live in the sea. They live near the coast, in all warm waters. They occasionally make dives into the deep water of open oceans. They can be in water as shallow as three feet deep, and as deep as 1,280 metres.[source?]
They may swim near:
- Western Atlantic: from Newfoundland to Florida, Bahamas, Cuba, Northern Gulf of Mexico, Brazil, Argentina, Guadeloupe;
- East Atlantic: France, Senegal, Ghana, Democratic Republic of the Congo
- Mediterranean: North Africa, South of France, West and South coast of Italy, Croatia, Malta, Greece, ;
- Indian Ocean: South Africa, Seychelles, Red Sea
- Western Pacific: Japan, Korea, China, Philippines, Australia, New Zealand;
- Central Pacific: Hawaii
- Eastern Pacific: from Alaska to California, and from Panama to Chile.
Research has shown that the sharks of northern California are genetically different to other shark populations. DNA evidence shows the population separated from other great whites about 200,000 years ago (during the Pleistocene Era). By tagging the sharks they also learned that they are generally alone, but follow the same route through the ocean, and stay in the same places. From January to July they live near Hawaii, and then move to Californian waters between August and December.
Sometimes, sharks attack human beings. When sharks see a new object, for example, a surfboard, they bite it to know what kind of object it might be. Sometimes, sharks see the shadow of surfers and attack them because they think they are seals.
Some people think that humans are not good food for great white sharks, because the sharks' digestion might be too slow to cope with the human body's high ratio of bone to muscle and fat. It might be argued that because of this nearly all attacks by great whites do not continue after the first bite.[source?]
Sharks are opportunistic predators. This means that they are not very picky on what they feed on. This behaviour has been observed when the animals completely consumed piecemeal bait. The explanation given is that the tactics generally involve biting prey once, so that the prey bleeds to death before the shark moves in to feed. Other large mammals, such as seals and dolphins also seem to have this tactic, as it minimizes the risk of the predator injuring itself. In most cases, humans tend to escape quickly after the first bite so that they are not consumed, simply bitten. Deaths in such cases are generally caused by loss of blood from the first wound. In cases where attacks have occurred and the victim has been unable to escape quickly, partial or whole consumption has occurred; lone divers are especially at risk of this. Most attacks also seem to occur in waters where it is hard to see or where the shark is confused, but this is unlikely given that the shark is in its natural hunting environment with highly developed senses.[source?]
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- Great white shark from ARKive
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