Sharks are one of the oldest inhabitants of our planet. Scientists consider them to be the same age as dinosaurs. But sharks turned out to be much smarter than these ancient lizards and were able to survive to this day.
Now in nature there are several hundred species of these predatory fish. They may differ in body size, color, and feeding method.
After watching another horror movie starring sharks, many people are interested in the question: how many teeth does a shark have? It is very difficult to answer such a question. To do this, you would have to catch a shark and try to count its teeth. However, such a meeting would end tragically for most people. Therefore, we suggest that you seek help from specialists.
Shark: description and photo. What does a shark look like?
There are over 500 different species of sharks. The superorder is characterized by a variety of sizes, shapes and other features. For example, the smallest deep-sea shark with a length of 17 cm is considered the smallest. One of the largest is the whale shark (up to 20 m in length). The same applies to weight - from 200 grams to several tens of tons.
Unlike bony fish, sharks have a skeleton made of cartilage tissue. At the same time, it is endowed with a sufficient level of rigidity. The skeleton includes 4 sections:
- spinal column (axial skeleton);
- unpaired fins;
- paired limbs (pelvic and pectoral fins);
- scull.
Anatomy of a shark
The maneuverability and speed of movement of a fish is ensured by several factors. The fish performs wave-like movements using its body, tail and fins. The tail fin, which includes two blades, serves as the main “engine” for the shark and also helps set the direction of movement. The fins located on the sides allow you to increase the speed of movement and perform maneuvers.
Shark tail fin
Each species of shark has certain anatomical features of its tail.
For example, a white shark moves very quickly, so its tail fin blades are almost identical. In other species, the upper lobe is larger than the lower one. Interesting fact : when a shark slows down, dives down or rises up, the paired fins along with the dorsal fins help it maintain balance. In this case, the fish is not able to swim in the opposite direction.
Dorsal fin of a shark
The body of sharks is covered with very strong placoid scales. Each scale is a diamond-shaped plate with a spike at the protruding end. Shark scales are called dermal denticles because they are similar to teeth in terms of strength and structure. The scales fit tightly to each other. Because of this, at first glance it seems that the skin is perfectly smooth and even. But if you run your hand over it in the opposite direction, from the tail to the head, a rough effect immediately becomes noticeable - the skin feels like sandpaper to the touch.
Shark skin under a microscope
The musculature of a shark is represented by several muscle groups:
- cardiac;
- somatic (red and white, responsible for body movement);
- visceral (muscles in blood vessels and internal organs).
The body of sharks is quite simple, and the metabolism is slow. Because of this, they cannot undergo prolonged physical activity. As a result of intense activity, excessive amounts of lactic acid accumulate in the body, which can negatively affect internal processes.
Sharks breathe oxygen from the water through their gills. The role of their respiratory organs is performed by the gill slits. They are located in front of the pectoral fins. The number of slits depends on the type of shark - from 5 to 7 pairs.
Shark gill slits
Due to the work of the heart, blood in sharks is transported through the gill artery into the vessels that are located in the gills. There the blood is saturated with oxygen and sent to the organs. However, blood pressure is not enough to supply the entire body with enough oxygen. Therefore, the shark is in constant motion - muscle contraction increases blood flow.
Bony fish have a swim bladder filled with gas. Sharks do not have it, so buoyancy is provided by the huge liver, as well as the skeleton and fins. And sand sharks imitate a swim bladder, filling the stomach with air.
Most sharks are cold-blooded with the exception of about 8 species. In white, blue and other sharks, certain parts of the body have a higher temperature than the environment. This allows them to move faster in cold water. Active muscle work contributes to an increase in temperature.
The stomach of sharks is U-shaped and can easily stretch. The liver occupies about 30% of the volume of the entire body. In addition to participating in buoyancy processes, it serves as a kind of storage facility, which contains useful substances and energy reserves.
The shark spends its accumulated resources for a very long time and gradually after eating, so it is capable of starving for a long time. For example, a shark weighing 150 kg requires about 80-90 kg of fish per year. From time to time, fish have to empty their stomachs of food debris. To do this, they turn it out through the mouth without causing absolutely any damage to the teeth.
For sharks, the main sensory system is a well-developed sense of smell. They are excellent at distinguishing odors by passing water through their nostrils to the receptors.
Interesting fact : some sharks have such sensitive receptors that they recognize the smell of blood in a ratio of 1 to 1 million. That is, they are able to sense it at a great distance, dissolved in a large mass of water.
The vision of some fish species is characterized by increased acuity. In addition, they are able to distinguish small details and some colors. Perception frequency – 45 frames per second. Some species have blinking eyelids, others do not. To protect their eyes from damage, the second type of shark rolls them up during an attack.
Shark eyes and nostrils
The organ of hearing is the inner ear, located inside the cartilaginous capsule. Predatory fish are able to detect low-frequency sounds and infrasound. The ear also helps maintain balance.
Interesting fact : the white shark has the best hearing among sharks.
Sharks have a sensitive organ - the lateral line, which runs inside the skin along the side of the body. It reacts to water fluctuations and allows fish to navigate in space, hunt and perform other vital functions.
Shark lateral line
How does a shark's jaw work - the structure of a shark's jaw
All sharks existing on earth today have the same jaw structure. Therefore, if you know how the jaw of one species of shark works, you can confidently say that the jaw of another species of shark works as well.
Diagram of the structure of a shark's jaw
Main parts of a shark's jaw:
- Pay attention to the facial, anterior part of the skull (scientifically “visceral”). The jaw arch is attached to it (another name is the “visceral arch”). It consists of two main parts: the palatoquadrate cartilage and the Meckel's cartilage. Ligaments hold, fasten together these two components of the ligament.
- The first cartilage is called palatoquadrate due to its shape and location. It replaces the upper jaw, and the lower cartilage, called Meckel's cartilage, does what the lower jaw does.
- Behind the first arch you will find the hyoid. Its components are three cartilages: one of them is in single quantity, and the other two duplicate each other.
- The first cartilage, the one that does not have a double, is called by scientists the hyomandibular, or pendulosa for short. It moves easily from side to side and is directly attached to the skull in the area of the auditory region using ligaments. At the other, opposite end of the suspension there is a maxillary arch and a hyoid, a paired section of the hyoid arch. How are the hyodes attached to each other? Correct answer: they are attached to each other using cartilage. Also, this same cartilage is attached to the tongue of the shark itself.
An interesting fact about the shark’s tongue: unlike the human tongue, it consists not of muscles, but of two types of tissue: consisting of mucus and what is commonly called connective tissue.
The jaw of sharks is attached to the skull by the upper element of the hyoid arch. This type of attachment of the arch to the brain is called hyostyly.
How many teeth does a shark have?
The shape, size and number of teeth depend on what kind of life the shark leads and what it eats. Teeth are the main weapon of these predators and their growth continues throughout the entire life cycle of the fish. This is nothing more than modified placoid scales covering the skin.
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Most sharks have teeth growing in several rows - from 3 to 20 on both jaws. Each row contains about 30 teeth. Thus, an adult can have 200-15,000 teeth. However, they do not have roots, so teeth change quite often and unnoticed by the predator itself.
White shark teeth
Diet primarily affects the size and shape of teeth. Most predator sharks have sharp, cone-shaped teeth (about 5 cm long). If fish feed on hard-shelled food, they need flat, crushing teeth. Sharks that hunt large prey have wide and serrated teeth. Fish that feed on plankton have small teeth - only 3-5 mm.
Number of teeth in different types of sharks:
- white and brindle - 5-6 rows, up to 300;
- mustachioed - 5-7 rows, up to 500;
- hammerhead shark – 15-17 rows, up to 700;
- sand tiger - 42-28 rows, up to 1300;
- giant – 6-10 rows, up to 2000;
- whale - 18-20 rows, up to 15,000.
Whale shark mouth
Human use of tools[edit]
Hilbertian weapon with shark teeth.
In Oceania and the Americas, shark teeth were commonly used to make tools, especially weapons such as clubs and daggers, but also as wood carving blades and cooking tools. For example, various shark-tooth weapons were used by the native Hawaiians (see example here [21]), who called them leiomano. [22] Some types were reserved for the royal family. [23] Guaitaca (Weittaka) offshore Brazil arrowhead with shark teeth. [24] Remains of weapons with sharp shark teeth, as well as flint replicas of shark teeth, were found in the Cahokia Mounds in the upper Mississippi River Valley, more than 1,000 km (620 mi) from the ocean. [25] Rongorongo tablets from Easter Island are reported to have been shaped first and then inscribed using chopped shark tooth. [26]
Fish or mammal?
The term "mammal" refers to feeding its young with milk. Sharks do not do this, so they are clearly classified as fish. In addition, they breathe using gills.
Many sharks are comparable in size to large marine mammals, such as some species of whales. However, this does not give reason to classify them in this category.
Comparison of the sizes of whales and white sharks
The appearance of some shark species can also be misleading. For example, the frilled shark looks like an eel, the carpet shark lives on the bottom, and the hammerhead shark is easily recognizable by its characteristic head shape.
Interesting fact : an unusual representative of sharks, the carpet shark, has an extraordinary appearance, swims poorly and most of the time lies on the bottom waiting for fish to swim by.
Behavior and lifestyle
It is believed that sharks prefer to lead a solitary lifestyle and not form schools. However, from time to time they can be seen in groups, and quite large ones at that. Most often these are places with abundant food. Sharks also live in groups during reproduction.
Certain species of sharks prefer not to change their usual habitat. Others migrate, covering distances of thousands of kilometers. The migration system of fish is much more complex than that of birds. There is also a hierarchical system among sharks, according to which some species are subordinate to others. For example, despite the same size, the silky shark is subordinate to the white shark.
Sharks do not always attack immediately as soon as they see an enemy. They communicate through movements. If an unwanted object approaches, the predator can give a threatening signal by moving its fins more intensely.
School of hammerhead sharks
The average speed of sharks is about 8 km/h. If necessary, this figure can increase to 19 km/h. Some species (white shark, etc.) make high-speed bursts of about 50 km/h. This ability is inherent in them due to the previously mentioned temperature difference.
According to new research, sharks are capable of displaying playfulness, curiosity, intelligence and other signs of intelligence. They often overcome difficulties as part of a group.
How do sharks sleep?
For a long time it was believed that sharks cannot sleep because they need to constantly move to obtain oxygen. However, experts say that at least some species of sharks (demersal) can remain dormant for some time.
Interesting fact : only some sharks can remain stationary for a long time (during sleep), for example, the whiskered nurse shark. At the same time, they pump water through their gills and receive oxygen.
Whiskered nurse shark resting on the bottom
When sleeping on the bottom, sharks do not close their eyes or use their nostrils. However, they may involve squirters. Some species can sleep while moving because their spinal cord is responsible for movement. Another theory is the ability to turn off the hemispheres of the brain in turn.
Sharks can also “take a break” in underwater caves, where there is a fairly strong current. Interestingly, in one of these caves, scuba divers discovered Caribbean reef sharks. They appeared to be sleeping, despite the fact that this species is an active swimmer.
How and what do sharks drink?
Strictly speaking, sharks do not need to regularly drink water in the strictest sense of the word. Being in salt water, they absorb it constantly, and through the walls of the stomach the fresh component is absorbed into the blood and spread throughout the body.
At the same time, the fluid in the shark's body contains less salts than the water in the environment. A physical process called osmotic pressure occurs - a liquid with a lower concentration of salts rushes towards a liquid with a higher concentration. They contact through the skin of the fish. Thus, the sharks’ body gets rid of excess salt.
Interesting fact : sharks, which are able to live in both salt and fresh water (or only fresh), have the unique ability to adapt their body to life in a certain environment. For example, a blunt-nosed shark.
Gill arches in a shark's jaw
Without gills, a shark cannot breathe. They are the main reason why oxygen gets inside the shark's lungs. The shark periodically draws water into its slightly open jaws. From here it goes to the gills, and oxygen begins to enter the shark’s lungs. That is why the shark’s jaw is always slightly open, so that if necessary, it can quickly enrich its body with oxygen. And the arrangement of the teeth in the jaw helps it do this as efficiently as possible.
The gills are connected to each other by the attachment of cartilaginous copulas. They are partially fused with each other. Why are gills arranged this way? There is a reason for this.
Before we find out, let’s add one more important fact. The gills of a shark have small processes that are thin and resemble stamens. They are placed so as to be at the same level with each other. For what?
Due to their location, the stamens in the shark's gills, which are attached through cartilage to the jaw, prevent large volumes of food from falling out through the gills. Because of this, the shark can hunt less and immediately digest more food than if some of it fell back into the water through the gills. Thus, we can conclude that gills not only help the shark breathe, but also help save the shark’s energy and time.
Shark gills in shark jaw
How long do sharks live?
The average lifespan of most sharks is about 30 years. However, there are also long-lived species. These include whale sharks, spotted spiny sharks, and Greenland polar sharks, which can live up to 100 years. It is the Greenland polar shark that is considered the record holder in terms of longevity. For example, the age of one of them would be estimated by scientists at 392 years with an error of 100 years. On average, the species lives up to 272 years.
Interesting fact : in 2022, scientists discovered the oldest and at the same time the largest shark, a representative of the Greenland polar species. Estimated age is about 500 years. The fact is that over the course of a year, sharks of this species grow 1 cm in length. And the length of this individual was 5.4 m.
Greenland shark
Longevity is directly related to a shark's teeth, because if a predator loses its main weapon, it will not be able to feed.
Shark jaw, teeth, dentition: how many, how are they arranged and why?
The most important part of a shark's jaw is, of course, the teeth. The shark's teeth are arranged in two rows. Why? The reason is that sharks constantly use their teeth to hunt and crush food. Shark teeth are weapons of attack and defense. Therefore, over the course of its entire life, a shark can lose all its teeth. This is due to the fact that they are weakly attached to the jaw.
Unlike humans, they do not have roots to support them in their depression. Because of this, when a shark bites into meat, the tooth may remain inside the prey due to the stiffness of the fibers. Therefore, the second row of teeth plays the role of spare teeth. If the shark runs out of teeth on the first row, it will be able to use the second and third.
Important fact: a shark's ability to lose its teeth is also a means of self-defense. When a shark hunts, it opens its mouth wide and bites its prey. During this process, a piece of prey may occupy the entire mouth, and the shark will not be able to breathe. And she breathes by swallowing water and extracting oxygen from it. In this case, it is easier for the shark to separate several teeth from the front jaw, release the prey and then attack again. Otherwise, she may lose access to oxygen.
Don't forget about shark diseases, which also damage teeth and lead to their loss. Sharks also have plaque on their teeth that causes caries or tartar. This problem that sharks face is very similar to what happens to human teeth.
Also, the way a shark's teeth are positioned has a direct connection with how oxygen gets inside the shark's lungs. The breathing process of a shark occurs as follows: the shark opens its mouth, water enters it. After this, oxygen is supplied to the shark's lungs through the gills. For this reason, the shark’s mouth should not be completely closed the entire time it is in the water. And the teeth grow so that it is more convenient for the shark to swallow water and extract oxygen from it.
Where do sharks live?
Sharks are common in the waters of the world's oceans. Thus, they live in all oceans and seas. Cartilaginous fish prefer coastal waters, reef zones, equatorial and near-equatorial waters.
Some species of sharks feel equally comfortable in both salt and fresh water. Therefore, they can swim into rivers. These species include the blunt-nosed shark, the common gray shark and others. On average, predators prefer a depth of about 2000 m, sometimes swimming 3000 m deep.
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Habitat of the white shark
Sharks of the Black Sea
Due to the high content of hydrogen sulfide in the waters of the Black Sea, the diversity of sharks that cannot tolerate it is small here. There are 2 species - the katran and the cat shark. These are small-sized individuals that do not pose a danger to humans. The only thing is that the body of the katran is strewn with thorns, contact with which is fraught with negative consequences.
There are also rare cases when predatory species of sharks swam into the waters of the Black Sea. For example, a great white shark can temporarily swim to the southern part of the Crimean coast and the western territories of the Krasnodar Territory.
Ninja Lantern Shark
Ninja Lantern Shark. (Image credit: Vásquez VE et al. Journal of the Ocean Science Foundation, 2015.)
The credit for the common name for these secretive sharks goes to a pair of eight-year-old children, cousins of the scientist who discovered the creature. According to Hakai Magazine, researcher Vicki Vasquez chose the name "ninja lantern shark" after her young cousins suggested that the sharks' smooth black skin and delicate bioluminescence, which is used to blend in with sunlight filtering from the ocean's surface, reminded them of "super ninja" ()
These attractive-looking sharks also have a funny scientific name: Etmopterus benchleyi, after Peter Benchley, author of Jaws (Doubleday: 1974).
Ninja lantern sharks are small in size, growing to only 0.5 meters in length. They live off the coast of Central America.
What does a shark eat?
The diet of sharks depends on the specific species, as well as its habitat. In general, it can be called diverse. Most representatives are carnivores. Some species are unpretentious, so they feed on everything that comes their way (for example, a tiger shark). The main part of the diet is fish, plankton, small mammals, and crustaceans.
Shark jumps out of the water
Thus, sharks that live on the bottom feed on crabs and other crustaceans. To do this, they have teeth that can bite through shells. Blue shark, mako, lamna hunt sea fish while on the move. The white shark prefers large fish and mammals. Whale and basking sharks, despite their impressive size, feed on plankton.
Interesting fact : a whale shark can open its mouth up to 4.6 meters.
carpet shark
The carpet shark is hiding on the ocean floor. (Image credit: Sim Haichuin/Getty Images)
What do you get when you cross a fish with a 1970s rug? Probably a carpet shark. These bottom dwellers of the family Orectolobidae are camouflaged with mottled orange patterns. Sharks even have a frill of sensory lobes that lines their jaws.
There are a dozen species of carpet sharks found in the eastern Indian Ocean and western Pacific Ocean. The largest grow to more than 3 meters in length. The carpet shark is also called "Wobbegong", which means "shaggy beard" in the indigenous Australian language.
Natural enemies of sharks
It is noteworthy that sharks exhibit predatory qualities from birth. For them, natural selection begins from the moment they are born. Cubs born earlier than others get rid of their brothers and sisters. Also, newly hatched sharks are preyed upon by larger species.
Natural enemies of sharks:
- marlin;
- swordfish;
- dolphins, killer whales;
- saltwater crocodile (freshwater).
Natural enemies of sharks
Representatives of the billfish family can attack sharks using their long and powerful “spear”. The same applies to swordfish, which, when attacked by a shark, pierces its gills with its long nose.
Dolphins and killer whales are the main rivals of sharks in terms of food production, since the former feed on fish, the latter on large mammals. And this is the basis of the diet for predator sharks. In addition, sharks suffer from bacteria and various parasites.
Shark breeding
Sharks are characterized by internal fertilization. Moreover, depending on the type, they can be:
- viviparous;
- ovoviviparous;
- oviparous.
Sharks have a long period of puberty - on average about 10 years. A whale shark is capable of procreation only at 30-40 years of age. The incubation period also varies significantly - from a couple of months to 2 years.
Fish that reproduce oviparously lay 2-12 eggs. In this case, the eggs are covered with several shells. Including the external horn-like one. It protects the offspring from predators. Cubs become independent immediately after birth.
Shark egg capsules
In ovoviviparous fish, the young remain in the oviduct for some time. It is at this stage that natural selection operates and out of all the offspring, a maximum of 2 strongest individuals remain. The size of the cubs varies depending on the species. The offspring of the tiger shark are about 50-76 cm in length, and the white one is one and a half meters long.
baby shark
Today's day
By the end of the Pliocene, the climate again entered a period of change. The era of ice ages begins, sea levels fall, and the map of currents changes, which leads to the disappearance of a number of shelf ecosystems. Plankton fields and migration routes of small fish are shifting to cold waters. Following them, whales leave and new predators come. Orcas. Their warm blood allows them to hunt in both the tropics and polar waters. Fast and incredibly intelligent, pack hunters are capable of taking down any prey. They drive schools of fish into traps along rocky shores. They snatch seals right from the shore. Huge whales are gutted alive. And they look at shark liver, rich in fat, as a delicacy.
About 2.6 million years ago, megalodon became extinct, leaving no successors. But with its extinction, the story of sharks is not over at all. Today, as millions of years ago, they remain a successful class of fish, occupying a variety of ecological niches. Benthic species, with camouflage coloring and a flattened body, are common in the tropics. Pelagic hunters, such as lamniformes, roam the seas of the entire planet. The whale shark, although it feeds on plankton and not whales, is the largest modern fish and reaches 12–18 meters in length. And large sharks, such as white and tiger sharks, maintain their status as apex predators, being at the top of the food pyramid.
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Population and species status
According to recent data, about 25% of all shark species are on the verge of extinction. The total number of fish is declining at a fairly high rate. There are several reasons for this:
- Low reproductive capacity - sharks focus on the quality of the offspring produced, not the quantity. That is why, of all the cubs, only a few of the strongest remain.
- Shark fishing, in particular, is illegal.
- Reducing the amount of food that predators eat. This includes a decline in the number of mammals.
- Pollution of the World Ocean waters with waste. This is especially true for plastic.
Garbage continents (the Great Pacific Garbage Patch is highlighted in red)
It is worth noting that sharks, especially hungry ones, tend to consume everything in their path. That's why they are attracted to large piles of garbage floating in the ocean - they create vibrations. Sharks are also quite curious.
The concept of supernumerary teeth. Shark teeth as one of the types of pathology
Shark teeth (polyodontia, hyperdontia) is a type of dental pathology in which the total number of permanent or temporary teeth is greater than normal. In other words, there are additional or supernumerary teeth in the mouth.
Hyperdontia in humans is a fairly common disorder in the dental system. Out of 20 people examined, one has shark teeth. Moreover, the majority grow 1 supernumerary tooth, but there are cases when the patient has 3 shark teeth or more.
Science does not provide the exact cause of shark teeth, but the number of patients with an increased number of teeth is not decreasing.
At what age can shark teeth erupt?
Shark teeth in humans usually erupt along with the rest of the teeth. Polyodontia is detected in the following periods:
- During the period of formation and development of temporary occlusion. The first teeth appear at the 6th month of a child’s life.
- The period of mixed dentition is from approximately 6 to 12–13 years. At this time, both baby and permanent teeth are present in the mouth.
- During the period of formation and development of permanent occlusion, the first permanent tooth appears at 6 years of age, then milk teeth are systematically replaced by permanent ones. Complete replacement occurs on average by 17–25 years.
The main reasons that lead to the appearance of shark teeth are late replacement of baby teeth, underdevelopment of the jaws and an excessive number of teeth.
Considering the periods described above, it is necessary to visit the dentist at least once every 6 months in order to detect hyperdontia, as well as to prevent diseases of the masticatory apparatus.
Shark fishing
More than 100 species of sharks are fished, as are many other fish. The fishing industry is interested in shark meat, fins, cartilage, liver and skin. Fishing is most active in the Atlantic Ocean, followed by the Indian and Pacific Oceans.
Up to 100 million individuals are caught every year. Bans and restrictions on fishing are gradually being introduced, but its intensity is only increasing. Sharks are caught not only as a target fishery, but also accidentally - during the catch of other fish.
Shark and diver
There is a separate type of fishing - shark fin fishing. It is banned in some countries. Other reasons for catching sharks include increased danger on beaches and the threat of a decline in the population of other fish species.
frilled shark
Frilled sharks have remained virtually unchanged for 80 million years. (Image credit: Awashima Marine Park/Getty Images)
These sharks can kill. Frilled sharks (Chlamydoselachus anguineus) have 300 three-pointed teeth arranged in rows. Growing up to 1.5 meters in length, frilled sharks punch above their weight when targeting prey, using their sharp, backward-facing teeth to catch fish, squid and other sharks twice their size.
Surprisingly, these sharks have remained basically the same for 80 million years, since the dinosaurs went extinct. According to the International Union for Conservation of Nature (IUCN), they live between 20 and 1,500 meters underwater in the Atlantic and Pacific oceans.
Shark attack on a person
According to international statistics, the largest number of shark attacks on people are recorded in countries such as the USA, Brazil, Australia, New Zealand and South Africa.
However, there is also unofficial data according to which African countries top the ranking of the most dangerous countries. Populations of dangerous and fairly large sharks live near Ghana, Tanzania, and Mozambique. Most attacks occur in ocean waters rather than in the seas.
White shark attacks (2015)
There are many myths surrounding sharks. They are considered the most dangerous predators, whose main goal is to attack people. This is only partially true. Sharks are indeed true predators and all safety tips must be followed.
However, most sharks attack people by mistake, confusing them with their real prey. Only some species, such as white, tiger and other sharks, can attack without any reason. In general, concerns about these fish are greatly exaggerated.
Interesting fact : in the list of threats that await a person in the water, the shark ranks last.
The structure of a shark's jaw - why is it unique?
A shark's main weapon is its teeth. Even a person who has never read about the structure of a shark’s jaw knows how sharp and dangerous they are. They are located in two rows. The number of teeth reaches ten thousand. And the record holder for the number of teeth is the whale shark. The total number of teeth is fifteen thousand.
Another amazing fact about shark teeth. Scientists have determined that they are scales of their own kind. But sharper and tougher. They include dentitis. However, the roots of shark teeth are very small. The second row of teeth plays the role of spare teeth. If the shark runs out of teeth on its first jaw, it will be able to use others from its second or third jaw.
How will a shark replace a lost tooth if the teeth are nearby and the rest of the teeth on the shark's jaw are still intact? This happens very quickly; the tooth located on the back jaw is automatically forced forward. Because of this, it does not have the same root as a human tooth. Thanks to this, the tooth can easily move and replace the lost one.
Sharks often replace their teeth, either as a preventative measure or due to diseases such as tooth decay. Predators such as tiger sharks replace teeth with entire jaws, and over the entire period of their existence replace tens of thousands of teeth with each other.
The jaw structure of sharks is identical. However, the shape of one shark's teeth is different from the shape of another shark's teeth. For example, a white shark's teeth are rectangular in shape, with smooth edges. To tear apart prey, a white shark only needs one row of sharp, jagged spaces on each tooth. But a more dangerous predator, the tiger shark, has two rows of notches on each tooth.
The record holder for length is the teeth found during excavations and reaching a length of 15 centimeters. They were found to be part of an extinct species of shark called megalodon.
The rate at which some shark teeth replace others depends not only on the circumstances, but also on the species of shark. For example, in representatives of the lemon shark species they change every seven days. And for a great white shark, it takes about 240 days for the teeth to naturally replace each other in the front jaw.
The shape of the teeth always has very sharp edges, with the help of which the shark easily tears apart what gets into its mouth. Due to the structure of its jaw, a shark can bite off and swallow large pieces of meat in a very short time. Although the speed of eating prey in horror films is indeed exaggerated, in nature the shark can also finish off its prey in a very short time.
The number of teeth may vary among sharks of the same species, but of different ages. As the number of years lived increases, the number of teeth also increases. Also, shark teeth often suffer from collisions with boards, paddles, surfboards and boats.
The shark's diet consists of large marine animals such as seals and fur seals. Their skin is very tough and sometimes you need to give up several of your teeth to bite through it. Sharks chose these animals as their prey precisely because their bodies contain large amounts of fat. And sharks need fat for large reserves of energy, which will give them the ability to move quickly, maintain the body temperature necessary for life and get their own food.
The shark's jaw is designed so that the shark can survive and feed itself
Thus, we can conclude that the structure of a shark’s jaw and the location of its teeth is formed due to many factors such as: prey, the need for fast movement, the need to obtain oxygen from the water and swim with its mouth slightly open, the presence of dental diseases and, most importantly, constant use teeth and the need to replace lost ones.
Read about cases of shark attacks on humans in the article:
- The most dangerous killer sharks for humans: top 10 list, description, photo
- Are there sharks in the Black Sea?
Keeping sharks in captivity
Only a few species of sharks can be found in captivity. Known or, conversely, rare species are of greatest interest. As a rule, they are distinguished by their large size and aggressive behavior. It is quite difficult to catch such sharks, as well as transport them. It is important not to damage them.
Whale shark in the aquarium
Specialists will also face difficulties when relocating an individual to an artificial tank. It must be spacious and durable enough, contain all the necessary equipment so that the shark feels safe. Support for normal functioning is required.
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Sharks in culture
Sharks, as unique and interesting creatures, could not help but become part of the culture for many peoples of the world. At a minimum, everyone has probably seen Western films in which sharks act as real monsters.
But this is not the entire role of fish in cultural heritage. They are mentioned in Greek mythology, Japanese, Polynesian culture. In particular, for the inhabitants of the Hawaiian Islands, sharks are not dangerous predators, but sea guardians who protect the local people.
Australian aborigines regard them as gifts of nature intended for humans. The Chinese consider sharks as a fishery, namely, they are considered valuable in the field of food industry and traditional medicine.
In popular culture, a shark is an essential element of a horror film or thriller about sea monsters. Examples of films featuring predator sharks:
- "Jaws" (1975);
- "The Abyss" (1977);
- "Deep Blue Sea" (1999);
- “The Shallows” (2016), etc.
Introduction
Sharks. These ancient creatures arouse interest among people, mixed with a feeling of unconscious fear. There are more myths and legends about sharks than about any other sea creatures. It is believed that they are the most advanced predators on our planet. Having reached the limit in the development of predatory fish, they have remained unchanged for hundreds of millions of years. The imagination of writers and screenwriters is fueled by stories about their attacks on people. And enthusiasts dream of finding the most dangerous predator, megalodon, in the depths of the sea. Today we will go back to the distant past and, together with sharks, will go through the thorny path of their evolution.
Types of sharks, names and photographs
In total, there are about 500 species of sharks. They have a rather complex classification, but experts identify 8 main orders (in brackets are typical representatives of the order):
- Carchariformes (basking hammerhead, silky, tiger, bull shark, blue);
- Lumniformes (giant, white, fox, herring, false sand, sand, largemouth);
- Heterodontoids (zebra bull, helmeted, African horned);
- Polygillidae (fried, sevengill);
- Sawtooth (pilonose);
- Wobbegongs (whale);
- Katraniformes (southern Katran);
- Flat-bodied (California squatina).
The most famous species
The white shark is characterized by aggressive behavior. Average age is about 70 years. It reaches 6 m in length or more, and such individuals weigh up to 2 tons. It is distinguished by good camouflage in the form of skin on the upper part of the body in shades of gray, brown, and green. The lower part of the body is much lighter. Has a highly sensitive sense of smell. Distributed in all oceanic waters.
White shark
The whale shark reaches an average length of 6-8 m. But this species is characterized by external diversity, so there are both small individuals and giants up to 20 m long. Considered the largest shark. Despite its possible dimensions, it is not dangerous for people. The structure of the jaws and teeth is designed to capture small sea food along with water. The characteristic color is dark skin with large white spots on the back and sides.
Whale shark
The height of a giant shark is up to 15 m, weight – up to 4 tons. It ranks second in size. It also feeds on plankton. It can lead a solitary lifestyle or form flocks. It has an unremarkable brown-gray color.
Giant shark
The largemouth shark grows up to 5 m in length. It is dark brown in the upper part and light brown in the lower part. A characteristic feature is a large mouth, up to 1.5 m long, with small teeth. It feeds on small sea creatures, attracting them with luminous phosphorites.
Largemouth shark
The tiger shark is a 4-meter specimen with bright striped colors. But this color is characteristic only of young fish, while in mature ones the skin becomes gray. It is dangerous for people because it moves quickly and has sharp teeth.
Tiger shark
The bull shark is common in all waters, including the ability to swim into fresh water bodies. It also poses a danger to people. The average length is 3 m. It is distinguished by a specially shaped muzzle with which it attacks enemies. Therefore, it has a second name - blunt-nosed.
Bull shark
The frilled shark looks more like a snake and is considered one of the ancient representatives that has retained its original appearance. It reaches a maximum length of 2 m. Due to the structure of the jaw, fairly large fish are swallowed whole.
frilled shark
The mako shark grows up to 3 meters and weighs about 100 kg. It is distinguished by its aggressiveness, developed sense of smell, and high speed. Dangerous for people. It has a gray-blue color with light skin in the abdominal area.
Mako shark
Interesting fact : when hunting, a mako shark can jump 6 m out of the water.
The hammerhead shark has a characteristic feature - a flattened hammer-shaped head. Poses a danger to people. Some individuals reach 8 m in length.
Hammerhead shark
Interesting fact : The location of the hammerhead shark's eyes allows it to have a 360° vision.
The fox shark reaches 5 m. It has a unique tail with a long upper blade and a short lower one. Using its tail it stuns fish and thus feeds.
fox shark
Whiskered shark , also called a dog shark because of its specific appearance - whiskers and folds at the corners of its mouth. The length is up to a meter, with the tail taking up most of it. Swims quickly and successfully hunts small fish.
Whiskered nurse shark
Reef shark with a thin body and a wide head. It grows up to 1.5 m and weighs only 20 kg. Usually has a dark gray color with sparse spots. Distributed among coral reefs, lagoons, and sandy shallows.
Reef shark
The lemon shark has a yellow skin tone mixed with pink and gray. Grows up to 3 m in length. Often forms groups, especially young individuals. Shows aggression towards people.
lemon shark
The freshwater shark is a rare representative of fish that lives in fresh water all its life. Length – up to 3 m. Dangerous for both people and other animals approaching the water. It has a gray-blue color with a light belly.
Freshwater shark
The dwarf shark is the smallest representative, about 17 cm long. It is considered little studied, since it belongs to deep-sea fish. Capable of emitting green light from her eyes.
Dwarf shark
The cat shark is a small specimen up to 1 m long with a bright coloration in the form of a dark shade with numerous spots. It is distinguished by its flexible body and elegance. Does not pose a danger to people.
cat shark
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 large representatives of 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.
The largest sharks in the world
Species of sharks that are particularly large in size:
- Megalodon is a long-extinct species, but according to the teeth found, the length was about 15 m, weight up to 40,000 kg.
- Large whale shark - length 12 m or more, weight 21,000 kg.
- Giant shark - length 9-10 m, weight 4000 kg.
- Tiger shark - length 7.5 m, weight 939 kg.
- Great white shark - length 6 m, weight 1500 kg.
- Greenland shark – length 4-6, weight 1020 kg.
- Hammerhead shark - length 5-6 meters, weight 844 kg.
Megalodon and white shark teeth
