What does a great white shark look like? Great white shark: enemy or victim? Feeding of an aquatic predator

From this article you will learn how long do sharks live. Sharks are one of the most interesting ocean representatives. They have inhabited the depths of the sea for more than five hundred (500) million years.

Instant reply: currently there are about one hundred ( 100 ) shark species. Different representatives of these creatures differ in life expectancy. Long-lived sharks can live over 80 years(for example, a whale shark).

How long do sharks live - in detail by species

Sharks are ancient representatives of our planet. The fact is that these animals inhabited the Earth more than 450 million years ago. Some varieties have hardly changed over such a huge period of existence.

• Centenarians- polar sharks. Their age can exceed one hundred years, and according to scientific research - even 200. This is due to an incredibly weak metabolism. Researchers believe that this is one of the longest-living animals on our planet to date.

• Lifespan of a whale shark - up to 75 years.

• The lifespan of a basking shark is approximately 50 years.

• The white shark lives much shorter - up to 30 years.

• Very rare species- a largemouth shark can survive up to 50 years, and its long-livers are up to one hundred years. But this cannot be confirmed in any way, since since its discovery in 1976, only a couple of dozen representatives of this species have been identified.

• Life expectancy is enormous hammerhead shark sometimes it can be about 50 years.

• The Mako shark is one of the most hot-tempered and evil species sharks Its maximum lifespan may be slightly longer 30 years for females and slightly less for males.

How long do sharks live - Polar

Not long ago, ichthyologists noticed an amazing feature according to which those living in colder water live longer among sharks.

This applies specifically to polar sharks. They believe that for them the indicator is a hundred years is not the limit at all, and such representatives of sharks are able to live longer. Exactly how many is not yet clear due to the difficulty of identifying ages.

Arctic sharks have an incredibly slow metabolism, they seem to live in a dream, which is why they are called sleepy sharks.

Second position occupied by large species of sharks, which is natural, because for all living things one can notice this law: larger types live longer than small ones. They need more time to grow. In the tropics, the average lifespan of sharks is up to 30 years, and in middle latitudes - up to 45 years.

How long do white sharks live?

Researchers recently concluded that white sharks can live much longer than previously thought. Using the latest technology to clearly determine the age of shark tissue, researchers were able to identify a male white shark that lived up to 70 years old.

According to scientists, such a discovery is incredibly important for animal protection, since data on the lifespan of the type, the speed of its development and the time it reaches puberty will help create programs for the conservation of the species.

Previously, researchers tried to determine the age of a predator by counting growth rings in tissue (for example, in a vertebra). But the shark skeleton contains cartilage, and the division between the rings is difficult to discern even with a microscope.

Currently, researchers have been fortunate to identify a radioactive marker in certain rings.

This marker is an isotope that fell into the ocean simultaneously with sediments after atomic bomb tests in the 60s. It settled in the tissues of animals that lived at that time.

The researchers used traces of radioactive carbon in the form of some kind of stamp, with which they can calculate and calibrate the tissue layers in order to then more accurately determine the age of the samples obtained.

Past examinations of animal remains from the Indian and Pacific oceans have led researchers to believe that white sharks live for about 30 years.

But the radioactive marker significantly increased this indicator: the largest male lived 73 years old, and the female − 42 . All animals lived in the Atlantic Ocean, but scientists do not believe that there is any significant difference in the life expectancy of sharks from other oceans.

If the hypothesis that the average lifespan of a white shark is 70 years, will be confirmed, it will be possible to call this species one of the most long-lived types of cartilaginous fish. But at the same time, the white shark is one of the most vulnerable inhabitants of nature, since it is one of the main hunting items.

And if sexual maturity in such sharks occurs very slowly, then it will be quite difficult for them to restore their numbers after any significant damage.

In addition, as scientists have already learned, white sharks are far from the most prolific of the great variety of cartilaginous fish - the female is capable of producing only a couple of cubs in the litter(researchers still have not figured out how many times a female white shark can give birth during her life).

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The great white shark - Carcharodon is considered the largest shark in the world, since its body length is about eight meters, and this shark weighs almost three tons.

The great white shark lives in the World Ocean in coastal waters with temperatures not lower than 12°C. This ocean predator avoids desalinated and low-salt seas. This shark is especially common off the coast of California.

Representatives of this genus of sharks are capable of moving long distances and diving to depths of up to 1300 meters.

The white shark is called due to its very light belly, which makes the shark invisible to the inhabitants of the ocean depths in the thickness of the ocean. The coloration of the fish's upper body blends in with the surface ocean waters and also allows the shark to remain undetected.

Carcharodon is another name for a shark, reflecting its features, which comes from the Greek words: “karcharos” and “odous”, which means “sharp tooth”. A truly great white shark is the owner of a huge mouth, studded with five rows of triangular five-centimeter teeth, equipped with jagged edges. The shark uses its upper teeth to tear its prey apart, and uses its lower teeth to hold it.

The mouth of this shark is so huge that eight adults could easily fit in it. Therefore, the shark does not chew its food thoroughly, but swallows it in large pieces, the weight of which can reach up to 70 kg, which is equal to the average weight of a person. If the prey is small in size, the shark swallows it whole.

The big shark is not particularly picky about food. Along with large marine inhabitants, small marine inhabitants can also become its prey. Carcharodon does not refuse carrion and all kinds of waste. Pieces of a horse, a whole dog, a leg of lamb, a pumpkin, a bottle and other refuse were found in the stomachs of individual caught specimens.

In Australia, the great white shark is called the “white death”. And this name also justifies itself, since this shark is capable of attacking people swimming in the ocean or sea more often than its other relatives.

Perhaps the shark’s aggressive behavior is due to its coastal habitat. A shark attacks a man, mistaking him for his usual prey, most likely a seal. In most cases, sharks seriously injure a person and do not try to eat him, but simply spit him out. However, injuries from great white shark attacks are often incompatible with life, which is why this shark is considered a man-eating shark.

All organs of a predator are designed to kill. Thanks to its excellent sense of smell, the great white shark is able to smell at a distance of about 600 meters. Its eyes are designed like a cat's, so the shark can navigate perfectly in the dark. The lateral line is a sensory organ inherent in all fish, allowing the shark to detect the slightest fluctuations in water 115 meters from its location.

The shark begins to engage in killing even in the embryonic state, when it absorbs its weak sisters and brothers long before its birth. Therefore, a female great white shark gives birth to only 1 or 2 cubs, which grow very slowly and become sexually mature at 12–15 years.

The characteristics of the low fertility of the white shark and the duration of puberty have become one of the reasons for the reduction in the number of these marine predators to 3,500 individuals. Therefore, despite its bad temper, the great white shark needs protection.

Video: Great white shark (lat. Carcharodon carcharias)

Since ancient times, people have had a strong desire to see the best of everything - for example, a photo showing the largest white shark. But such a photo is extremely difficult to take.

There are many reasons. Among them are the difficulties of detecting a particularly large predator, choosing the optimal angle, insufficient visibility in ocean water, and the danger that accompanies contact with a shark.

Unlike sea animals, known for their curiosity and sociability, they will consider an unknown object from the point of view of its edibility/inedibility.

Some individuals of great white sharks still grow to sizes unattainable by another marine predator - the killer whale (Orcinus orca). Killer whales reach a maximum length of 10 meters and a weight of 7 tons (they are “thicker”); The maximum length of white sharks has not been precisely established.

Who is the Great White Shark?

Sizes of the largest white sharks

The exact lifespan of great white sharks is unknown - it is not possible to observe them for a long time.

Scientists consider the greatest age of white sharks to be 70-100 years. If the maximum lifespan of predators is really equal to a century, then the size of a 100-year-old shark should be simply enormous and figures of 10-12 meters would not be at all extreme.

The original photos, where the largest white shark lies dead weight at the feet of fishermen, are dated 1945: the caught shark weighed about 3 tons, its length was 6.4 meters.

True, there is one point here - the bodies of sharks caught and removed from the water quickly lose moisture, i.e. shrink, decreasing in size and weight. Therefore, the results of measurements taken immediately after the capture of a predator and after some time do not coincide - the difference can be up to 10%.

Photo: The largest white shark

For humans, this is just a loss or gain of profit; for marine life, this is a real threat of extinction in any case.

A great white shark can reach large sizes with age and only under favorable conditions: an abundance of food, an absence of enemies and favorable water temperatures. But these opportunities are becoming fewer and fewer every year...

White shark (Carcharodon carcharias)

general description

The white shark (Carcharodon carcharias), which is more correctly called Carcharodon, reaches particularly significant sizes - the largest of the modern predatory sharks. Its back and sides are gray, brown or black, and its belly is off-white. The largest specimen of this species measured was 11 m in length, although even larger specimens appear to occasionally occur. The usual size of a white shark is 5-6 m with a weight of 600-3200 kg. At the same time, sharks about 4 m long have not yet reached sexual maturity. It is interesting to note that until relatively recently (at the end of the Tertiary period) there were white sharks (species Carcharodon megalodon), reaching about 30 m in length.

Eight people could easily fit in the mouth of such a shark. The modern white shark leads a solitary lifestyle and is found both in the open ocean and off the coast. This shark usually stays near the surface, but can descend into the deep layers of water: one specimen was caught even at a depth of about 1000 m. The white shark is widespread in the warm waters of all oceans, and is also found in moderately warm waters. Its occurrences have been noted, in particular, in the southern part of the Sea of ​​Japan, off the coast of Washington state and California, on the Pacific coast of the United States, and even off the island of Newfoundland.

This species is characterized by very large (up to 5 cm in height) and wide teeth, triangular in shape and roughly serrated along the edges. The very powerful armament of the jaws gives the white shark the ability to inflict terrible damage on its prey and bite through the bones and cartilage of the victims without much effort, and the wide mouth and pharynx allow this giant shark to swallow very large pieces. Apparently, the white shark is not particularly picky in its choice of food, although most often other sharks were found in the stomachs of caught individuals, which it apparently preys on. In this case, relatively small sharks (sometimes exceeding 2 m in length) are usually swallowed intact, while larger ones, such as a giant shark, are torn into pieces.

Carcharodon's food also includes relatively small fish (mackerel, sea bass), tuna, seals, fur seals, sea otters, and sea turtles. This shark does not even disdain carrion and waste: in the stomach of one specimen, caught near Sydney, pieces of a horse, a dog and a leg of lamb were found among other food, and in another, caught off the coast of South Africa, half a kid, two pumpkins and a bottle of wicker case. The white shark is one of the sharks most dangerous to humans. There have been many recorded cases of this shark attacking people in the water, as well as boats.

In recent years alone, more than 100 such attacks have been documented, and this is undoubtedly only a small part of them. Most attacks were fatal, and only a few victims were lucky enough to save their lives, escaping with the loss of a limb or other serious injuries. White shark attacks have been recorded not only in open waters, but also near the coast - in bays and on beaches. It is not for nothing that in Australia this shark is called the “white death”. It is believed that attacks on humans are carried out only by individual “stray” individuals of this species. So, in 1916, off the Atlantic coast of America (New Jersey), five people were attacked by a shark off the coast over the course of 12 days. Only one of them survived. After a white shark was caught in the area, the attacks stopped.

Scientific Classification

Kingdom: Animals
Type: Chordata
Class: Cartilaginous fish
Superorder: Sharks
Order: Lamniformes
Family: Herring sharks (Lamnidae)
Genus: White sharks (Carcharodon)

Origin

The great white shark (Latin Carcharodon carcharias) - also known as the white shark, white death, man-eating shark, Carcharodon - is an exceptionally large predatory fish found in the surface coastal waters of all the Earth's oceans except the Arctic.

Great white shark This predator owes its name to the white color of the abdominal part of the body, with a broken border on the sides separated from the dark back.

Reaching a length of over 7 meters and a mass of over 3,000 kg, the great white shark is the largest modern predatory fish (not counting the plankton-eating whale and basking sharks).

In addition to its very large size, the great white shark has also acquired a notorious reputation as a merciless cannibal due to numerous attacks on swimmers, divers and surfers. A person has much less chance of surviving an attack by a man-eating shark than under the wheels of a truck. A powerful moving body, a huge mouth armed with sharp teeth and a passion for satisfying the hunger of this predator will leave the victim no hope of salvation if the shark is determined to profit from human flesh.

The great white shark is the only surviving species of its genus Carcharodon. It is on the verge of extinction - there are only about 3,500 specimens left on Earth.

The first scientific name, Squalus carcharias, was given to the great white shark by Carl Linnaeus in 1758. Zoologist E. Smith in 1833 assigned the generic name Carcharodon (Greek karcharos sharp + Greek odous - tooth). The final modern scientific name of the species came into being in 1873, when the Linnaean species name was combined with the genus name under one term, Carcharodon carcharias.

The great white belongs to the herring shark family (Lamnidae), which includes four other species of marine predators: the mako shark (Isurus oxyrinchus), the longfin mako shark (Longfin mako), the Pacific salmon shark (Lamna ditropis) and the Atlantic herring shark (Lamna nasus).

The similarity in the structure and shape of the teeth, as well as the large size of the great white shark and the prehistoric megalodon, has led most scientists to consider them closely related species. This assumption is reflected in the scientific name of the latter - Carcharodon megalodon.

Currently, some scientists have expressed doubts about the close relationship of Carcharadon and Megalodon, considering them to be distant relatives belonging to the family of herring sharks, but not so closely related. Recent research suggests that the white shark is closer to the mako shark than to the megalodon. According to the theory put forward, the true ancestor of the great white shark is Isurus hastalis, while megalodons are directly related to sharks of the species Carcharocle. According to the same theory, Otodus obliquus is considered a representative of the ancient extinct branch of Carcharocles megalodon olnius.

Photo White shark (click to enlarge):

Distribution and habitats

The great white shark lives throughout the world in coastal waters of the continental shelf, the temperature of which ranges from 12 to 24 degrees Celsius. In colder waters, great white sharks are almost never found. They also do not live in desalinated and slightly salted seas. For example, they were not found in our Black Sea, which is too fresh for them. In addition, there is not enough food in the Black Sea for such a large predator as the great white shark.

Habitat of the great white shark

The habitat of the great white shark covers many coastal waters of the warm and temperate seas of the World Ocean. The above map shows that it can be found anywhere in the middle ocean belt of the planet, except, of course, the Arctic Ocean. In the south they are not found further than the southern coast of Australia and the coast of South Africa. Great white sharks are most likely to be found off the coast of California, near the Mexican island of Guadalupe. Individual populations live in the central part of the Mediterranean and Adriatic Seas (Italy, Croatia), off the coast of New Zealand, where they are protected species. Great white sharks often swim in small schools.

One of the most significant populations has chosen Dyer Island (South Africa), which is the site of numerous scientific studies of this species of shark. Great white sharks are relatively common in the Caribbean Sea, off the coast of Mauritius, Madagascar, Kenya and near the Seychelles. Large populations persist off the coasts of California, Australia and New Zealand.

Carcharodons are epipelagic fish, their appearance is usually observed and recorded in coastal seas, abundant in prey such as seals, sea lions, whales, where other sharks and large bony fish live. The great white shark is nicknamed the mistress of the ocean, since no one can compare with it in the power of attacks among other fish and sea inhabitants. Only the large killer whale terrifies Carcharodon. Great white sharks are capable of long-distance migrations and can descend to considerable depths: these sharks have been recorded at depths of almost 1300 m.

Recent research has shown that great white sharks migrate between Baja California, Mexico, and a spot near Hawaii known as the White Shark Cafe, where they spend at least 100 days a year before migrating back to Baja California. Along the way, they swim slowly and dive to a depth of approximately 900 m. After arriving at the coast, they change behavior. Dives are reduced to 300 m and last up to 10 minutes.

A white shark tagged off the coast of South Africa has revealed its annual migration route to the southern coast of Australia and back. Researchers have found that a great white shark completes this route in less than 9 months. The entire length of the migration route is about 20 thousand km in both directions.

These studies refuted traditional theories, according to which the white shark was considered an exclusively coastal predator.

Interactions have been established between different populations of white sharks, which were previously considered separate from each other. The purposes and reasons why the white shark migrates are still unknown. There are suggestions that migrations are caused by the seasonal nature of hunting or mating games.

Photo White shark (click to enlarge):

Anatomy and appearance

The body of the great white shark is spindle-shaped, streamlined in shape. A large, conical head with medium-sized eyes and a pair of nostrils located on it, to which small grooves lead, increasing the flow of water to the olfactory receptors of the shark. The number of teeth in the great white shark, like in the tiger shark, 280-300. They are located in several rows (usually 5). The body color of great white sharks is typical of fish swimming in the water column. The ventral side is lighter, usually dirty white, the dorsal side is darker - gray, with shades of blue, brown or green. The large and fleshy dorsal fin, two pectoral and anal fins are located on the body of the great white shark in places usual for sharks. The plumage ends with a large caudal fin, both blades of which, like all salmon sharks, are the same size.

Dimensions

The usual size of an adult great white shark is 4-5.2 meters with a weight of 700 - 1000 kg. Females are usually larger than males. The maximum size of a white shark is about 8 m and weighs more than 3500 kg. It should be noted that the maximum size of a white shark is a hotly debated topic. Some zoologists and shark specialists believe that the great white shark can reach significant sizes - more than 10 or even 12 meters in length.

Among the features of the anatomical structure, it should be noted that great white sharks have a highly developed circulatory system, which allows them to warm up their muscles, thereby achieving high mobility of the shark in the water. Like all sharks, great whites lack a swim bladder, meaning they must constantly move to avoid drowning. Although, it should be noted that sharks do not feel any particular inconvenience from this. For millions of years they managed without a bubble and did not suffer from it at all.

The great white shark is the only surviving species of its genus Carcharodon. It is on the verge of extinction. The white shark is a nurse and a regulator of the number of other organisms.

Photo White shark (click to enlarge):

Nutrition

Great white sharks are predators, and primarily feed on fish (including rays, tuna and smaller sharks), dolphins, whale and pinniped carcasses such as seals, fur seals and sea lions, and occasionally sea turtles. At times they attack sea otters and attack penguins, although this happens very rarely. It is also known that these sharks are not able to digest food. Most of the four-meter white shark's diet consists of mammals. These sharks prefer prey that is high in energy-rich fat. Shark researcher Peter Klimley used seal, pig and sheep carcasses as bait in his experiments. The sharks attacked all three baits, but rejected the sheep carcass.

The great white shark is a predator whose only real threat is humans. Although the white shark's diet overlaps with that of killer whales, they do not compete directly. However, in one famous incident, a female killer whale killed a pre-adult white shark, after which her calf feasted on the shark's liver. Small pods of dolphins are capable of killing a great white shark through a mob attack in which the dolphins ram the shark.

Great white sharks' reputation as ferocious predators is well deserved, but they are by no means indiscriminate eaters (as was once believed). The ambush hunting technique, when a shark attacks its prey from below, is typical for them. Near the now famous Seal Island, in South Africa's False Bay, studies have shown that shark attacks most often occur in the morning, within two hours of sunrise. The reason for this is that at this time it is very difficult to spot a shark near the bottom. The attack success rate is 55% in the first 2 hours, it drops to 40% late in the morning and then the sharks stop hunting.

The white shark's hunting technique varies depending on the species it preys on. While hunting seals near South Africa, a great white shark ambushes the seal from below and strikes the seal in the midsection at high speed. They move so fast that they actually emerge from the water. After an unsuccessful attack, she can continue to pursue her prey. As a rule, the attack occurs on the surface of the water.

When hunting northern elephant seals near California, the great white shark immobilizes its prey by biting the hindquarters (which is the elephant seal's main source of movement) and then waits until the prey dies from blood loss. This technique is usually used when hunting adults, which can be larger in size than a shark and are potentially dangerous opponents.

When hunting dolphins, white sharks attack them from above, behind or below to avoid detection through the echolocation that dolphins use.

Photo White shark (click to enlarge):

Behavior

The behavior and social status of the white shark are not well understood, but a recent study suggests that white sharks are more social than previously thought. In South Africa, white sharks appear to have a hierarchy of command based on size, gender and privilege. Females dominate males, larger sharks dominate smaller sharks, and long-time residents dominate new arrivals. When hunting, white sharks tend to maintain a large interval between each other, and resolve all conflict situations among themselves by resorting to ritual performances. They rarely resort to bites during these battles, although some individuals have been found to have bite marks left by other white sharks. It can be assumed that when someone invades their personal space, the white shark gives the intruder a warning bite. Some experts think that the white shark delivers gentle bites to other individuals, thus demonstrating to them its superiority.

The great white shark is one of several shark species that regularly raises its head higher
sea ​​surface to peer closely at other objects such as prey. This behavior has also been observed in at least one group of reef sharks, but in this case it may have been driven by human interest (sharks are better at picking up odors this way because they travel faster through air than through water). Sharks are very curious animals and can show a high degree of intelligence and
individuality when conditions allow it.

Photo White shark (click to enlarge):

Reproduction

Any living creature strives to produce offspring similar to itself, which will continue the existence of the species, genus, family and will not allow this family chain to disappear in the ruthless battle of evolutionary selection. Each generation, according to Charles Darwin’s theory, is endowed with increasingly reliable survival mechanisms. For many millions of years, sharks, without a moment’s respite, defended their right to exist in the seas of our planet. So far they have succeeded and are succeeding quite well. What is the mechanism of reproduction of their own kind in these amazing fish?

Sharks, like all cartilaginous fish, reproduce by internal fertilization, when the male's reproductive products are introduced into the female's body and fertilize her reproductive products. However, in different species of sharks, the reproductive process may differ, primarily in the way the offspring emerge from the mother's egg. There are oviparous, ovoviviparous and viviparous sharks.

Oviparous sharks reproduce by eggs enclosed in a hard, sometimes covered with outgrowths, protein shell, on top of which there is usually a horny protective layer. Oviparous polar shark The shell on the eggs is formed during passage through the oviduct through the female's albumin and shell glands. It protects the embryo from dehydration, eating by predators, mechanical damage, and allows groups of eggs to be suspended on algae. The eggs of oviparous sharks are large and contain a lot of nutritious yolk. Usually, from 1-2 to 10-12 eggs are laid at a time, and only the polar shark lays up to 500 large eggs at a time, resembling goose eggs, about 8 cm long. The eggs of the polar shark are not enclosed in a cornea, unlike the eggs of other oviparous species sharks The embryonic development of the embryos is slow, but the hatched baby shark differs from the adult only in size and is capable of independent life.

More than 30 percent of all known shark species are oviparous. These are mainly bottom-dwelling representatives of the shark tribe that live off the coast, although there are exceptions (polar shark). The method of reproduction of sharks by oviposition is similar to the reproduction of many reptiles and even birds.

In ovoviviparous sharks, which include the majority of modern species (more than half), the egg develops in the body of the female. The hatching of offspring also occurs there. You can imagine this process as the birth of a fry from an egg that did not have time to leave the female’s body. In this case, the cubs hatch and remain inside the mother for some time, eventually being born well developed and adapted for independent existence. In some species of sharks, after using their yolk sac, the young eat unfertilized eggs accumulated in the uterus and even eggs from which their brothers and sisters did not have time to hatch. This phenomenon is called "intrauterine cannibalism." Such “cannibals” include sand, herring and some other species of sharks. As a result of such intrauterine selection, the strongest and most developed cubs are born, although their total number in the litter is not large.

A pair of sharks The period of gestation in ovoviviparous species of sharks has not been precisely determined by scientists. It is believed to range from several months to 2 years (katran), which is one of the longest gestation periods of any vertebrate.

Apparently, the method of reproducing offspring by ovoviviparity is, in a rough sense, a transition from reproduction by eggs to viviparity. Although, it is quite possible that nature provided just such a mechanism of reproduction for some species of animals, it did not receive further development during the evolutionary revision. However, the method of reproducing offspring by ovoviviparity in sharks and rays has existed for many millions of years and is still used today, i.e. is a fairly reliable reproduction mechanism.

Species of sharks that reproduce by ovoviviparity include, for example, the giant shark, which every two years brings 1-2 offspring of 1.5-2 meters each, the tiger shark, which gives birth to up to 50 sharks annually. This is apparently the maximum fecundity among ovoviviparous sharks.

During a live birth, an embryo develops in the female’s body, receiving nutrition from the mother’s circulatory system. The yolk sac, after using the yolk, grows to the wall of the female’s uterus, forming a kind of placenta, and the embryo receives oxygen and nutrients from the mother’s bloodstream through osmosis and diffusion. This method of reproduction already corresponds to the method of reproduction of higher animal organisms. There are also intermediate options between ovoviviparity and viviparity.

Just over 10 percent of existing shark species reproduce by viviparity. These include frilled shark, blue shark, some species of hammerheads, mustelids, saw sharks and many types of gray sharks. So, for example, the litter of a female frilled shark can number from 3 to 12 babies, in blue and hammerhead sharks their number can reach up to three dozen, in a long-finned oceanic shark - no more than ten.

Males have paired testes, which are suspended in the liver area on special stretch marks - mesenteries. The ducts of the seminiferous tubules of the testes (vases deferens) lie in the mesentery and empty into the renal tubules of the anterior narrow part of the kidney. This part of the kidney does not function as an excretory organ, but is converted into an appendage of the testis. The testicular tubules of a male shark open into the so-called Wolffian canal, which functions as a vas deferens. In the very rear part of the vas deferens, in sexually mature males an expansion is formed - the seminal vesicle.

The vas deferens on the right and left sides of the male’s body open into the cavity of the urogenital papilla. Next to them, openings of thin-walled hollow outgrowths - seed sacs - open in the same place. These are the remains of the so-called Müllerian canals. The ureters also empty into the cavity of the urogenital papilla. The urogenital papilla opens into the cavity of the cloaca with an opening at its apex. The formation of male germ cells occurs in the testicular tubules. Not yet mature spermatozoa enter the appendage of the testis - the anterior part of the kidney - through the seminiferous tubules and mature in its tubules. Mature sperm pass through the vas deferens and accumulate in the seminal vesicles and seminal sacs. When the muscles of the walls of the seminal vesicles and sacs contract, sperm are squeezed into the male's cloaca, and then, with the help of copulatory organs (pterygopodia), are introduced into the female's cloaca. Pterygopodia are formed from the rays of the ventral fins of the male; females do not have these formations.

The reproductive and urinary tracts of females are separated along their entire length. Females have paired ovaries, which are located in the shark’s body in much the same way as the testes of males. In immature females, the ovaries even resemble the testes of males in appearance.

The Wolffian canal in females performs only the function of the ureter. Müllerian canals are laid on the abdominal surface of the corresponding kidney. In most sharks, the anterior ends of the Müllerian canals, which perform the function of oviducts in females, go around the anterior end of the liver and, merging, form a common funnel of the oviduct, which lies at the ventral surface of the central lobe of the liver and has wide fringed edges. In some species of sharks, each female oviduct ends in a funnel. In the area of ​​the anterior part of the kidneys, each oviduct forms an extension - a shell gland, which is highly developed only in sexually mature individuals. The extended posterior part of the female's oviduct is called the "uterus". The oviducts of the right and left sides open into the cloaca with independent openings on the sides of the urinary papilla.

It should be noted that there is a certain unpleasant moment for the female during the process of mating with a male in many species of sharks. Literally male. rapes the female, brutally holding her by the fins and other parts of the body with his teeth during mating. Such “love caresses” often leave scars and numerous injuries on the body and fins of female sharks.

Internal fertilization, common to all sharks. Large eggs with significant reserves of nutrients and a strong shell, ovoviviparity and viviparity in many shark species sharply reduce embryonic and postembryonic mortality of offspring. This is very important, since sharks cannot be as careless about reproduction as most bony fish, which reproduce by laying thousands and even millions (sunfish) of eggs. However, most parent sharks cannot be called caring “ancestors” - newborn sharks that did not have time to hide in time can be happily eaten by a hungry mother.

Interestingly, in some species of sharks, cases of parthenogenesis have been observed, when the female gave birth to offspring without the participation of a male individual. Apparently, this is a kind of protective mechanism against the extinction of the species due to reproduction without the participation of males.

Similar cases have been reported in some aquariums, i.e. when keeping a female in captivity.

Photo White shark (click to enlarge):

Relationship with people

One of the most dangerous inhabitants of the seas and oceans is the white shark, a video of which is available on the website. The powerful jaws of Carcharodon are armed with sharp triangular teeth. Hard fangs are capable of not only tearing flesh, but also crushing strong bones.

It is not surprising that this predator can handle not only fish and squid, but also such strong animals as seals and elephant seals. An attacking white shark delivers a devastating bite, and then, shaking its head from side to side, tries to inflict as severe wounds on the victim as possible.

In this way, she completely demoralizes her prey, suppressing its will to resist. At the same time, the hunter does not forget about caution and her own safety. When lunging at a seal, the shark rolls up its eyes to protect them from its sharp claws. If the opponent is especially strong, then the carcharodon can release the prey after the first powerful bite and wait until the victim is exhausted from loss of blood.

This tactic helps the white shark successfully hunt pinnipeds. Interestingly, young predators learn mainly from their own experience. At first they attack the seals horizontally, but then they realize that it is better to deliver the decisive blow from below. In this case, the cat has much less chance of escaping danger.

Carcharodon's coloration helps it successfully camouflage itself before it attacks. A large white shark in video footage of a sea lion hunt appears completely unexpectedly, jumping several meters out of the water and simultaneously capturing prey with its powerful jaws.

It seems that the seal has no chance of salvation at all. However, in reality this is not the case. If a potential prey notices an attacking predator in time, it can escape the attack into the “dead zone” above the shark’s dorsal fins. In this case, the missed carcharodon temporarily loses sight of the prey, and it has the opportunity to escape.

Why is the white shark a very dangerous predator?

The white shark is not only the largest, but also one of the fastest among all its close and distant relatives. It develops high speed of movement not only thanks to its streamlined spindle-shaped body and powerful fins.

A special network of blood vessels allows you to saturate the muscles with oxygen as efficiently as possible. Due to this, over short distances, Carcharodon can develop particularly high speeds. However, such jerks require large amounts of energy, to replenish which you need fatty and high-calorie foods.

Therefore, it cannot be said that a person is of any gastronomic interest to a white shark. Typically, carcharodon attacks on people are either the result of accident or are provoked.

We can see a white shark in the video attacking a cameraman in a cage. Although the structure is intended for protection, the scuba diver feels very uncomfortable when the predator hits the bars with powerful blows. But it wasn’t the shark that swam to the beach, it was the observers with their cage, equipment and bait that invaded the underwater world.

Of course, large selachians are dangerous predators. And the most formidable of them is the white shark, which has a reputation as a man-eating shark. However, in their normal habitat, these predators do not interact with humans in any way. The white shark gained its sad popularity primarily thanks to horror films, where it is presented as a ruthless, bloodthirsty killer.
White sharks and relationships with people

Documentary films shot in recent years show that this is not at all the case. The white sharks in the video lead a normal daily life, hunting mainly for fish and pinnipeds.

If people invade their habitat, then the reaction of predators depends primarily on human behavior. In the video footage, you can see how white sharks react peacefully to scuba divers who behave respectfully towards them.

Photo White shark (click to enlarge):

Of all the possible marine predators, the great white shark has caused a huge amount of speculation and gossip. By the way, about half of them are nothing more than fantasies of frightened people. But the shark does not give up. Throughout its existence, it has confirmed its title as a superpredator.

Classification

The great white shark was first classified by Carl Linnaeus in 1758. He identified it as Squalus carcharias. However, this classification did not take root. Already in 1833, another scientist - Smith - identified the shark as Charcharodon. This generic name was derived from the Greek words charcharos (sharp) and odous (tooth).

The great white shark received its final classification in 1873. The international scientific name of the shark is Charcharodon carcharias. As we can see, it appeared as a result of combining the names given by both Linnaeus and Smith.

Spreading

Most divers would like to know where the great white shark is. Some are interested in this question because they want to avoid meeting the largest predatory fish in the world at all costs. Others, on the contrary, dream of swimming with Carcharodon at least once. We are forced to disappoint the first and delight the second: the predator lives in all the oceans of the planet. The only exception is the cold waters of the Arctic Ocean.

But the great white shark prefers tropical and temperate seas, living in the open sea around the continental shelf. The ideal temperature for sharks to live and reproduce is 12-24 °C. The salinity level of the water is also of great importance. Thus, in seas with low-salinity water it is impossible to meet a predator. This explains, for example, the fact that the shark does not swim into the Black Sea, although in the neighboring Mediterranean there are more than enough of these predatory fish. It is also found in the Adriatic Sea, as well as around the northern coast of Spain. Despite its dislike of cold water, the predator was seen in the Atlantic Ocean even off the coast of Nova Scotia. As for the Pacific Ocean, the shark even swims to the shores of Australia. It is necessary to clarify that the predator does not lead a sedentary lifestyle. It is in constant motion and migrates from one coast to another, the distances between which can reach a thousand kilometers.

Appearance

Of the more than 400 species of these predatory fish, the great white shark is the most equipped. Carcharodon's physical attributes are impressive. She has well-developed vision, hearing, smell, taste and tactile sensations, and even electromagnetism. Its body is spindle-shaped with a gray or lead-gray back and a white belly. Such colors are a natural camouflage necessary for the predator to blend into the environment during an ambush. It must be said that the larger the size an individual reaches, the lighter its color. Some may be completely lead-gray in color.

The white shark is able to determine the level of salinity of the water, as well as its chemical composition and feel their changes. This is possible thanks to special receptors that are located on the head, back and along the sides of the fish.

The sensitivity of Carcharodon's sense of smell is quite high. This is facilitated by small grooves around the nostrils of the predator. They increase the speed at which water flows into the nostrils.

The speed and mobility of the predator is ensured by the high degree of development of the circulatory system. Such natural data help the shark to quickly warm up its muscles. This is especially important given that it must be in constant motion. Otherwise, she would have drowned, because the predator lacks a swim bladder.

The size of the great white shark is impressive. It reaches 4-5 meters in length. The maximum size of a shark, which scientists call, is 8 meters. It is this figure that is accepted among most ichthyologists. However, some of them are sure that the shark can even reach 12 meters in length. The photo of the largest white shark ever seen by man is provided below. Its length was 11.2 meters.

The average weight of a great white shark is a ton. However, this is not the limit. The record weight is considered to be 3.5 tons. But the largest weight among sharks caught by humans was that of a predator caught more than half a century ago off the coast of Australia (1208.3 kg).

The lifespan of a great white shark is insignificant considering its physical characteristics: only 27 years.

Jaws

One of the most striking systems in a shark's body is its jaws. They are the best suited to kill. At one time, the shark tears off a piece of meat that can weigh 30 kilograms.

The animal has several jaws. Their number may vary depending on the age and lifestyle of the predator. The giant great white shark can even have seven rows of teeth. Although there are individuals whose jaws have only three rows.

The first, outer jaw has about 50 teeth. The lower one serves to hold the victim in place and prevent him from leaving. The front teeth of the upper jaw act as knives, with the help of which the predator can cut off huge pieces of meat. Her blow reaches a force of 318 kg.

In order to fully understand why a shark has the second, third or fourth rows of teeth, one would probably have to look under the predator’s skin. There are more than a hundred such teeth, and they are freely located under the skull. To expose the gums and teeth when biting, special grooves and muscles in the skull are activated. While the lower jaw rises to clamp the next victim, its flap increases. A massive blow from the upper jaw finishes what he started. Hunting in this way, a shark can eat more than 180 kilograms of meat. And this is just one time! Considering that catching prey is sometimes not so easy, the shark constantly improved its killing mechanisms. And she had enough time for this - more than a million years.

Organs of vision

Eyes are another mechanism created for hunting. But you have to do this in a poorly lit environment. However, the organs of vision are also the most vulnerable place that a great white shark has on its body. Photos taken by many amateurs and scientists confirm that the predator has to stick its head out of the water in order to better see the world around it. No other fish in the world is capable of this.

Shark eyes have a special reflective layer located behind the retina. This allows you to hunt even when there is not enough light. It is reflected in the eyes of the shark, and it is able to see its prey even in dark water. But eye sensitivity has its drawbacks. During an attack they are quite easy to damage. Probably, the shark would not have been able to survive for millions of years if nature had not taken care of this predator and given it an ideal means of protection. Just as the carcharodon is ready for its famous killing bite, its eyes roll inward.

Intelligence

To operate this killing machine, you need a truly developed intellect. After all, she must not only hunt successfully in order to survive, but also make long journeys. In order to decipher the signals from all senses (and the shark has six of them), the level of brain development must be at a fairly high level. In Carcharodon, the brain occupies the entire cranium. Like all other shark organs, it was formed over millions of years.

Reproduction

The white shark is an ovoviviparous fish. In fact, it is not known how the mating of individuals and the birth of cubs occurs, since no one has witnessed this. However, it is safe to say that the female carries the cubs for about 11 months. In addition, cannibalism is developed among these unborn babies. Scientists call it intrauterine. Nature has established that strong offspring destroy weak ones in the womb. The female may give birth to only one or two cubs, but you can be sure that they become the strongest among their brothers and sisters. Naturally, babies are born immediately with teeth. They also cover most of their body. Thus, the young survive in the harsh underwater world.

Menu

By nature, the white shark is very aggressive. She is capable of attacking any victim within reach. However, its main diet consists of fur seals, seals, bony fish and stingrays. In addition, the white shark, without a twinge of conscience, kills its relatives - sharks of other species that are inferior to it in body size.

The young begin to hunt immediately after birth. However, they are only capable of small fish, dolphins and turtles. Once a young shark reaches a size of three meters, it is able to cope with prey whose body size is two-thirds of its own.

Cases of attack on a person

It is worth saying that people are a minor and not the most favorite component of the great white shark’s menu. Cases where a shark attacks a person occur mainly due to the fault or negligence of the latter. Some enthusiasts forget that swimming up to a predator is deadly. Undoubtedly, there are cases when a shark attack is unprovoked. The reason for this may be severe hunger as a result of an unsuccessful previous hunt. Some populations of white sharks, for example the Mediterranean, are surprisingly friendly towards humans.

Security

The white shark is at the top of the food chain, so it has practically no natural enemies. The only exception is the large killer whale, and of course, humans. Today the shark is in a vulnerable position. Hollywood directors, without knowing it, did a disservice to the predator. After the release of the movie Jaws, it was the great white shark that was under threat. A photo of a predator is not the only trophy that adventurers want to get. Shark jaws are extremely popular and are sold at impressive prices on the black market.

Due to the fact that the population of this predator is declining every year, it has been taken under protection in many countries. Among them are Australia, USA, South Africa.