Sharks are predatory fish, dangerous and aggressive inhabitants of the ocean, the oldest known animals. This is what is commonly believed, and millions of people believe in it, drawing knowledge about these unique creatures from Hollywood horror thrillers. Let's figure out what we know about these amazing creatures, which appeared much earlier than all the civilizations of the world and perfectly adapted to modern life. What is a shark? Is it a fish or a mammal?
Amazing fish
All scientific and encyclopedic publications claim that sharks are cartilaginous fish, i.e. they have absolutely no bone tissue, which strikingly distinguishes them from their modern counterparts in their habitat. Together with the absence of gill covers and the structural features of the scales, the cartilaginous ostyca indicates the primitive organization of the species, or rather its ancient origin: It is known that 400 million years ago these fish were already swimming in the world's oceans. Despite this, sharks are one of the most advanced species of predatory ocean fish. Having adapted to a constantly changing environment for a long time, they have adapted perfectly and now get along well with modern bony fish and marine mammals, not inferior to them either in speed, or in agility, or in hunting skills. The list of sharks includes more than 400 species, completely different: from the smallest deep-sea shark, barely growing to 17-20 cm, to the giant whale shark, a huge 20-meter multi-ton individual.
An important difference from bony fish is their methods of reproduction. Some species of sharks are viviparous, meaning they give birth to live young. Some lay eggs protected by a dense cornea. Not all the secrets of their life have been discovered: there are species whose secrets of reproduction of offspring are still sealed. That is why the question so often arises: “Is a shark a fish or a mammal?”
Features of the view
The cartilaginous skeleton and the absence of bones are the main signs of the relationship of these fish to a group of animals of a primitive organization. But, as mentioned above, this in no way prevents the shark from living in almost all the oceans of the planet, having long ago gained fame as the most dangerous and aggressive predator. In addition, nature took care of the protection of this amazing animal. It's hard to find anything more protective than the scales a shark has. Located from head to tail, it feels like a satin coating to the touch, but you should not run your hand in the opposite direction - from tail to head: the sharp teeth will dig into the skin. Coarse sandpaper is a weak substitute compared to this perfect protection.
Let's look at the structure of the scales. Each scale of cartilaginous fish is equipped with a small spine with a point directed backwards. The top of the spike is covered with a layer of the strongest enamel, and its expanding base is fused with the skin of the fish. In the cavity of this outgrowth there are blood vessels and nerve branches. The size of the scales across the body of the fish is different: the largest is located on the head; the spines in the shark’s mouth, having transformed somewhat, ceased to be protection skin and turned into a sharp and extremely dangerous weapon of attack - magnificent teeth.
Main weapon
Being modified scales, shark teeth are arranged in a strict checkerboard pattern, in several rows. Throughout the life of a predator, teeth grow constantly, and when one row is worn down, new ones grow, located in the depths of the mouth. The shark's teeth are not used to chew food. She doesn't know how to do this. Their main purpose is to hold prey, tear it apart in order to swallow it without interference. U different types sharks different shape teeth, which is dictated by lifestyle features. Bottom-dwelling animals that feed on hard-shelled crustaceans have flat teeth with a ribbed surface that can crush calcareous protection. Predator fish have long sharp teeth to grab moving prey, or wide with a serrated edge, designed for tearing the flesh of large prey. Planktonic sharks have practically no need for teeth; in these species they are small, barely reaching 3-5 mm.
Another feature of cartilaginous fish is the absence of gill covers. Their role is played by 5-7 gill slits located behind the head, the number of which is determined by the type of shark, and the presence is a distinctive feature. However, like all fish, these predators, receiving oxygen from water, pass it through their gills. Availability respiratory system, characteristic of waterfowl, gives a comprehensive answer to the question: “Is a shark a fish or a mammal?”
Amazing abilities: smell, electroreceptor apparatus and lateral line system
It is impossible to overestimate the olfactory capabilities of sharks. It is one of the most advanced primary sensory systems. Experiments showed not just a high sensitivity of fish to odors, but a truly amazing one. The shark can smell blood diluted in water in a ratio of 1:1000000, and constantly uses its sense of smell when searching for prey or breeding partners during the mating season. In determining the location of an object, probably, in addition to the highly developed sense of smell, other organs and systems are also involved: hearing, as well as the lateral line located on the surface of the fish’s body, capable of sensing both insignificantly weak mechanical movements and the slightest in water, and playing important role when hunting, communicating with fellow humans and orienteering.
There are still unproven scientific assumptions about the ability of these predators to capture odors spread through the air, which prompted researchers strange behavior white shark. She often raises her muzzle above the surface of the water surface, as if sniffing.
The unique ability of sharks to detect prey by the movements of the respiratory and cardiac muscles and electrical fields with negligible voltage created by it has been scientifically proven. Long-term observation of the migration of some species over fairly long distances in a straight line made it possible to identify the possibilities of their orientation along magnetic field Earth.
Vision
The uniqueness of this representative of the fauna is once again emphasized by the special structure of the eye, which provides both protection from external stimuli and excellent visual acuity. Features of the structure of the shark's organ of vision include the presence of a blinking eyelid, which closes the eye at the moment of attack on the victim, thereby protecting it from damage. To be fair, it should be noted that not all species have eyelids. These individuals roll their eyes when attacking a victim.
Moreover, the shark's eye has a special reflective layer located behind the retina, which enhances the sensitivity of this organ and significantly increases visual acuity even in low light. Today, the fact that the vision of some species of these fish no longer requires proof is many times greater than that of humans.
Shark breeding
Unlike most bony fish, which produce millions of eggs, shark reproduction is more about quality than quantity. Characteristics cartilaginous fish - internal fertilization, common ovoviviparity and viviparity very significantly reduce the mortality of offspring, allowing for a high survival rate and lower fertility.
Depending on the species, sharks can be oviparous, viviparous, or ovoviviparous. Almost a third of all species are oviparous. After internal fertilization, the female lays eggs covered with a protein jelly-like layer, protected on top of it by a hard shell that protects the contents from dehydration and external damage. The supply of nutrients in the egg is colossal; it does not dry out during the full development of the embryo, which, it should be noted, is quite long. As a rule, a small number of eggs are laid at the same time: from 1 to 12. The only exception is the polar shark, which lays up to 500 eggs up to 8 cm long. The slow development of the embryo pays off handsomely - the hatched small shark is perfectly adapted to life and differs from adult only in size.
Distinctive feature Ovoviviparity is that, having hatched from fertilized eggs, the cubs remain in the mother’s oviduct for some time, being born developed and perfectly adapted to independent existence. Information about the timing of gestation in ovoviviparous species requires clarification. According to some reports, this period ranges from several months to two years, like that of a spiny shark, which is a record among all vertebrates.
In the womb of viviparous individuals, up to 30-80 embryos can develop simultaneously. Regardless of the type of shark and the method of reproduction, all are distinguished by the reproduction of a small number of offspring, but capable of independent life.
Planktonic sharks
For the most part, these fish are distributed in the oceans and seas, living in the water column from the surface to two kilometers deep, and are classified as true predators. But there are exceptions in this family: largemouth, giant, whale and some other species of sharks are filter feeders, feeding on plankton, small fish and squid.
Whale and basking sharks are considered the largest, reaching a length of 20 and 15 meters, respectively. Being planktonic fish, they slowly move, with their mouths open, in the center of plankton accumulations, driving water through gill openings with special outgrowths-plates, filtering a huge volume of water and extracting from it all living organisms larger than 2 mm.
There is very little information about the reproduction of planktonic species. So, the life of a giant shark is still completely unknown. Whale is oviparous. The eggs it lays reach very impressive sizes: the length can be 0.7 m, width - 0.4 m. Despite huge size, a planktonic shark fish, the photo of which is presented in this article, is not at all aggressive and is very slow.
The world of sharks is amazing and diverse. Some of them lead a bottom-dwelling lifestyle and feed on crustaceans and invertebrates, such as small cats, no more than 1 meter in length. The fishing object is spiny shark-katran, a photo of which is also presented in the article.
Fishing Katran
Katran, having a wide distribution, is the only kind, living in the Black Sea. This sea shark extremely cold-loving and does not favor warm waters. Perhaps this explains the fact that Black Sea katran rarely reaches 1 meter in length, although in the North Sea the size of this fish is 1.5-2 m. Spiny sharks practically do not rise to the surface of the water and do not approach the shore. They live at sufficient depth, gathering in large schools. Katranas feed on benthic invertebrates and bottom fish- flounder, whiting, and successfully hunt schools of anchovy.
It is amazing that the katran is an ovoviviparous fish, whose pregnancy lasts an incredibly long time - up to 2 years. The baby sharks will be born absolutely ready for the adult life of a predator. Inaccessible to humans, protected and cautious, they grow to adulthood without any problems. These sharks are safe for humans in the sea. They never swim close to swimmers. An incredible system of highly developed sense of smell and sensation of the slightest frequency fluctuations helps the katran to avoid meeting people.
Schools of this fish are approaching the shores late autumn. Then the fishing season begins. The second name for sharks - prickly - was given to katrans for a reason. This fish can cause a lot of trouble when it is taken out of the trawl. It has not only strong scales, but also sharp spines in front dorsal fins, at the base of which there are poisonous glands. When you come into contact with them, you can get a dose of poison, which, although not fatal, does cause some inconvenience. The Atlantic Ocean is the most generous with catches of katran: sometimes it is possible to catch up to 20 thousand fish in one catch.
Spiny shark - not just delicious fish, she is very gentle and certainly useful. In the skillful hands of a good cook, katran meat turns into magnificent delicacies, healthy and delicious dishes. An immutable rule when preparing shark meat is to drain the blood immediately after the fish is caught. It contains a high concentration of ammonia. If you do not get rid of the blood, the product will be hopelessly spoiled. The advantage of such dishes is the fact that there are no bones in their meat, because this fish is cartilaginous.
The skin of katrans is also valued. The abrasive properties of katran skin have always been used by craftsmen of many industries: from carpenters, cabinetmakers and joiners to furriers.
Tiger shark
Fully justifying its reputation as the thunderstorm of the tropical seas, Tiger shark, inferior to white in the number of recorded attacks on people, significantly exceeds it in percentage deaths after meeting her. The name of a shark is determined by its external features. The tiger shark (or sea tiger) is so named because of the dark transverse stripes on the gray, brownish-gray or greenish background of the body, which fade over time. Preferring shallow water, these sharks rarely go below 300 meters; cold waters do not attract them at all. The outstanding size of the fish - 7-8 meters in length and weight about a ton - puts it among the most large species. Streamlined body shape with big head, a blunt snout and 5 gill slits, as well as a large mouth with jaws equipped with 280-300 flat, scraper-like serrated teeth, and a well-developed upper lobe of the caudal fin - this is an incomplete portrait of this dangerous fish.
Sea tigers are attached to their favorite places; they do not like to leave the confines of their own residence. Being solitary predators, tiger sharks sometimes form groups if there is enough food. But most often they patrol their area alone.
The diet of these predators consists of dolphins, fish, and even small representatives of their own species. They are so omnivorous that the contents of their stomachs, representing a collection of objects far from organic food, surprise researchers. For their exorbitant omnivorousness, tiger sharks received the stigma of “sea scavengers.” But what is more than relevant for them is the ability to turn their stomach out through their mouth to rinse in water, which allows them to get rid of completely indigestible objects, such as cans, bags, and various garbage.
This dangerous shark is ovoviviparous, bearing its offspring for 14-16 months and giving birth to a litter of up to 80 sharks, each up to half a meter in size.
Great white shark
An exceptionally large aggressive predator - White shark or carcharodon, which has long and firmly held the sad championship in the number of attacks on people, is found in surface waters all oceans of the Earth, except the Arctic, preferring temperate and warm climate. It is not found in cold waters, and also does not live in slightly salted or desalinated seas. For example, carcharodon does not appear in the Black Sea. The most likely encounters with great white sharks are on the California coast, near the Mexican island of Guadalupe, in the Mediterranean and Adriatic seas, off the coast of New Zealand, where they can swim in small schools. The waters of the seas, where seals are found in abundance, are especially loved by these predators. For a long time there was an opinion about the permanent coastal existence of white sharks, but it has been proven that the fish migrates from the coast of California to African latitudes, swimming more than 20 thousand km per year.
Being the largest modern predator (some specimens reach a length of more than 10 meters with a body weight of up to 3.5 tons), the white shark does not give the victim any chance of salvation. This species owes its name to the color of the abdominal part - light or off-white. Its dorsal part is of darker tones: gray, greenish. Like all types of sharks, the white one does not have an air bladder, which explains the constant movement of the fish.
She is more partial to food than her tiger sister. The small shark feeds on small fish and mammals. Grown-up carcharodons hunt seals, dolphins, and smaller representatives of the species. Adults do not shy away from young or sick whales, often performing extraordinary tactical moves when attacking, which only confirms their intellectual abilities. This dangerous shark has long proven that it can handle any prey.
Little information is available about reproduction. Like many species, they are ovoviviparous with a gestation period of 11 months, at the end of which 1-2 cubs adapted to independent life appear. Today, the white shark population is rapidly declining; there are no more than 3,500 worldwide. The species is listed in the Red Book.
Sharks in the ocean are a fascinating and frightening sight at the same time. It can both delight and shock. Anyone who has seen not only photos of large sharks, but also a flock of white hunters with their own eyes will never forget this. After all, even paintings with images of predatory fish excite the imagination. The world of sharks is amazing, fantastic and dangerous. Ancient creature and a modern fierce predator coexist in a unique animal, attracting attention, again and again raising the question: “Is a shark a fish or a mammal?”
Currently, more than 450 species of sharks are known: from the deep-sea shallow Etmopterus perryi, only 17 cm long, to the whale shark, whose length reaches 12 meters.
Sharks are widespread in all seas and oceans, from the surface to depths of more than 2000 meters. They mainly live in sea water, but some species can also live in fresh water.
Most sharks are what are called true predators, but individual species, in particular whale, basking and largemouth sharks, are filter feeders; they feed on plankton, squid and small fish.
Skeleton
The skeleton of a shark is noticeably different from the skeleton of bony fish - it has no bones, and is formed entirely from cartilaginous tissue. Leather
Sharks are covered with placoid scales, the scales of which are rhombic plates ending in a spine protruding outward from the skin. In structure and strength, the scales are close to bones, which gives reason to call them dermal denticles. These teeth have a wide base, a flattened shape and a very relief-defined crown. In most cases, the crowns are very sharp and fit tightly together, so the skin may appear relatively smooth if you run your hand from head to tail, and vice versa - rough, like sandpaper, if you move in the opposite direction. Teeth and jaws
The teeth of most sharks are shaped like sharp dentin cones and sit on the cartilage of the upper and lower jaws. Teeth are regularly replaced as they fall out or wear out according to a conveyor belt principle - their replacement constantly increases with inside. In their structure and origin, these are modified placoid scales. Depending on their diet and lifestyle, teeth and jaws vary greatly between shark species. Benthic sharks, whose food is usually protected by a hard shell, have hundreds of small, smooth teeth. Pelagic species are characterized by the presence of very sharp teeth, adapted for easy penetration into the flesh of prey. Sharks such as tiger sharks have knife-shaped teeth designed for tearing the flesh of large prey. Plankton-eating sharks have vestigial small teeth.
Buoyancy
Unlike bony fish, sharks do not have a swim bladder. Instead, a huge liver, cartilaginous skeleton and fins help them compensate for negative buoyancy. Most species of sharks need to constantly move in order to maintain their breathing, so they cannot sleep for long periods of time. However, some species, such as the whiskered nurse shark, are able to pump water through their gills, allowing them to rest on the bottom.
Digestive system
After a hearty meal, sharks are able to for a long time starve, slowly and economically spending accumulated resources, and in general their need for food is relatively small. For example, a three-meter Australian sand shark weighing 150 kg kept in captivity ate only 80-90 kg of fish per year. Sharks periodically perform stomach eversion - they turn it out through the mouth into the aquatic environment for the purpose of cleansing. It is curious that they never damage the stomach with their numerous teeth.
Smell
Do sharks have a sense of smell? one of the main sensory systems. Experiments have shown the high sensitivity of sharks to odors. Are the olfactory organs represented by the nostrils? small bags on the muzzle that allow water to reach the olfactory receptors. The sense of smell is involved in searching for prey and breeding partners. The white shark uses 14% of its brain for smell. Do hammerhead sharks have a particularly well-developed sense of smell? The uniquely shaped nostrils, spaced at a decent distance from each other on the head, make it possible to more clearly determine the direction of the source of the smell. Research has shown that sharks respond better to the odors of wounded or alarmed prey.
Sharks can smell blood diluted 1:1,000,000, roughly equivalent to one teaspoon in a medium-sized swimming pool.
Vision
The structure of a shark's eye is for the most part the same as that of all vertebrates, but with some peculiarities. Does a shark's eye have a special reflective layer? tapetum? located behind the retina. The tapetum directs the light that passes through the retina back so that it once again affects the receptors, thereby increasing the sensitivity of the eye. This significantly improves visual acuity, especially in low light conditions. Another feature of some species is the presence of a blinking eyelid, which closes the eye directly during an attack on the victim, protecting it from damage. Sharks, which do not have a blinking eyelid, roll their eyes when attacking a victim.
Previously, it was believed that the shark's eye contains too few cones and is not able to distinguish colors and small details. However modern technologies made it possible to prove the opposite. The visual acuity of some shark species is up to 10 times sharper than humans.
Hearing
Sharks have a hearing organ? This is the inner ear, enclosed in a cartilaginous capsule. Sharks perceive predominantly low sounds of 100–2500 Hz. Most sharks are able to detect infrasound with frequencies below 20 Hz. The inner ear is also an organ of balance. Electro- and magnetoreception
Are the electroreceptive apparatus of sharks represented by ampullae of Lorenzini? These are small connective tissue capsules immersed in the skin with tubes emanating from them that open to the surface of the skin. Sharks respond to electric fields as low as 0.01 µV/cm. Therefore, they are able to detect prey by electrical fields created by the work of the respiratory muscles and heart.
Lifespan
Each species has a specific lifespan, and it is not easy to estimate it for all sharks. In general, sharks grow relatively slowly, and in general it can be said that most species live 20–30 years. However, the spotted spiny shark has a record life expectancy, living for more than 100 years. Whale sharks of a similar age are also known.
Reproduction
Sharks have a characteristic cartilaginous fish internal fertilization, a primitive uterus and a fairly perfect placental connection. The fetus develops in the uterus and is born well adapted to independent life. Newborn sharks have well developed musculoskeletal system, digestive system and sensory organs, which allows you to feed yourself and quickly gain weight. Sharks give birth different quantities cubs? some species up to 100, others only two or three. A white shark gives birth to approximately 3–14 pups at a time.
Unlike most bony fish, which produce millions of eggs, shark procreation focuses on quality rather than quantity.
The care of some species for their offspring (the baby shark is under the care of the mother for some time) allows sharks to have a high survival rate, and therefore lower fertility.
Lifestyle
In the traditional view, the shark looks like a lone hunter, roaming the ocean in search of prey. However, this description applies only to a few species. Many sharks lead sedentary, inactive lives. Contrary to the popular belief that the shark is just a “hunting machine” driven only by instincts, recent research has shown the ability of some species to solve problems, social behavior and curiosity. In 1987, off South Africa, a group of seven great white sharks worked together to pull down a half-stranded man. shore of the dead whale to a deeper place for a meal.
The ratio of brain to body mass in sharks is roughly equivalent to that of birds and mammals.
Sharks generally move at a cruising speed of approximately 8 km/h, but when hunting or attacking, the average shark accelerates to 19 km/h. The mako shark can accelerate to speeds of 50 km/h. The white shark is also capable of similar jerks. Such exceptions are possible due to the warm-blooded nature of these species.
Nutrition
The food preferences of sharks are very diverse, and they depend on the characteristics of each species, as well as on their habitat. The main food for sharks are fish, mammals, plankton and crustaceans. For example, lamna, mako and blue shark feed mainly sea fish pelagic species, and the shape of their thin, sharp teeth is adapted to grab prey in motion.
The white shark prefers seals and sea lions, but if possible, it also hunts whale mammals, since the characteristics of its teeth allow it to snatch off large pieces of flesh.
The diet of benthic sharks consists mainly of crabs and other crustaceans, and their teeth are short and adapted to breaking shells.
Basking, largemouth and whale sharks feed on plankton and small fish. marine organisms. Most species are carnivores.
Some species, such as the tiger shark, are almost omnivorous and swallow almost anything that comes their way.
After all, for the most part these are large and aggressive fish, which, while fishing with bait, are in a state of hunting for prey? that is, in increased excitement.
In addition, when removed from the water, some species may simply crush their internal organs its own weight, and this must be taken into account when moving a shark from the ocean to an artificial tank.
Further difficulties arise upon the arrival of sharks in the aquarium, which must have the necessary capacity for the normal life of these fish, and also take into account their increased sensitivity to electromagnetic waves.
Fishing and hunting
Along with other fish, sharks have been the subject of fishing for many years (more than 100 species). The fishing industry is interested in sharks:
Meat used as food by many cultures (although observations have shown that sharks are predisposed to accumulate mercury, the content of which in meat has increased significantly due to environmental pollution).
Fins, which in Asia are the main ingredient for a delicious soup, are also used in oriental medicine.
Cartilage, around which there is still controversy about its medicinal properties against cancer tumors.
Liver contains fat rich in vitamin A and B vitamins, and is used as a raw material for the manufacture of medicines.
Leather that is used in haberdashery and as an abrasive material.
The main fishery is carried out in Atlantic Ocean, where 26 species are commercially exploited, approximately a third of sharks are caught in Indian Ocean, and another one and a half times fewer sharks caught in the Pacific. Every year, approximately 100 million sharks are caught worldwide.
Shark fishing can be divided into three areas:
Fishing for the purpose of using their meat, liver, cartilage, skin and fins? that is, the full use of fish.
So-called bycatch? when the shark is incidental prey when catching other fish.
Fishing for the purpose of obtaining fins only. This is the most irrational (the weight of fins is up to 4% of the entire body) and inhumane method of catching sharks, which has received English language name Finnish? when the only target is the fins, and the rest of the carcass is thrown out to rot on the shore or back into the sea.
In addition to fishing for industrial purposes, there are also reasons for hunting sharks in the world such as ensuring the safety of beaches, reducing natural threats industrial types fish and just extreme hunting and fishing.
Common Misconceptions About Sharks
A shark must constantly swim to stay alive. In fact, many species are able to rest by lying on the bottom and pumping water through their gills. Most sharks attack and kill humans. Only a few species of sharks regularly commit unprovoked attacks on humans, and this is mostly due to misidentification of prey.
Sharks swim at high speed. In fact, sharks' cruising speed is quite slow, as they need to conserve energy. However, this does not prevent them from developing a high, so-called “throwing” speed immediately before attacking the victim.
Sharks love it human blood. Sharks do not have a preference for any blood. On the contrary, having grabbed a piece of flesh from a person, they usually spit it back, because this meat is not the high-fat food that they need to replenish their energy reserves.
Sharks are omnivores. Most species prefer to wait until they can get their regular food instead of eating everything.
Sharks are not susceptible to cancer. This belief, which existed for a long time, caused the death of a huge number of sharks caught by humans for the sake of “anti-cancer” cartilage. However, observing sharks in captivity, as well as in natural environment habitats showed the presence of individuals with organs affected by cancerous tumors. The number of cancer cases turned out to be higher where the water is more polluted (including from human activity).
Most of them are carnivores, but only a few species are considered serious predators that pose a danger to humans. One such species is the tiger shark. What does this fish look like? Where does she live? We will talk about its features in the article.
Tiger shark: photo, description of appearance
Because of the transverse stripes on their backs, they are called “sea tigers.” But this coloring is present on the body of predators only at a young age. Growing up to two meters long, they lose their bright distinctive features and become ordinary gray sharks with pale yellow bellies.
The appearance of these creatures is quite typical. Their body has a torpedo-shaped shape that tapers towards the tail. The snout of tiger sharks is slightly square, short and blunt. They have a large head with large eyes, behind which are squirts (gill openings through which water is sucked in and directed to the gills). They have a large mouth with many teeth with beveled tops and jagged edges. They work like blades that cut through the body of the prey.
In terms of size, tiger sharks are one of the largest representatives of their class. Adults reach an average of 3-4 meters in length. They weigh approximately 400-600 kilograms. Nai big shark This species reached 5.5 meters and weighed one and a half tons.
Habitats
Tiger sharks are thermophilic. They prefer shallow depths, as well as warm sea currents, which they follow during the cold season. Their range covers the seas of the tropical and subtropical zone.
Sharks live off the eastern and western coasts of Australia and America, in the seas of South and South-East Asia, in all the seas East Africa and off the western coast of the Sahara. They were found at depths of up to 1000 meters, but most often the fish are found at the surface (up to 300 meters) of the ocean or in shallow water. They often come close to the coasts, swim into river estuaries and marinas.
Predator or trash can?
By nature, tiger sharks are predators, but they can eat anything. The focus of their attention, as a rule, is on mollusks, crustaceans, turtles, small and medium-sized fish, small sharks, various pinnipeds and whales. They can even attack birds sitting on the surface of the water.
An interesting feature of this species is its unpretentiousness in food. They can catch other tiger sharks, pick up carrion from the seabed, and also eat things that seem not intended for this. Clothes, license plates, product packaging, bottles and cans are often found in the stomachs of caught sharks. Sometimes they contain the remains of non-swimming animals that most likely ended up unluckily near water.
Their acute sense of smell allows them to detect even a small amount of blood so that they can immediately go towards their “dinner”. They rarely attack right away. At first, they circle around the object that interests them, trying to somehow identify it. They gradually narrow the circle, and then rush at the victim. If the prey is medium in size, then the predator swallows it without chewing.
Lifestyle
Among the entire family of carchariformes, only tiger sharks are ovoviviparous. The eggs hatch into the young inside the mother's body and come out when they grow up. So, they are born as independent individuals, and after about five years they become sexually mature.
Pregnancy lasts up to 16 months, so females form packs to protect themselves from possible enemies. At other times, tiger sharks live alone and rarely form groups. Swimming in search of prey, they look huge and clumsy. But this is a misleading impression. Having identified a victim, they reach speeds of up to 20 km/h, easily maneuver and even jump out of the water when necessary. They live approximately 40-50 years.
Is it dangerous for humans?
One of the common fears in the ocean is the fear of encountering a shark. And it is quite justified, because this is one of the largest sea predators, “equipped” with powerful jaws and sharp teeth. The tiger shark is dangerous for humans because it often swims close to the shallows. In addition, she is not too picky about food and, being too hungry, eats literally everything. Among all shark species, the tiger ranks second in the number of attacks on people.
However, the image of aggressive and murderous predators has been greatly exaggerated due to the horrifying accounts of their victims, as well as popular culture. According to statistics, the chances of dying from their bite are not that high. Thus, approximately 3-4 people die from tiger sharks per year. Bees and ants turn out to be much more dangerous - they claim the lives of about 30-40 people per year. It is fair to say that there are no cases of shark attacks fatal outcome a lot more. Very often they only injure people by gnawing off individual pieces of meat or body parts.
One way or another, people are not their main goal. They can bite if you find yourself on their territory or if you start to provoke them in some way by excessively waving your limbs. They rarely attack calmly swimming divers, but they attack swimmers and surfers floundering in the water more often, confusing them with a feeding seal or turtle. Other possible reasons- hunger, aggressiveness during the mating season, the smell of blood, as well as simple curiosity. Sometimes their teeth serve as hands, and with the help of a bite they try to find out what is in front of them.
Sharks are the almost undisputed queens of the seas and oceans. There are more than 450 species of them - from small to great. The smallest of them reaches a length of only 17 cm. Majority much larger. Some are very big. They were included in the presented top 10 largest sharks.
By the way, it would be a mistake to consider the toothy inhabitants World ocean exclusively by predators. Among them there are also quite peaceful creatures that pose no danger to living beings. By the way, some of the species live in freshwater bodies. The largest shark in the world, of course, will not be found in fresh water, but quite large specimens can be found far from the seas.
This is not only one of the largest, but also one of the most aggressive sharks. They show their character already in the mother’s womb - embryos actively fight for the right to live. Natural selection does its job, and the most dangerous individuals are born.
The length of the mako is up to 3.5 m. The largest specimen surprised fishermen with its size of 4.5 m. Like the famous white shark, the mako can be dangerous to humans. This one is even related to the white one appearance. But in most cases, attacks on people are caused by the latter’s intrusion into the “sphere of influence” of the mako. Although there are also troubles caused by the excessive aggression of the white-like species.
Among other things, makos are very agile and fast. The maximum speed of movement of a large shark is 70 km/h. An aerodynamic aquatic inhabitant from the herring family is capable of jumping out of the water to a height of up to six meters.
The maximum officially confirmed length is 5.4 m. This makes the sixgill a participant in this rating. But the size of ordinary representatives of the species is more modest - within 3-4 meters.
It poses no danger to humans. But he doesn’t like being touched by divers and can’t even stand it. In such situations, it simply rushes to the depths. But it can rush – its capabilities allow a shark with six gills to descend to a depth of up to 2.5 km.
Usually one of largest sharks are quite slow and clumsy. But when attacking, she transforms - she becomes sharp and fast.
Further - largemouth shark, reminiscent of the “face” of space pirates without disguise from the children's series “Guest from the Future.” These beauties (sharks, I mean) are poorly studied, and they were discovered relatively recently - in the seventies. To date, only 60 deep-sea largemouths have been discovered. The largest shark among them reaches a length of 5.7 m.
To the rating sea fox got in thanks to its huge tail fin. Together with him, the predator reaches a length of about 6 m. But, since you cannot throw the tail out of the body, the cunning representative of sharks reasonably occupies a high position.
Despite its predatory nature, this species is not dangerous to humans. The king of nature causes fear in the fox shark, and the “tailed” cartilaginous fish attacks only its smaller marine colleagues.
The shark's long tail is used as a whip. They use it to stun prey. In English they have a special, additional name - thresher shark.
Huge The sea fox is capable of jumping completely out of the water. These are fast and powerful predators.
This shark is impressive not so much in size as in “design”. The hammer-shaped snout does not make the fish a beauty, but it definitely elevates it to the rank of the most original sea creatures.
The average dimensions of the “hammers” are 3 meters. But the maximum length, which is officially recorded, is 6.1 m. This is potentially aggressive and dangerous fish, and it’s better to stay away from her. But statistics say that hammerhead sharks are rarely interested in people. It is up to the divers to decide who to trust – statistics or probability.
Photos of the largest sharks must include images tiger species. The average size of sea tigresses is 5 m. There is every reason to believe that the oceans are full of tiger sharks measuring at least 7 meters.
Gigantic the tigress must be feared - it is not only very big, but also quite aggressive shark. Human remains are often found in the stomachs of these fish. In some countries, there are so many tiger sharks that they are shot to ensure the safety of people.
Most known species, anyone normal person causing, to say the least, mixed emotions. The man-eating shark is known for its aggressiveness, powerful jaws And a huge amount human casualties. White shark - greatest actress who appeared in films huge number once.
The largest white shark(of those that were caught) was 7.9 m long. There is information that larger specimens roam the oceans - up to 12-13 m. But the average size predators is 4-5 m. Average weight– 0.6-1.2 t.
Despite its popularity and reputation, this species is considered endangered - according to ichthyologists, there are about 3.5 thousand killer carcharodons left in the world.
This huge this pretty girl with a model look is one of the largest and slowest sharks. Regular size polar shark– 6-7 m. But the speed let us down – the northern species moves no faster than 2.5 km/h. Even for a one and a half ton fish, this is very little, but these are the conditions of its habitat - low temperatures do not favor sharks for maneuverability and agility.
With such slowness one could die of hunger, but the polar beauty looks for victims on its own. All that remains for her is to attack the seals sleeping in the water.
2. Giant (or gigantic) shark
In second place is giant shark is the biggest from relatively dangerous sharks. Photo not the most pleasant - the gaping mouth is both scary and disgusting. The size of females is about 10 m. Males are slightly smaller. A couple of centuries ago, fishermen caught 12-meter specimens. There is an opinion that even today it is quite possible to come across a truly giant shark– up to 15 m long.
However, the likelihood of meeting even an ordinary representative of the species is very low - due to the mass extermination of these sharks, there are only a few of these sharks left. The horror story feeds on plankton and small fish, but it is better for humans not to swim near it. The shark has sharp scales that can easily hurt.
You are already one step away from finding out how much does the biggest shark weigh?, about the size of the latter and about its diet.
The largest shark on the planet - whale shark . The average length is 12-15 m, but more impressive dimensions are not uncommon - 18-20 m. Weight himself dimensional specimen – 36 tons.
To satisfy their hunger, a “mid-size” whale needs at least 200 kg of plankton. That the most shark in the world eats small things, as almost any schoolchild probably knows.
Megalodon
Which a hit selection with no surprises? U many, perhaps the question has arisen - what does another species have to do with it, if we have already decided on the first position? In fact, the whale fish is indeed the largest in size. But - in modern realities. Among the extinct species, another fish is in the lead.
Megalodon shark– the undisputed record holder of those distant times and species. Unfortunately, on video of the biggest shark didn’t get it - the fossil fish disappeared long before the development of our technologies. According to scientists, the size of the mega-fish was in the range of 12-18 m. At the same time largest shark in the world megalodon was heavier than a modern whale - about 50 tons. Due to its size, the shark even fed on similar, but smaller, species.
Instructions
Most sharks have an elongated and spindle-shaped body. The color of their skin depends on the type of fish itself and can be blue or gray, even white (white shark). Some sharks are generally colored with spots or stripes (for example, the tiger shark). Their head has a peculiar extension in the form of a nasal outgrowth, which is called a rostrum. On the sides of the shark's head there are gills - several slits through which oxygen-enriched water passes. In ancient species of sharks there are usually 5 of these slits on each side, and in modern ones - up to 7 pieces. Sharks' eyes are black and large. They are located on the sides of the head. Behind the eyes you can see two holes leading into the pharynx. Ichthyologists call them squirters, which are rudiments of gill slits.
It is curious that there is not a single real bone in the body of sharks. Their skeleton consists entirely of cartilage, and the skin of most representatives of these formidable predators is covered with rather sharp spines. It is worth noting that residents of some islands and peninsulas use such shark skin as an abrasive material for polishing wood. The paired limbs of sharks are pectoral and pelvic fins located horizontally. The caudal fin is multi-layered, and its shape differs in different species of sharks. This is due to certain living conditions of a particular species of these fish. It is worth noting that sharks are fish that do not have a swim bladder. Other organs compensate for the negative buoyancy: an enlarged liver, fins and a cartilaginous skeleton.
Sharks' mouths are located at the bottom of their heads. This is not entirely convenient for the fish itself: in order to grab its prey, it has to turn on its side or even on its back. The teeth of most of these creatures are very large, sharp and jagged at the edges. They have a cone shape. A distinctive feature of the jaws of all sharks is the non-standard arrangement of teeth: they are arranged in five (or even seven) rows. In addition, the teeth of these fish easily regenerate if broken six times in their lifetime.
Sharks are found in almost all oceans and seas of the planet. These fish are the most ancient on Earth. Currently, there are more than 450 species of them - and this is not all the species known to science. Sharks are very voracious fish; there is even a saying: what a wolf is on land, a shark is in water. Many of these fish swim in whole schools behind ships and boats in anticipation of water will fall something edible and not very good. The fact is that they can swallow everything: and cans, And empty bottles, and other rubbish. If we talk about record-breaking sharks, the smallest shark in the world is recognized as a deep-sea shark, its body length is only 17 cm, and the largest is a harmless whale shark with a body length of 20 m.
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