Fear and curiosity - these are the feelings the creators of the blockbuster “Jaws” hoped to evoke in viewers, but the effect exceeded all expectations. And we're not talking about Oscars and record box office receipts. The great white shark, presented in the film as a monster greedy for human flesh, began to be caught and exterminated without hesitation.

However, ichthyologists will say that in most cases, attacks by white sharks on humans are the result of incorrect identification of a swimming object. When viewed from the depths, a diver or surfer can easily pass for a pinniped or a turtle, and in general, great white sharks, due to their curiosity, try everything by the skin of their teeth.

Today, about 3.5 thousand individuals of this ancient predator live in the world's oceans, which is undoubtedly dangerous and therefore not well studied. But like any animal with a sinister reputation, the big White shark will always arouse interest, especially among thrill-seekers.

Origin of the white shark

It was previously believed that white sharks descended from megalodon - giant fish, up to 30 m long and weighing almost 50 tons, extinct 3 million years ago. But modern research The remains of the superpredator made it possible to establish that megalodons belong to the family Otodontidae, and white sharks belong to the family of herring sharks, so the number of supporters of this version has greatly decreased.

Today, scientists consider Isurus hastalis, one of the extinct species of mako shark, to be the recognized ancestor of the white shark. Both predators have almost the same tooth structure, only in the white shark, during evolution, serrations have formed along the edges of the teeth.

Taxonomy of the white shark

The white shark belongs to the class of cartilaginous fish (Chondrichthyes), which means that its skeleton does not have bones, but consists entirely of cartilaginous tissue. In addition to sharks, stingrays and chimeras have this feature.

The white shark is part of the order Lamniformes, which unites large species of sharks with a torpedo-shaped body.

The dense build, pointed snout and 5 gill slits made it possible to classify the white shark as a member of the family of herring or lamn sharks (Lamnidae). Its closest relatives are the mako shark, salmon shark and lamna.

The genus of white sharks (Carcharodon) includes 2 extinct and one modern species - the great white shark (Carcharodon carcharias), also called carcharodon or, due to its sad fame, the man-eating shark.

Appearance of a great white shark

This is a stocky fish with a dense body, elongated in the shape of a torpedo. The head of the predator is very large, conical, with a pointed muzzle and mouth, curved into a parabola. On the sides of the head, closer to the pectoral fin, there are 5 huge gill slits that provide water respiration.

The pectoral fins are large, elongated in the shape of a sickle. The first dorsal fin is high, triangular in shape, growing slightly further than the base of the pectoral fins. Sometimes its top is rounded. The second dorsal fin is very small, as is the anal fin. On the pelvic fin of males there is an elongated element - a copulatory outgrowth.

The tail fin blades of the white shark are of the same width, which is typical of other herring sharks, which are capable of developing decent speed before attacking.

The name “white” shark does not quite accurately convey the coloration of the predator. Her top part and the sides are often gray, sometimes brownish or with a blue tint. There are dark, almost black specimens. But the belly of a white shark is dirty white.

Newborn sharks and adult individuals are completely identical in appearance, but differ only in size.

How much does a white shark weigh?

The maximum possible size and weight of Carcharodon still causes heated debate in scientific circles. In the authoritative encyclopedia of past years, “Animal Life,” 1971, the greatest height of a measured white shark is called 11 m, without indicating weight. However, the opinion of modern scientists on this matter is less optimistic. Ichthyologists believe that, given an ideal habitat, a white shark can grow to a maximum of 6.8 m in length.

A number of scientific sources claim that the largest white shark was caught off the coast of Cuba in 1945. Its length was 6.4 m and its estimated weight was 3,324 kg. The measurements were based on a photo of a white shark, so some experts believe that the real size of the fish is overestimated by at least 1 meter.

In 1988, a white shark was caught off the Canadian coast, which was measured and weighed. It was a female, 6.1 m long with a body weight of about 1,900 kg. This specimen is considered so far the only one whose dimensions and weight have been reliably confirmed.

Interesting fact: if you compare the weight of a great white shark with major representatives other families, then its mass with the same length will be almost 2 times greater!

On average, adult individuals weigh from 680 to 1,100 kg. Females are heavier and larger than males, their length is 4.6-4.9 m, males grow from 3.4 to 4 m.

Nevertheless, what excites minds is not so much the impressive dimensions of the great white shark, but its deadly mouth. After all, larger predators live in the depths of the sea, for example, representatives of the family of giant sharks, and the teeth of the white shark are unique in their own way.

How many teeth does a white shark have?

This predator has the largest teeth of all fish existing today, their length is about 5 cm. Triangular-shaped teeth with rough jagged edges are arranged in several rows and are constantly renewed. The number of rows depends on the age of the fish, there are from 3 to 7. The upper jaws bear larger teeth, on the lower jaw the teeth are smaller but sharper.

Each row can contain from 30 to 40 teeth, i.e. total number There are more than 300 teeth in the mouth of a great white shark.

The teeth of the first, working row quickly wear out and, to replace the lost ones, fully formed new teeth rise from the gums and move forward. This “conveyor” is ensured by mobility in the gums and short tooth roots.

Today, thrill-seekers don't have to watch thrillers about sharks. An extreme type of ecotourism is extremely popular - cage diving, when a person, protected only by metal bars, sees the deadly jaws of the famous predator at arm's length. Entertainment costs everyone 50-150 euros. Dangerous rides await their customers in places largest accumulation representatives of the species.

Where are white sharks found?

Despite the obvious trend towards reduction in the species, white sharks continue to inhabit all oceans except the Arctic. The most numerous populations are found off the coast of South Africa, the American state of California, the Mexican state of Baja California, Australia and New Zealand. This is where they come from best photos white shark, chilling with its realism.

Most carcharodon prefer coastal waters of the temperate zone with temperatures from 12 to 24 ° C and stay almost below the surface of the water. However large specimens thrive in tropical waters, cold seas, the open ocean, and also at considerable depth. According to documented data, a great white shark was once caught at a depth of 1,280 m using industrial bottom tools.

Before the invention of radio beacons, it was believed that long journeys were characteristic only of male white sharks, while females stuck to their native shores all their lives. However, the ability to track the movements of fish using modern equipment has proven the fact of long migrations by individuals of both sexes.

For what purpose great white sharks travel enormous distances remains a mystery. For example, it took one individual 9 months to travel 20 thousand km from the coast of South Africa to Australia and back. Perhaps long migrations are associated with reproduction or seasonal fluctuations in the food supply in different parts of the range.

What do white sharks eat?

Their diet is extremely varied, but despite their reputation for eating everything, white sharks feed primarily on fish, crabs, small marine animals, cephalopods and bivalves. Among the fish found in the stomachs of caught specimens are herring, sardines, stingrays and tuna. Dolphins, porpoises, sea beavers, sea lions and seals are often the prey of predators.

Undigested remains in the stomachs of white sharks once again confirms how aggressive these predators are towards others sea ​​life. Their victims include beaked whales, sharp-snouted crocodiles, northern elephant seals, sunfish and different kinds sharks: dusky dogfish, Australian nurse shark, great blue shark, fox and dogfish. However, such a menu is not typical for most white sharks and is rather the exception.

White sharks will not refuse carrion and happily eat the carcasses of dead cetaceans. Various inedible objects are often found in the stomachs of predators, for example, pieces of plastic, wood and whole glass bottles.

Sometimes great white sharks practice uncharacteristic cannibalism. For example, in the waters of Australia, before the eyes of observers, a 6-meter white shark bit its 3-meter relative in half.

If the hunt is successful, predators eat for future use. Thanks to its slow metabolism, a white shark weighing about a ton only needs 30 kg of whale blubber for 1.5 months. However, these are purely theoretical calculations, and in practice, predators eat much more, while demonstrating hunting skills honed over millions of years of evolution.

White shark hunting methods

Carcharodons live and hunt alone, but sometimes exhibit social behavior. For example, in the coastal waters of Cape Town, a group of 2-6 individuals is regularly spotted, which behave quite peacefully in the flock.

Observations carried out in South African waters have proven that there are various kinds of hierarchies within such groups. Females dominate over males, large individuals over smaller ones. At the meeting, representatives different groups and loners quickly determine the social position of each other and the alpha leader. Conflicts are usually resolved with warning bites and in most cases end there. However, white sharks always separate before hunting.

Unlike their relatives, white sharks often stick their heads out of the water, catching odors wafting through the air. This usually happens when patrolling archipelagos, where pinnipeds set up rookeries.

When the animals are in the water, the white shark begins the hunt. It swims towards the victim just under the surface of the water and makes a sharp throw, sometimes jumping half or completely out of the water. Seals or fur seals are grabbed from below across the body, large individuals are dragged to the depths and drowned, then torn into pieces and eaten. Small ones are swallowed whole.

In fog and at dawn, the chances of a white shark attacking the first time are 50/50. If the attempt is unsuccessful, the predator pursues the prey, reaching speeds of up to 40 km/h.

Northern elephant seals, which are found in abundance off the coast of California, are bitten from behind by white sharks, immobilizing them. Then they wait patiently for the victim to bleed out and stop resisting.

Dolphins are never approached from the front, excluding the possibility of detecting danger using echolocation.

If you don't try, you won't know. According to this principle, great white sharks determine the edibility of any object, be it a buoy or a person. According to statistics, between 1990 and 2011 there were 139 white shark attacks on humans, of which only 29 were fatal.

Even after an attack, carcharodons do not intentionally pursue people; the victims are single swimmers who die from painful shock. When there is a partner, the wounded man can be saved by driving away the predator and leaving the danger zone together.

Only newly born sharks hunt on their own and do not pose a danger to humans or large animals.

Reproduction of white sharks

Reproductive maturity of white sharks occurs late, when the fish reach their maximum size. Females mature at the age of 33 years, males are ready to breed at 26 years.

These predators do not survive in captivity, so research on their mating behavior and reproduction contains very little information.

Great white sharks are ovoviviparous fish. This means that fertilized eggs remain in the mother's oviducts. They hatch into embryos that feed on the eggs produced by the ovaries. A pregnant female carries on average 5-10 embryos, but theoretically a litter can contain from 2 to 14 cubs. During the early and intermediate stages, the hatchlings' bellies are very distended and filled with yolk, and when egg production stops, the fetus digests the nutrient reserves.

The exact timing of gestation in white sharks is unknown, but scientists believe that pregnancy lasts more than 12 months. The baby sharks are born fully developed, 1.2 to 1.5 m long, and ready to live independently.

How long does a white shark live?

The average lifespan of a great white shark is estimated at 70 years. Studies based on the study of vertebral growth have made it possible to determine the age of the oldest white shark. It turned out to be a 73-year-old male. However, not everyone manages to live to an old age.

Previously, scientists believed that the predator at the head of the food chain did not have natural enemies. But at the end of the last century, reports appeared of attacks on white sharks by killer whales - even larger and more bloodthirsty predators.

Another enemy of the white shark is the saltwater crocodile, which can turn over big fish and easily rip out her throat or belly.

Water pollution, accidental capture and poaching also reduce the already low numbers of the species. The price of a tooth on the black market is $600-800, and the cost of great white shark jaws reaches $20-50 thousand.

Today, predators are protected by law in many countries, for example, Australia, South Africa, the American states of Florida and California. By the way, Peter Benchley, the author of the famous novel “Jaws,” clearly did not expect the negative consequences of the sensational film adaptation. Therefore, the writer devoted the last 10 years of his life to studying the ocean ecosystem and actively advocated for great white sharks.

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 dirty. White color. 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 opportunity 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, 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.

Totally agree last years 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 severe 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

Great white shark (lat. 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 oceans of the Earth, except the Arctic Ocean.

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 sea ​​predators: Mako shark (Isurus oxyrinchus), longfin mako shark (Longfin mako), Pacific salmon shark (Lamna ditropis) and 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. Maximum size The 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 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, requiring them to 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 the 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. Typically, 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 Embryonic development embryos develop slowly, but the hatched baby shark differs from the adult only in size and is capable of independent life.

More than 30 percent of all species are oviparous. famous sharks. 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 most modern species(more than half), the egg develops in the female’s body. 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 they total not great in the litter.

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 are appearance They even resemble the testes of males.

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 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. White sharks in the video are doing the usual daily life, hunting mainly 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. Great importance the salinity level of the water also affects it. 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 his dislike for cold water, in the Atlantic Ocean the predator was seen 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 a predator to blend in with 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 get a better look. the world. 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. To decipher the signals from all sense organs (and a shark has six of them), the level of brain development must be at a sufficiently high level. 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.

The second article in the series “Summer with Sharks” talks about the famous representative of giant sea predators - the great white shark, memorable to many based on the film"Jaws" Is this huge fish as dangerous and bloodthirsty as is commonly believed?

An encounter with a great white shark in the ocean is somehow not like what one imagines: the fish does not at all look like a bloodthirsty monster, which is talked about in thousands of television programs with chilling intonations in the voice. She is very plump - she looks like a fat sausage - with a mouth that seems to be slightly open in a smug grin, with quivering flabby jowls. In a word, if you look from the side, one of the most dangerous predators planet resembles a blue-eyed clown. And only when the “clown” turns to face you, so to speak, do you understand why this predator causes such fear - and they fear it almost more than any other animal on the planet. The shark's muzzle no longer seems flabby - it narrows into an ominous battering ram with black, unblinking eyes. The grin disappears, and all you see are rows of five-centimeter teeth protruding from the jaws (when biting, they create a force of 1800 kilograms per square centimeter). The shark is slowly but surely approaching you. Turns his head - first in one direction, then in the other, assessing whether the prey, that is, you, is worthy of spending time on it. Then, if you're lucky, she'll turn around, turning back into a clown, and lazily disappear into the underwater darkness. There are more than 500 species of sharks in the world's oceans, but in the minds of the vast majority of people there is only one. When Pixar needed a villain for the cartoon Finding Nemo, it chose neither a harmless nurse shark nor an aggressive one for the role. blunt-nosed shark, and not even brindle, which would look more appropriate on coral reef where Nemo lives. No, it was the great white shark that was grinning from thousands of posters around the world. This fish is a symbol of the World Ocean, but our knowledge about it is very meager - and much of what we seem to know is simply not true. White sharks are not killers blinded by bloodlust (on the contrary, they act carefully when attacking prey), they do not always live alone and are probably smarter than scientists until recently believed. Even the famous series of attacks off the coast of New Jersey in 1916, mentioned in the movie Jaws, may have been the work of a blunt-nosed shark rather than a great white shark. We don't know for sure how long she lives, how many months she bears her offspring, or when she reaches sexual maturity. No one has ever seen great white sharks mate. or produce offspring. We don’t really know how many there are and where they spend most of their lives. If a predator the size of a small truck lived on land in California, South Africa or Australia, experts would observe representatives of this species in zoos or research centers and study it in detail mating behavior, migration routes, habits. But underwater there are laws. White sharks appear and disappear at will, and following them into the depths of the sea is almost impossible. They do not want to live in aquariums - some refuse to eat and die of hunger, others attack all their neighbors and smash their heads against the walls. And yet scientists using modern technologies, may already be close to answering two of the most exciting questions: how many great white sharks are there and where they are hiding. This is necessary to know in order to decide how to protect ourselves from white sharks and how to protect them from us, and to understand what the most terrible predator on the planet deserves more - fear or pity.

Brian Skerry A large white shark tears open the surface of the water near the Neptune Islands. Scientists distinguish sharks by their dorsal fins, scars and a jagged line separating the white ventral and gray dorsal parts of the body.

A seven-meter fishing boat bobs on the waves off the southern tip of Cape Cod, Massachusetts. It's a beautiful summer day. The passengers - three scientists, two paying tourists, a couple of journalists and the captain - sat comfortably on the seats, looking towards the island of Nantucket. Suddenly the radio comes to life, and the voice of the observer pilot from a height of 300 meters reports in a sharp New England accent: “There is a great shark ! Marine biologist Greg Skomal perks up. He stands on a bridge fenced with railings, protruding one and a half meters ahead of the bow of the boat and similar to the board on which pirates pushed those sentenced to death into the sea. If we were in a Hollywood movie, Greg would have a wooden leg and be holding a harpoon. But instead of a harpoon, Greg holds a three-meter pole with a GoPro camera attached to the end. And he beams with joy when the captain starts the engine. Until 2004, virtually no one had seen great white sharks off the East Coast of the United States. From time to time, individual individuals appeared near the beaches or got caught in nets, but this happened very rarely. In general, white sharks gather at certain times of the year in five areas that scientists call “hubs,” similar to airport hubs. The three main hubs are located off the coast of California and Mexican Baja California, the southern coast of South Africa and Australia, where these predators hunt seals. However, the East Coast is not that place: there are not enough seals here. The sharks that swam here were homeless strays. In 2004, one female made her way into the bays near the village of Woods Hole, Massachusetts. For Skomal, who by that time had been successfully tagging other shark species with electronic beacons for twenty years, this was a rare chance: a great white came, one might say, right into his yard! “I thought it was an accident that would never happen again,” he says, a smile playing across his face, framed by tousled gray hair. Over the next two weeks, Skomal and his colleagues followed the shark, which they named Gretel, after the lost girl in the Brothers Grimm fairy tale, and eventually equipped it with a beacon. Scientists hoped to track the shark's movements in the Atlantic Ocean, but after 45 minutes Gretel's beacon fell off. “My excitement turned to deep despondency, because I was sure that I had missed a once-in-a-lifetime chance to learn something new about the great white shark,” Skomal recalls. Over the next few years, he thought a lot about Gretel and whether she really was a loner. But in September 2009, fortunately, everything became clear: five great white sharks were spotted from an airplane near the cape. Within a week, Skomal had tagged them all. “I almost went crazy with joy. My heart was beating so hard that it was ready to jump out of my chest. Everything I dreamed of has come true!” Greg says. Since then, great white sharks have returned here every summer. Some scientists have even called Cape Cod a sixth hub. How many sharks are there? To answer this question, let’s look at data from the California hub. The first attempt to count sharks here was in the mid-1980s by Scott Anderson, who at that time was studying seabirds on an island located west of the Golden Gate Bridge in San Francisco. Anderson and his colleagues tracked the sharks - first visually, then using acoustic beacons and finally using satellites. Over the past 30 years, they have processed data from thousands of observations of individual sharks, which were distinguished by the shape of their dorsal fins, markings on their skin or the characteristic border between their gray back and white belly. It is now known where these sharks gather and what they eat (most of the “observations” returned here from year to year). So, based on such observations, is it possible to determine the number of sharks? In 2011, a group of scientists tried to make such a calculation, and it turned out that only 219 adult sharks live in the Californian waters that are richest in sharks. Even taking into account that the number of predators at the top of the food pyramid is usually much smaller than the number of animals they hunt, this is still negligible. The results of the study stunned the public and were immediately criticized by other experts.

Brian Skerry Biologist Greg Skomal tries to take video of a shark swimming near Cape Cod. IN Lately great white sharks have begun to appear regularly in the waters off a popular beach.

Of course, counting the number of great white sharks is much more difficult than land animals or even marine mammals. Therefore, scientists draw conclusions based on their assumptions about the routes of movement of sharks. In the case of the California coast, the most important assumption was that data from a few feeding sites were generalized to the entire hub. Another group of scientists processed the same data, taking into account other assumptions, and their number of sharks turned out to be ten times larger (although they also counted juveniles). Soon, ichthyologists began counting sharks in other hubs. For example, the population size of South African sharks was estimated at 900 individuals. How big or small are these numbers? Are great white sharks thriving or going extinct? There are about 4 thousand tigers and 25 thousand African lions. Based on the lowest estimates, there are as many great white sharks on the planet as there are tigers, and they are known to be an endangered species. If we take the highest estimates, then these fish are no less numerous than lions - a vulnerable species. Some experts believe that sharks are dying out, while others, on the contrary, see positive changes. Some say that the increase in seal numbers indicates that there are almost no great white sharks left, while others argue that the more seals there are, the more sharks there must be. For example, Australian statistician Aaron McNeil believes that the appearance of sharks off the Cape Cod Peninsula and the increasing frequency of sightings of them in the Southern Hemisphere support an optimistic point of view. “Over the last decade, I don’t see any evidence that there are fewer sharks,” says McNeil. – There was a period of decline in numbers in the past, but today it cannot be said that great white sharks are becoming extinct. Their numbers may be very slow, but they are growing.” Hope remains. Nowadays, if anyone catches great white sharks on purpose, it is very few fishermen - but the Convention on International Trade in Endangered Species lists this species as the second most strictly protected category, since fishermen sometimes catch these fish unintentionally. After all, if the number of a species is small, even an accidental catch can deal a crushing blow to its populations - and the great white shark, being a top predator, plays a vital role in the ecology of the oceans. To understand whether great white sharks need our protection, it is necessary to know not only their numbers, but also where they wander. Their migration paths are not as orderly as, say, birds or butterflies. Some sharks follow along the coast, others tack hundreds of kilometers into the open sea. Many white sharks, depending on the time of year, change warm waters to cold ones and vice versa. And males, females and juveniles seem to follow different paths. Today, with long-term satellite beacons, scientists are finally beginning to understand these intricacies. We now know that adult white sharks in California and Mexico are moving offshore. late autumn and go deep into the middle of the Pacific Ocean. "It's not at all clear why they go to this area, which some call an ocean desert," says Salvador Jorgensen, a biologist who studies the migration and ecology of great white sharks. “What the hell did they forget there?” Is this the “shark center” where great white sharks mate in a way that no one has ever seen? The water area about which we're talking about, the size of California, and the depths there reach kilometers, and it is difficult to observe sharks. However, satellite data shows that females follow direct routes, while males surface and submerge, probably in search of mates.

This is how an idea of ​​the life of great white sharks of the California coast is gradually formed. After spending the summer and fall hunting seals, they head to the ocean depths to begin breeding. At this time they live off accumulated fat reserves. Then the males return to the coast, and the females swim off to who knows where for a year or so, perhaps to give birth to offspring. The cubs are later shown at feeding grounds (for example, off the coast of Southern California), where they eat fish before they grow large enough to join the older cubs. It's not a complete picture—males and females don't spend much time together, and we don't know where the babies are born—but it explains a lot. For example, as the population recovers, more young are born, which may be why there have been a lot of shark sightings in Southern California lately. In other places, calculations are more difficult to make. Australian sharks feed off the southern coast of the mainland, but they do not seem to have a "center" of their own. As for the Atlantic, our knowledge here is even poorer. “We have rogues and we have coastal sharks. And I have no idea what motivates both,” says Greg Skomal. On a clear August morning, I board a two-seater plane with Wayne Davis, a pilot who spent years tracking tuna and swordfish for fishermen and now helps scientists search for white sharks. It's so shallow here that sharks can be seen from the air. In just half an hour of flight we see seven - all of them patrol areas of the coast near which gray seals feed. On the way back, one and a half kilometers to the north, we fly over beaches crowded with vacationers. So far, local residents are welcoming to their new neighbors. Stores sell toy sharks, T-shirts and posters featuring them, even a new local mascot high school- great white shark. Sharks are usually depicted in profile – smiling, looking like clowns. But sooner or later, someone will encounter another version of the great white shark in these waters - the one with teeth. However, these predators make attempts on human life extremely rarely. In California, the likelihood of a surfer being bitten by a great white shark is one in 17 million, according to Stanford University, and even less for people just swimming in the water—one attack per 738 million vacationers. Will we be able to lend a helping hand to this toothy monster, are we ready to take pity on the ruthless monster?

A well-known representative of predatory fish is the great white shark. Individuals belonging to Carcharodon carcharias live in the surface layers of the water column of various oceans, although they are also encountered at depth. Only in the Arctic Ocean there are no sharks. These predator fish are called white death, man-eating fish and carcharodon (terrible-toothed).

Characteristics of the white shark: size, weight, teeth structure

White sharks owe their name to their specific appearance. The peritoneum of predatory fish, their sides and back are painted white. gray, in some individuals it is gray-blue or gray-brown.

Due to the specific color, it is difficult to notice fish from afar. The gray color of the back and sides makes it impossible to see them from above; they merge with the surface of the water. If you look up from the ocean floor, the white belly does not stand out against the sky. The shark's body is visually divided into 2 parts when viewed from the side from afar.

Female sharks are larger than males. The average length of female Carcharodon is 4.7 m, and males grow up to 3.7 m. With this length, their body weight varies between 0.7–1.1 tons. According to experts, man-eating fish found in ideal conditions, can grow up to 6.8 m. The body of the white shark is spindle-shaped and dense. There are 5 pairs of gill slits on the sides. The large conical head contains small eyes and nostrils.

Due to the grooves that approach the nostrils, the volume of water flowing to the olfactory receptors increases

The mouth of a predatory fish is wide and has the shape of an arc. Inside there are 5 rows of triangular sharp teeth, their height reaches 5 cm. The number of teeth is 280–300. In young individuals, the first row of teeth completely changes every 3 months, in adults - every 8 months. A special feature of Carcharodon is the presence of serrations on the surface of the teeth.

Powerful shark jaws can easily bite through cartilage and break the bones of victims they encounter. With the help of a study conducted in 2007, it was possible to find out the bite force of this predator.

Computed tomography of the shark's head helped establish that the bite force of a young specimen weighing 240 kg and 2.5 m long is 3131 N. And a shark 6.4 m long and weighing more than 3 tons can close its jaws with a force of 18216 N. According to some, According to scientists, information about the bite force of large sharks is overestimated. Due to the special structure of their teeth, sharks do not need to be able to bite with great force.

The first large fin on the back looks like a triangle, the pectoral fins are crescent-shaped, they are long and large. Anal and second dorsal fins small size. The body ends with a large tail, its plates are equal in size.

U large carcharodon circulatory system well developed. This allows predators to warm up their muscles and increase the speed of movement in the water. White sharks do not have a swim bladder. Because of this, carcharodons are forced to constantly move, otherwise they sink to the bottom.

Where does it live?

The habitat of man-eating sharks is huge. They are found both in coastal areas and further inland. Mostly sharks swim in surface waters, but some specimens could be found at a depth of more than 1 km. They prefer warm bodies of water; the optimal temperature for them is 12–24 °C. Desalinated and low-salt waters are not suitable for sharks.

Carcharodons are not found in the Black Sea

The main centers of concentration of predators include coastal zones in California, Australia, South Africa, and New Zealand. Sharks are also found:

• near the coasts of Argentina, the Republic of Cuba, the Bahamas, Brazil, and the east coast of the USA;
• in the east of the Atlantic Ocean (from South Africa to France);
• V Indian Ocean(found near the Seychelles, in the Red Sea and the waters of the Republic of Mauritius);
• V Pacific Ocean(along the west coast of America, from New Zealand to the Far Eastern territories).

Sharks can often be seen around archipelagos, shallows, and rocky headlands where pinnipeds live. Separate populations live in the Adriatic and Mediterranean seas. But their numbers in these reservoirs have decreased significantly in recent years, and they have practically disappeared.

Lifestyle

by people social structure Shark populations and the behavior of individual individuals have not been sufficiently studied. With the help of observations, it was possible to reveal that the attack tactics of predators depend on the type of prey chosen. This is facilitated by heat body, thanks to which the functioning of the brain is stimulated.

Their attacks are so swift that in pursuit of prey they can completely emerge from the water. At the same time, animals develop speeds above 40 km/h. A failed attack does not stop the pursuit of the victim. They can raise their heads above the water while searching for prey.

Interspecific competition occurs in places where sharks and cetaceans have a common food supply

Previously it was believed that natural enemies white sharks do not have them. But in 1997, whale watchers witnessed an attack on an adult white shark. She was attacked by a representative of the cetaceans - the killer whale. Similar attacks were recorded later.

Nutrition and digestive system

The diet of Carcharodon varies depending on the age and size of the animals. They feed on small animals:

• fish (tuna, stingrays, herring and small representatives of the shark family are popular);
• pinnipeds (fur seals, lions, and seals most often suffer);
• cephalopods;
• birds;
• representatives of cetaceans (porpoises, dolphins);
• sea ​​otters, turtles.

Carcharodons do not neglect carrion. A whale carcass can be a good catch.

Of particular interest to large individuals are seals, other marine animals, and small whales. With the help of fatty foods they manage to maintain energy balance, so they require high-calorie food.

But they rarely attack porpoises and dolphins. Although in the Mediterranean Sea the latter are an important component of the diet of sharks. They attack this type of prey mainly from below, from behind and from above, trying to avoid detection by echolocators.

Contrary to popular belief, humans are not of interest to sharks as food due to the insignificant amount of fat. Carcharodons can confuse a human with marine mammals, which is believed to be the main reason for the attack.

White sharks have a slow metabolism, so they can sometimes go long periods without food.

Predators can go without food for a long time. It is believed that 30 kg of whale oil is enough to satisfy the metabolic processes taking place in the body of a shark weighing more than 900 kg for 45 days.

In terms of the structure of their digestive organs, sharks are practically no different from other fish. But Carcharodon has a pronounced division of the digestive system into various sections and glands. It begins with the oral cavity, which smoothly passes into the pharynx. Behind it comes the esophagus and the V-shaped stomach. The folds inside the stomach are covered with a mucous membrane, from which digestive enzymes and juices necessary for processing ingested food are abundantly secreted.

There is a special section in the stomach into which excess food is sent. Food can be stored in it for up to 2 weeks. If necessary digestive system begins to use the available reserve to support the life of the predator.

What distinguishes sharks from other species of fish and animals is the ability to “turn out” their stomach through their mouth. Thanks to this ability, they can clean it of dirt and accumulated food debris.

From the stomach, food passes into the intestines. The existing spiral valve contributes to more efficient absorption. Thanks to its presence, the contact of food digested in the stomach with the intestinal mucous membranes increases.

The following also take an active part in the digestion process:

• gallbladder;
• pancreas;
• liver.

The pancreas is responsible for the production of hormones and pancreatic juice, intended for the breakdown of carbohydrates, fats, and proteins. Thanks to the work of the liver, toxins are neutralized, pathogenic microorganisms are destroyed, and fats from food are processed and absorbed.

Features of behavior

White sharks do not live in one place. They move along the coast, make transatlantic journeys, but return to their usual habitats. Due to migrations, it is possible for different shark populations to intersect, although they were previously thought to live in isolation. The reasons for Carcharodon migrations are still unknown. Researchers speculate that this is due to reproduction or the search for places rich in food.

During observations in the waters of South Africa, it was revealed that the dominant position is assigned to females. When hunting, predators are separated. Conflicts that arise are resolved through demonstrative behavior.

White sharks start a fight in exceptional cases

Their behavior during hunting is interesting. The entire process of catching a victim can be divided into stages:

1. Identification.
2. Determination of species.
3. Approaching an object.
4. Attack.
5. Eating.

They attack mainly in cases where the prey is near the surface of the water. They grab large specimens in the middle and pull them under water. There they can swallow prey whole.

Diseases

The threat to Carcharodon is the small copepod crustaceans. They settle in the gills, feed on the shark’s blood and the oxygen supplied to it. Gradually, the condition of the gill tissues deteriorates and the shark dies from suffocation.

Predators are distinguished by their well-functioning immune system, which can protect them from autoimmune, inflammatory and infectious diseases, but they often get cancer. We have now identified more than 20 types of tumors that threaten the lives of sharks.

Reproduction: how white sharks give birth

Young sharks are born adapted to live independently

White sharks are ovoviviparous fish. The eggs inside the mother's body hatch into fry. They come out already grown up. There is no connection with the mother's body. The species reproduces by placental ovoviviparity. There are 2–10 sharks in a litter. Most often, 5–10 newborns are born. Their length at birth is 1.3–1.5 m.

The source of nutrients for growing embryos are the eggs produced by the mother's body. Sharks in the womb have a distended abdomen, 1 m long, with a yolk inside. At later stages of development, the stomachs become empty. Observers most often encounter newborn sharks in calm waters. They are well developed.

How long does he live?

The lifespan of Carcharodon is on average 70 years. In this case, sexual maturity in females occurs at 33 years of age, in males - at 26 years of age. They stop growing from the moment they reach maturity.

Assault on a person

People are not of interest to sharks, although there have been many recorded cases of them attacking. The most common victims are divers and fishermen who get too close to the predator.

In the waters Mediterranean Sea a "shark phenomenon" has been observed, according to which carcharodons swam away after one bite. According to experts, sharks that are hungry can easily feed on humans.

Most often, when meeting sharks, people die from blood loss, drowning or painful shock. When attacking, predators injure their prey and wait for it to weaken.

Playing dead is the worst option when encountering a shark.

Solo divers can be partially eaten by a shark, but people who dive with partners can be saved. Often those people who actively resist are able to escape. Any blows can cause the predator to swim away. Experts advise, if possible, to hit the shark in the eyes, gills, and face.

It is important to constantly monitor the location of the predator; it may attack again. Sharks readily feed on carrion, so the sight of an unresisting victim will not stop them.

Sharks are a little-studied species of predatory fish. A decrease in their numbers affects the food chain, because they are part of the ecosystem of the world's oceans. Despite the fact that little is known about white sharks, researchers have been able to identify a number of interesting facts related to these animals:

• Females have thicker skin than males. This is due to the fact that during mating the male roughly holds his partner, biting her fins.
• Shark teeth are coated with fluoride, which prevents them from deteriorating. Enamel consists of a substance that is resistant to acid produced by bacteria.
• Sharks have well-developed: vision, smell, hearing, touch, taste and sensitivity to electromagnetic fields.
• Sensitive olfactory receptors enable the shark to detect the smell of a seal colony located at a distance of 3 km.
• When hunting in cold waters, carcharodons are able to raise their body temperature.

Due to industrial fishing, the number of white sharks is rapidly declining. According to experts, there are about 3.5 thousand of them left all over the world. If sharks begin to die out, this could lead to the disappearance of many marine plants.