What kind of fish is a shark? Mammal or fish - shark is an interesting question for many. Great white shark

First of all, sharks are forced to move more than any bony fish - because their buoyancy is not provided by a swim bladder. What does this mean, other than that a dead shark sinks to the bottom like a stone?

The fact that sharks do not have the opportunity to wait for food, relying on the constant presence of wounded, sick or dead prey - they need to move in order to live.

These fish have perfected their hunting techniques, studied the habits of their favorite prey, and are determined not to be left without food.

Predatory bony fishes hunt alone - from ambush or while chasing prey. Sharks hunt in a similar way, but they also use another technique, characteristic not of fish, but of mammals - these predators can, and each member of the hunting team knows his task!

Group shark hunt

The first information about group hunting of sharks was obtained more than 100 years ago - in 1915, Russell Coles, one of the first researchers of predators, informed ichthyologists about an extremely amazing hunt that he was able to observe.

At Cape Lookout, off the coast of North Carolina (USA), Coles noticed how about a hundred big-eyed sand sharks (Odontaspis noronhai) in a wide front surrounded and drove a school of large bluefish into the shallows, after which they simultaneously attacked them.

Watch video - Shark hunting together:

Never before have predatory fish hunted so coordinatedly; this method is more common among bottlenose dolphins, driving schools of mullet into the shallows. The fact is that a frightened fish in a school obeys the herd instinct and is ready to break out of the line of predators at the first opportunity.

It is difficult to hold a mass of fish and force them to retreat to the shallows. Any mistake - and they will leave, because in the three-dimensional ocean there are many directions for escape - all of them can be blocked only with an accurate understanding of the role and place of each of the attacking predators.

Hunting tricks of predators

Later, joint hunting of sharks and data about this phenomenon began to come from various sources - for example, off the coast of Seal Rocks in New South Wales (Australia), a diver observed the hunt.

A group of these predators drove young yellowtails (Seriola lalandi) onto the shallows and suppressed them with blows from their tail fins, creating a shock wave similar in strength to the consequences of a shot into the water from a large-caliber gun.

Also, sharks of the same species can - a fact established by scientists. Like a pride of lions heading out to hunt, predators coordinate their actions using non-verbal communication: certain positions of the fins and body; oscillatory waves generated by the caudal fin.

They are learning - scientists have repeatedly observed how sharks of the same species played “catch and take away”, where the role of the baton was played by a branch of algae.

Sharks also benefit from their ideally streamlined body shape - it is lighter and more mobile than the body of any other predator with a bony skeleton. This is precisely the ability of predators to move long distances with low energy costs.

Watch video - The secret of hunting a great white shark:

Shark is the perfect hunter

If other predatory fish are tied to a permanent habitat - long journeys are comparable for them to a hike through a waterless desert full of dangers, then sharks easily endure, figuratively speaking, the “hardships and hardships” of travel.

For information: ichthyologist Frank Carey (Woods Hall Institute of Oceanography) installed a sensor on a great white shark and, and movements for 4 months, came to an interesting conclusion - if a person had the metabolism of a shark, then he would only need to eat once in 1.5-2 months!

Finally, shark hunting is unique due to the shark clan - they are not something special among the marine fauna, because... some species of bony fish have similar receptors.

However, only sharks have perfected electroreception, hearing and smell, thanks to which predators easily detect the most accessible prey during the hunt, even in the pitch darkness of the depths of the sea.

All of the listed abilities of sharks give them superiority among other ocean creatures, ensuring many millions of years of existence in the past and successful fight against competing species in the present.

Anyone who still thinks that the biggest fish on the planet is blue is deeply mistaken. Whales are classified as mammals, and among them he is truly the very best. And here whale shark is the most largest living fish.

Description and features of the whale shark

This gigantic species was hidden from the eyes of ichthyologists for a long time and was discovered and described relatively recently - in 1928. Of course, even in ancient times there were rumors about a monster of unprecedented size living in the depths of the sea; many fishermen saw its outline through the thickness of the water.

But for the first time, a scientist from England, Andrew Smith, was lucky enough to see it with his own eyes; it was he who explained in detail to zoologists about its appearance and structure. A 4.5 meter long fish caught off the coast of Cape Town was named Rhincodon typus ( whale shark).

Most likely, the naturalist came across a teenager, since the average length of this underwater inhabitant ranges from 10-12 meters, whale shark weight– 12-14 tons. The most big whale shark, discovered at the end of the last century, weighed 34 tons and reached a length of 20 meters.

It got its name not for its impressive size, but for the structure of its jaw: its mouth is located strictly in the middle of the head, like in real whales, and not at all in the lower part, like in most of its shark relatives.

The whale shark is so different from its fellows that it is classified into a separate family, consisting of one genus and one species - Rhincodon typus. The massive body of the whale shark is covered with special protective scales, each such plate is hidden under the skin, and on the surface you can only notice razor-sharp tips, reminiscent of teeth in shape.

The scales are covered with an enamel-like substance called vitrodentin and are as strong as shark teeth. Such armor is called placoid and is present in all species. The skin of a whale shark can reach 14 cm in thickness. Subcutaneous fat layer – all 20 cm.

The length of a whale shark can exceed 10 meters

From the back, the whale shark is painted dark gray with bluish and brown streaks. Light whitish round spots are scattered across the dark main background. On the head, fins and tail they are smaller and chaotic, while on the back they are arranged in a beautiful geometric pattern of regular transverse stripes. Each shark has a unique pattern, similar to a human fingerprint. The gigantic shark belly is off-white or slightly yellowish in color.

The head has a flattened shape, especially towards the end of the snout. During feeding, the mouth opens wide, forming something like an oval. Whale shark teeth Many will be disappointed: the jaws are equipped with small teeth (up to 6 mm), but the number will surprise you - there are about 15 thousand of them!

On the sides of the mouth there are deep-set small eyes; in particularly large individuals the eyeballs do not exceed the size of a golf ball. Sharks do not know how to blink, however, if any large object approaches the eye, the fish pulls the eye inward and covers it with a special fold of skin.

Fun Fact: Whale Shark, like other representatives of the shark tribe, when there is a lack of oxygen in the water, it is capable of turning off part of its brain and hibernating to conserve energy and vitality. It is also curious that sharks do not feel pain: their body produces a special substance that blocks unpleasant sensations.

Whale shark lifestyle and habitat

Whale shark, dimensions which is due to the absence of natural enemies, slowly plows the expanses of the world's oceans at a speed of no more than 5 km/h. This majestic creature, like a submarine, slowly glides through the water, periodically opening its mouth to swallow food.

The pattern of spots on a whale shark is as unique as a human fingerprint.

Whale sharks are slow and apathetic creatures that show neither aggression nor interest. You can often find whale shark photo almost in an embrace with the diver: indeed, this species does not pose a danger to humans and allows you to swim close to itself, touch the body, or even ride while holding the dorsal fin.

The only thing that can happen is a blow from a powerful shark tail, which can, if not kill, then greatly injure. According to scientific research, whale sharks live in small groups, less often alone, but sometimes, in places where schooling fish gather seasonally, their number can reach up to hundreds.

So, off the coast of Yucatan in 2009, ichthyologists counted more than 400 individuals; such a cluster was caused by the abundance of freshly spawned eggs, which sharks feasted on.

Including whales, they must constantly be in motion, since they do not have a swim bladder. The muscles of the fins help the fish’s heart pump blood and maintain sufficient blood flow for life. They never sleep and can only sink to the bottom or hide in underwater caves to rest.

What helps sharks stay afloat is their huge liver, which is 60% fatty tissue. But this is not enough for the whale shark; it has to float to the surface and swallow air so as not to go to the bottom. The whale shark is a pelagic species, that is, living in the upper layers of the world's oceans. Usually it does not descend below a depth of 70 m, although it is capable of diving to 700 m.

Because of this feature, whale sharks often collide with large sea vessels, are maimed or even die. Sharks cannot stop or suddenly slow down, since in this case the flow of oxygen through the gills is minimal and the fish can suffocate.

Whale sharks are thermophilic. Surface waters in the places where they live are heated to 21-25°C. These titans will not be found north or south of the 40th parallel. This species is found in the Pacific, Indian and Atlantic oceans.

Whale sharks also have their favorite places: the east and southeast coasts, the Seychelles archipelago region, the island of Taiwan, the Gulf of Mexico, the Philippines, and the Australian coast. Scientists estimate that 20% of the world's population lives off the coast of Mozambique.

Whale shark feeding

It's paradoxical, but whale shark is not considered a predator in the usual sense. Despite its colossal dimensions, the whale shark does not attack other large animals or fish, but feeds on zooplankton and small fish that fall into its vast mouth. Sardines, anchovies, mackerel, krill, some types of mackerel, small tuna, squid and the so-called “live dust” - that’s the entire diet of this giant.

It's amazing to watch this giant feed. The shark opens its huge mouth wide open, the diameter of which can reach 1.5 meters, and captures sea water along with small living creatures. Then the mouth closes, the water is filtered and exits through the gill slits, and the strained food goes straight into the stomach.

It has a whole filtering apparatus, consisting of 20 cartilaginous plates that connect the gill arches, forming a kind of lattice. Small teeth help keep food in the mouth. This way of eating is not only whale shark: giant and largemouth also eat in a similar way.

The whale shark has a very narrow esophagus (about 10 cm in diameter). In order to push a sufficient amount of food through such a small hole, this huge fish has to spend about 7-8 hours a day getting food.

Shark gills pump about 6,000 m³ of fluid per hour. The whale shark cannot be called a glutton: it eats only 100-200 kg per day, which is only 0.6-1.3% of its own weight.

Reproduction and lifespan of the whale shark

For a long time there was almost no reliable data on how the whale shark reproduces. It has only recently begun to be successfully kept in captivity, in huge aquariums, where such giants have enough freedom.

Today there are only 140 of them in the world. Thanks to modern technologies that make it possible to create such grandiose structures, it has become possible to observe the life of these creatures and study their behavior.

Whale sharks are ovoviviparous cartilaginous fish. In my womb whale shark length 10-12 meters can simultaneously bear up to 300 embryos, which are enclosed in special capsules like eggs. The baby sharks hatch inside the female and are born into the world as completely independent and viable individuals. The length of a newborn whale shark is 40-60 cm.

At birth, the cubs have a fairly large supply of nutrients, which allows them to go without feeding for a long time. There is a known case when a still alive baby shark was pulled out of a harpooned shark and placed in a large aquarium: the baby survived, but began to eat only after 17 days. The gestation period of a whale shark, according to scientists, is about 2 years. During this period, the female leaves the group and wanders alone.

Ichthyologists are inclined to believe that whale sharks reach sexual maturity at a body length of 4.5 m (according to another version, from 8). The age at this point can be 30-50 years.

The lifespan of these giant sea inhabitants is about 70 years, some live 100. But individuals who have lived 150 years or more are still an exaggeration. Today, whale sharks are monitored, tagged with radio beacons and their migration routes are tracked. There are only about a thousand such “marked” individuals; it is unknown how many more are wandering in the depths.

About the whale shark, white or any other, you can talk for hours: each of them is a whole world, a small space and an immense universe. It is foolish to think that we know everything about them - their simplicity is apparent, and the accessibility of study is illusory. Having lived on Earth for millions of years, they are still full of secrets and never cease to amaze researchers.

Wondering if there are sharks in the Black Sea? And it’s not even about horror movies from childhood, but about the most common human concern for one’s life and health.

Are there sharks in the Black Sea?

The answer to such a question can instill fear in unknowing people, because this answer: "Yes", and this is a scientifically proven fact.

What predators live there?

You can breathe out - the sharks that live in the waters of the Black Sea are practically not dangerous for humans due to its small size and caution. During the day they hide in the depths and do not disturb vacationers with their presence.

When meeting fishermen, Black Sea sharks do not attack them, but go to the bottom.

In addition to sharks, there are other dangerous ones in the Black Sea:

Jellyfish. Cornerot is dangerous; it can sting a person quite seriously with its poison;
Sea ruff or scorpionfish. It has clawed teeth and poisonous glands located on its fins;
Sea dragon. The seemingly harmless fish has poisonous glands next to the spine on the gill cover and on the first dorsal fin, which poses a great danger to people;
Stingray stingray. Its tail has a sharp spine that can grow up to 35 cm. The sting of this protective element is very painful.

Unfavorable living environment

The Black Sea is unfavorable for the life of large sharks that are dangerous to humans for a number of reasons. At a depth of approximately 60-70 meters, the Black Sea waters contain hydrogen sulfide, which is not suitable for breathing for most shark species.

And one more fact why there are no dangerous sharks in the Black Sea. Due to the lack of diversity and quantity of marine fauna, large predators simply nothing to eat in the Black Sea. The slightly salty waters of the Black Sea are not suitable for the life of large sharks that got into it from.

Black Sea species of thunderstorms of the seas - photo

Only two shark species

Katran

Also called dogfish or the Black Sea shark is the most famous predator of the Black Sea. The main feature of this shark is the spines on its fins, which are designed for protection. They are covered with poisonous mucus. There are known cases when a person could be injured by this shark while sorting the catch, being injured by poisonous spines.

Katrans do not like to swim alone and prefer to flock together in common schools.

The katran has a streamlined elongated shape, this allows you to develop higher speed. These sharks live at a depth of up to 40 meters, a little deeper in the summer, as they prefer water with a temperature of 14-15 degrees. An adult katran is no more than 160 cm in length and lives 25 years. It prefers to eat herring, horse mackerel, squid and even octopus. Avoids meeting people.

Feline

Cat shark is also known as scyllium. It has a fairly small size - on average 60-70 cm. The shark's body is covered with spots, which makes it similar to representatives of the feline species. Hunts in shallow water, feeding on small fish and crustaceans. Due to its size, it is often included in the diet of its larger counterparts. It usually lives at a depth of 80-100 meters.

This nocturnal predator has excellent vision darkness. During the day he prefers to lead a sedentary lifestyle. This species of shark mainly lives along the coast of the Atlantic Ocean and in the Mediterranean Sea, from where it enters the Black Sea through the Bosphorus during the migration period.

Blue, spiny and dwarf sharks can be found in the waters of the Adriatic Sea. Where is it - read in.

Sea killers and cases of attacks on people

Most of the claims that there are dangerous sharks in the Black Sea are related to fishing stories. And they are among the most mysterious and dangerous species of sharks in the World Ocean.

Goblin Shark

Differently goblin shark. Perhaps the most ancient and little-studied species of shark on the planet. The only deep sea shark. Scientists have come across the bones of a goblin shark that is 80 million years old.

This fish acquired such an ominous name for a reason. The goblin has a large sensitive protuberance on its nose, which does not add to its attractiveness, and a movable jaw that moves far forward when it sees prey. It prefers depths of more than 300 meters and never rises to the surface. There are enough rarely and was considered an extinct species for many years.

Compared to the Black Sea sharks, the goblin has an impressive size. The length of an adult is more than 3 meters.

Even the color of this shark remains a mystery; it is supposedly pink, but if the shark dies, it changes to brown.

The shark has interesting features:

Electroreception. That is, it is able to perceive electrical impulses from the environment. This helps her get food in the dark depths of the sea;
She has another ability of deep-sea fish - her eyes. glow in the dark greenish light.

The goblin feeds on shellfish and fish. Shark lives in all oceans except for the Arctic, preferring warm and temperate waters. Most often found off the coast of Japan.

In December 2010, information appeared in the media that in the Black Sea in the area, fishermen was caught goblin shark. No one was hurt except the shark itself. Photos, video reports, interviews appeared. However, experts considered the information a “duck”. It is also not known how dangerous the goblin shark actually is.

White torpedo

Shark eater. The name speaks for itself. This is one of the largest predators on the planet. Its length reaches 7 meters. Despite its enormous size, the shark is quite intelligent and curious; it has a well-developed sense of smell, allowing it to smell prey several kilometers away.

The shape of a shark resembles torpedo, which allows it to reach speeds of up to 24 kilometers per hour. Can dive to depths of more than 1000 meters. White sharks live 60 years. Adults feed on large fish, seals, sea lions, cephalopods, and can attack other sharks and even whales.

The great white shark has gained a reputation as a killer due to numerous cases of attacks on humans. This shark lives in the Pacific, Atlantic and Indian oceans.

According to scientists, the entry of white sharks from the Mediterranean Sea through the Bosphorus is quite probably, but they will not swim far from the strait and the shores - changes in water temperature in winter and summer are not suitable for them.

White sharks are thermophilic - they live in waters heated from +12 to +24 degrees.

Here are some cases of white sharks appearing near the Black Sea from the world of news:

V 2008 And 2009 years, in the area of the Dardanelles Strait, fishermen from Turkey caught baby white sharks in a net;
in July 2011 year, Turkish fishermen caught a young great white shark in the same region;
in September 2016 the same fishermen discovered a school of white sharks in the Bosphorus Strait off the coast.

Blue sea queen

This species of shark got its name because of its unusual gray-blue color. Smaller in size than white, adults reach 4 meters. This species lives in the Indian and Pacific oceans. Prefers moderate and calm waters.

The blue shark is an excellent hunter; it loves small fish; in coastal waters it can attack waterfowl. This fish does not distinguish colors, but has phenomenal sense of smell.

The blue shark has a complex relationship with humans. In Malaysia, the blue shark is a commercial fish and it is from there that it ends up on the tables of gourmets in different countries. But the predator herself does not remain in debt. Probability of attack especially large in the open ocean.

Less commonly, careless swimmers in warm lagoons can also be attacked by blue sharks.

On April 12, 2015, a blue shark attacked a photographer in south Florida, resulting in only a bitten forearm. According to the victim, he himself provoked shark in pursuit of the perfect shot.

And in this video you can find out a little more about one of the Black Sea sharks:

The existence of the species is approximately 420–450 million years. Over such a long time, many legends and legends have developed about the sea predator. The formidable animal began to be studied in detail during the Patriotic War, during the fighting in the Indian and Pacific oceans.

There are 400 different species from the smallest to the giants. However, they can be clearly opposite to each other. Thanks to Hollywood films, we know about the bloodthirstiness of this animal and the ability to smell blood from many kilometers away. But in fact, shark species are still very little studied. And not all of them are aggressive.

Shark - mammal or fish

Mammals are animals that feed their offspring with milk. But our predator does not do this and, moreover, breathes with gills. Shark is a fish.

The shark is a complex and unique organism. Over many years of adapting to changing habitat conditions, she has become a perfect hunter. Excellent hearing, vision, sense of smell, and size make her a truly terrifying creature. During the study by specialists of this species, similarities were discovered between bony fish and animals.

Main differences between fish and mammals

Fish have no milk. Mammals feed their young with milk.
Caring for offspring. The predator produces genetically strong offspring that do not require care or training in food extraction skills. The little storm of the seas knows how to hunt and distinguishes enemies from friends.
The shark is always on the move and practically never sleeps.
The largest number of sense organs.

The habitat of sharks is the salty waters of the seas. There are varieties of freshwater sharks. In depth they rarely go deeper than two thousand meters.

Anatomy and physiology of an underwater predator

The peculiar structure distinguishes the shark from many inhabitants of the seas and oceans. There are no bones in the skeleton of this individual. They are replaced by cartilage. Due to the high calcium content in the shark's body, the cartilage is quite strong.

The shape of the body, like a torpedo, indicates the speed of the fish. Speed approximately 8 km/h. In pursuit of prey, it can reach 19 km/h. The fastest shark - mako reaches a speed of 50 km/h.

The head is quite large. The skull is a cartilaginous box. The eye sockets are located on the sides and the brain is located between them. The scales are diamond-shaped with a spike at the end. The surface resembles sandpaper.

The mouth is wide. The mouth is located at the bottom of the head. The jaws are equipped with several rows of teeth. They fall out as they wear and grow into the next row of teeth. One of the most toothy fish. The structure and shape of each subspecies differs. In deep-sea fish they are flat with an uneven surface. Sharp and long for predators. In the largest individuals they are large, wide and jagged. Planktonic ones have small and small 3–5 mm.

Gill slits are located behind the head. Oxygen is supplied by the passage of water through the gills.

The swim bladder allows fish to float on the surface of the water. Sharks don't have it. Buoyancy is provided by a large liver, fins and a cartilaginous skeleton. They have to constantly be on the move in order to be able to breathe, and therefore they hardly sleep. Experts believe that some species of sharks sleep like dolphins, with one eye watching what is happening.

The caudal fin has its own characteristic features. Symmetrical or asymmetrical. The fin of most has an asymmetrical shape, with most of it pointing upward.

Numerous experiments by specialists have confirmed the sensitivity of sharks to odors. By smell, the predator obtains food and finds a partner. Most often they react to the smell of blood and restless behavior of the prey. 14% of the brain is involved in information processing. The smell is captured not only in water, but also in the air. To do this, it raises its muzzle to the surface of the water. Dissolved blood smells in a ratio of 1:1000000.

Vision. The structure of the eye has certain features that allow it to see in poorly lit places. The blinking eyelid, which protects the eye, is another structural feature. The eyelid closes during attacks on the victim. Sharks without eyelids roll their eyes when attacking.

The inner ear allows some shark species to hear infrasound. It also serves for balance.

An exceptional property is electroreception. Allows you to navigate the terrain. The ability to recognize electrical and magnetic signals allows you to quickly and accurately find food and communicate with your own kind.

Reproduction

Although a shark is a fish, it does not spawn like most fish. There are three types of offspring:

Viviparous. Embryo development occurs inside the body. Quite independent creatures are born.
Oviparous. Lays several eggs packed in capsules that can support the life of the embryo for a long time.
Ovoviviparous. Gestation inside the body.

A distinctive feature of the offspring is their adaptability to life from the first days of existence..

Nutrition depends on the habitat and type of animal. Most are carnivores or omnivores. The food is fish, crustaceans, mammals or plankton. After a hearty lunch, she goes without food for a long time.

Scientists note an average life expectancy of 20 or 30 years. The longest-lived spotted spiny sharks live up to 100 years.

Sharks have a bad reputation due to misinformation. However, you will come to appreciate these fish once you learn the basic facts about shark life.

Approximately 465 known shark species live in the oceans today

It is difficult to estimate the population size of each shark species individually because each species' range covers such a large geographic area. But the total number of sharks in the wild is constantly declining.

While many of us are afraid of sharks, we need to know that Man is the largest predator on the planet. People are scarier than sharks. In fact, humans kill more than 73 million sharks every year.

On average, 30 to 50 shark attacks are reported annually, only 5 to 10 of these attacks are fatal to humans. The chances of dying from a shark attack are much lower than the chances of dying from a hornet, wasp, bee or dog attack. You may think of sharks as terrifying, man-eating predators, but in reality, only 3% of sharks—a small minority—are dangerous to humans.

Sharks are the predecessors of dinosaurs. They are 200 million years older than dinosaurs. Moreover, over 450 million years (the geological age of sharks), these ancient representatives of the fauna have not changed at all.

Sharks are the top of the food chain - they are the top predators of the sea and regulate the populations of all species.

Recent studies have shown that there is a massive depletion of sharks. This has cascading consequences for changes in the entire ocean ecosystem.

Sharks are fish

Sharks belong to the family of cartilaginous fish. The difference between cartilaginous fish and bony fish is that the cartilage skeleton is lighter and more flexible.

Sharks breathe through a series of gill slits, with 5-7 gill slits located on either side of their body.

All sharks have several rows of teeth. They lose teeth on a regular basis, but new teeth continue to grow and replace the lost ones.

When a shark dies, the salt of the seawater completely dissolves its skeleton, leaving only its teeth.

Shark skin" consists of a series of scales that act as an outer frame for easy movement in the water. The top side of the shark is usually dark to blend in with the water and is not visible from above. And their lower part is white, in harmony with the lighter surface of the sea below. This helps sharks camouflage themselves.

Sharks have a very keen sense of smell, capable of detecting blood in the water from several miles away.

Sharks' eyes have a surprisingly wide field of view, covering almost 360 degrees. Their panoramic view of the underwater world is hindered only by two blind spots, one in front of the snout and the other directly behind the head.

Sharks are adapted to life in a wide range of different aquatic temperatures.

Some species live in shallow, coastal areas, other species live in deep waters on the ocean floor, and others live on the surface in the open ocean.

The goblin shark lives along outer continental shelves and underwater ridges. Their dwellings are too deep for people, so we know almost nothing about them.

Some species, such as the bull shark, are able to live in both salt and fresh water.

Most sharks are active in the evening and at night - this is their hunting time.

Sharks are capable of migrating long distances—on a scale that can cross entire ocean basins.

There are solitary species of sharks, and there are social ones - preferring to live in groups.

How do sharks feed and what do they eat?

Some shark species, such as the great white shark, attack from below. As a rule, their prey is seals and sea lions.
Species of sharks that live on the ocean floor have developed the ability to collect bottom food.
There are species of sharks that attack schooling fish.
Large and basking sharks feed like whales, filtering ocean water through their wide-open mouths. During filtration, large quantities of plankton and krill are ingested.

Shark Facts You Should Know

Sharks mature slowly, reaching reproductive age at 12 to 15 years. And a whale shark can reproduce its first offspring only after reaching the age of 30 years. This, combined with the fact that many species only give birth to one or two young, means that sharks have great difficulty recovering. That's why their population has declined so much.

The gestation period of a shark lasts from 5 months to 2 years, depending on the type of shark. Some female sharks use sperm from multiple males to create a single litter.

Soon after birth, the baby sharks, while still puppies, swim away from their mother. They are able to stand up for themselves from birth. Baby sharks are born with a full set of teeth and are able to feed and live independently.

All sharks are characterized by cannibalism. At the same time, not only adults are cannibals; prenatal cannibalism is exhibited by baby sharks, feeding on the eggs of fellow sharks, which the female produces during pregnancy. That’s why out of a litter of 80 eggs, only 1-2 baby sharks are born.

Sharks that eat the eggs of their siblings in the womb are not vicious. They are simply looking for nutrients to support themselves as they grow.

A baby shark is a miniature copy of its parents. The photo shows tiger sharks.

The largest known extinct shark species, Megalodon, reached a maximum length of 20 meters (67 ft).

Of the living creatures, the largest is the gigantic whale shark. It can reach a body length of 15 meters.

TOP smallest sharks:

Dwarf spiny shark (Squaliolus laticaudus) - the usual body length is 15-20 cm, and the maximum is 24 cm.
The dwarf glow shark (Euprotomicrus bispinatus) is a fish 20-25 cm long.
Longnose shark (Heteroscymnoides marleyi) is a small fish, 12.5-30 cm long.
Lighttail shark (Euprotomicroides zantedexchia) - maximum length 20 cm.
Cuban marten shark (Triakidae barbouri) - maximum 35-40 cm.

Glowing shark - record holder of minimalism

Some known shark species drown if they stop moving. They do not have a swim bladder, so they must swim all the time - they expend a lot of energy in movement. Compare. A great white shark needs 11 tons of food every year! And a human being eats half a ton of food a year.

The great white shark (Carcharodon carcharias), Mako (blacktip, mackerel, blue-gray) shark and Salmon sharks (Lamna ditropis) of the herring family - do not have muscles, they pump water through the mouth and gills. They keep their mouths open the entire time they swim, this keeps them alive.

Sharks have large livers. Shark livers contain a lot of oil. This makes the liver a relatively buoyant organ, helping sharks maintain balance in the water.

Poking a shark in the nose or eyes to fend off their attack does not help. It’s better to hit them in the gills (these are large slits along the snout) - this tactic works much more effectively against sharks. Most sharks swim away when their target is difficult to reach for their food. You are more likely to die from drowning than from a shark attack. This is true.

Tiger sharks, great white sharks and bull sharks (blunt-nosed bull sharks) generally attack people from behind. Their prey is anything that is human-sized. They are strong enough to attack and deliver a fatal bite.

In the extremely rare event that a shark bites you, it most likely will not attempt a second bite. When attacking people, sharks usually hold them for a few seconds and then release them once they realize that what they have tasted is not a sea creature.

20-30 percent of sharks are critically endangered. The main culprit is industrial fishing, where sharks are accidentally caught on hooks and nets. And due to the excessive popularity of shark fins (commercial demand), the populations of some shark species have declined by approximately 90%.

The blue shark (Prionace glauca) is considered the rarest shark species.

Another rare species is the frilled shark Chlamydoselachus anguineus. They are often called living fossil sharks. They live at great ocean depths of 1000-1500 meters.

Shark eggs are very different in appearance from those eggs laid by birds, lizards or crocodiles. They are often protected by capsules or leathery pouches. In the case of the horn shark, they are called "mermaid purses."

Contrary to popular belief, sharks are not colorblind; they are good at distinguishing colors. Divers claim that sharks are attracted to certain colors - yellow, the color of some wetsuits, is a "yummy" color for them. While shark color preferences have not been proven, scientists do know that sharks living in a well-lit aquarium exhibit color discrimination, which humans use as cues.

Angel sharks, also known as sand devils (Squatina), burrow into piles of sand. From there they lie in wait, waiting for unsuspecting fish.

Scientists have discovered a sleeping species of shark near Mexico (from among the reef sharks), which are able to lie motionless.
Sharks come in different shapes, some of which are quite bizarre. For example, this is what a Hammerhead Shark looks like.