Hammer fish description for kids. Hammerfish: description and interesting facts

Hammer-reducer Hammer-reducer is a mechanism consisting of a gear reducer and a hammer, made in the form of a slider, moving along the guides. The input link of the hammer-reducer is coaxial with the output link. The drive of this mechanism is carried out from an asynchronous

Pile Hammer A pile hammer is a percussion construction machine designed to drive piles into the ground. There are three types of pile hammers: 1) mechanical (the load is lifted with a winch, and then released, while the head is hit

When meeting with a hammerhead shark, you should not consider this amazing creature for a long time. The outrageousness of her exterior is directly proportional unmotivated aggression shown in relation to a person. They saw a “sledgehammer” floating at you - hide.

Strange head shape

Thanks to her, you will never confuse the hammerhead shark (lat. Sphyrnidae) with another inhabitant sea ​​depths. Her head (with huge outgrowths on the sides) is flattened and divided into two parts.

The ancestors of hammerhead sharks, as shown by DNA analyzes, appeared about 20 million years ago. Investigating DNA, biologists came to the conclusion that the most typical representative of the Sphyrnidae family should be considered a large-headed hammerhead fish. It stands out from other sharks with the most impressive head outgrowths, the origin of which they try to explain with two polar versions.

Proponents of the first hypothesis are sure that the head acquired its hammer-shaped shape over several million years. Opponents insist that the bizarre shape of the shark's head arose as a result of a sharp mutation. Be that as it may, this marine predators I had to take into account the specifics of their outlandish appearance when choosing prey and lifestyle.

Types of hammerhead sharks

The family (from the class of cartilaginous fish) called hammerhead fish or hammerhead shark is quite extensive and includes 9 species:

• Common hammerhead shark.
• Large-headed hammerhead fish.
• West African hammerhead.
• Round-headed hammerhead fish.
• Bronze hammer fish.
• Small-headed hammerhead fish (shovel shark).
• Panamo-Caribbean hammerhead fish.
• small-eyed giant shark-hammer.

The latter is considered extremely ferocious, agile and fast, making it the most dangerous. It differs from its relatives in its enlarged size, as well as in the configuration of the front edge of the “hammer”, which has a straight shape.

Giant hammerhead fish grow up to 4-6 meters, but specimens approaching 8 meters have sometimes been caught..

These most formidable predators for humans and other representatives of the Sphyrnidae family have taken root in the tropical and warm-temperate waters of the Pacific, Atlantic and Indian oceans.

This is interesting! Sharks (mostly females) often gather in groups in underwater rocks. An increased mass character is noted at noon, and at night the predators leave until the next day.

Hammerhead fish have been observed both on the surface of the ocean and at a fairly large depth (up to 400 m). They prefer coral reefs, often swim in lagoons and frighten vacationers in coastal waters.

But the largest concentration of these predators is noted near the Hawaiian Islands. It is not surprising that it is here, at the Hawaiian Institute of Marine Biology, that the most serious scientific research dedicated to hammerhead sharks.

Description

Lateral outgrowths increase the area of ​​the head, the skin of which is dotted with sensory cells that help to pick up signals from a living object. The shark is able to catch very weak electrical impulses emanating from the bottom of the sea: even a layer of sand, where its victim will try to hide, will not become an obstacle.

A theory has recently been debunked that the shape of the head helps the hammerhead fish to maintain balance during sharp turns. It turned out that the stability of the shark gives arranged in a special way spine.

On the lateral outgrowths (opposite each other) are large rounded eyes, the iris of which is colored golden yellow. The organs of vision are protected by eyelids and supplemented by a nictitating membrane. The non-standard location of the shark's eyes contributes to a full (360 degrees) coverage of space: the predator sees everything that happens in front, under and above it.

With such powerful enemy detection systems (sensory and visual), the shark does not leave him the slightest chance of salvation. At the end of the hunt, the predator presents its last “argument” - a mouth with a row of smooth sharp teeth.. By the way, the giant hammerhead shark has the most terrible teeth: they are triangular, inclined to the corners of the mouth and equipped with visible notches.

This is interesting! A hammerhead fish, even in the darkest darkness, will never confuse north with south, or west with east. Maybe she picks up a magnetic field the globe which helps her stay on track.

The body (against the background of the head) is unremarkable: it resembles a huge spindle - dark gray (brown) above and off-white below.

reproduction

Hammerhead sharks are classified as viviparous fish. The male performs sexual intercourse in a very peculiar way, piercing his partner with his teeth.

Pregnancy, which occurs after successful mating, lasts 11 months, after which from 20 to 55 perfectly swimming babies (40-50 cm in length) are born. So that the female is not injured during childbirth, the heads of the born sharks are turned not across, but along the body.

Having got out of the mother's womb, the sharks begin to actively move. Reaction speed and maneuverability save them from potential enemies, which often become other sharks.

Hammerhead prey

Hammerhead sharks love to indulge in seafood such as:

• octopus and squid;
• lobsters and crabs;
• sardines, horse mackerel and sea catfish;
• crucian carp and sea bass;
• flounder, fish-urchins and fish-toads;
• sea ​​cats and croakers;
• mustelid sharks and gray sharks.

But the hammerhead shark has the greatest gastronomic interest.. The predator goes hunting at dawn or after sunset: in search of prey, the shark approaches the bottom and swings its head to raise the stingray.

Having found the prey, the shark stuns it with a head blow, after which it holds it with the help of a “hammer” and bites so that the stingray loses its ability to resist. Then she tears the stingray into pieces, capturing it with her sharp mouth.

Hammerhead fish quietly carry toxic stingray spines left over from their meal. Once, a shark was caught off the coast of Florida with 96 of these spikes in its mouth. In the same area, giant hammerhead sharks (led by their keen sense of smell) often become a trophy for local fishermen, pouncing on baited hooks.

This is interesting! Currently, biologists have recorded about 10 signals that hammerhead sharks exchange when gathering in flocks. Scientists have proven that some of the signals serve as a warning: the rest have not yet been deciphered.

Man and hammerhead shark

Only in the Hawaiian Islands, sharks are equated with sea deities that protect people and regulate the number of ocean fauna. Aborigines believe that the souls of their dead relatives move into sharks, and sharks with hammerheads are shown the greatest respect.

Paradoxically, it is Hawaii that annually replenishes the reports of sad incidents related to the attacks of hammerhead sharks on humans. This is explained quite simply: the predator enters shallow water (where tourists swim) to breed. At this time, hammerhead fish are especially excited and aggressive.

A priori, a shark does not see its prey in a person, and therefore does not specifically hunt him. But, alas, these predatory fish have a very unpredictable disposition, which in an instant can push them to attack.

If you accidentally run into this sharp-toothed creature, remember that sudden movements (swinging arms and legs, quick turns) are absolutely prohibited. You need to swim away from the shark up and very slowly, trying not to attract its attention.

Of the 9 species of hammerhead sharks, only three are recognized as dangerous to humans:

• giant hammerhead shark;
• bronze hammer fish;
• common hammerhead shark.

The remains of human bodies were found more than once in their ripped bellies.

However, biologists believe that undeclared war between hammerhead sharks and civilized humanity, humans win by a wide margin.

In order for patients to be treated with shark oil, and gourmets to enjoy shark meat dishes, including the famous fin soup, their owners are exterminated by the thousands. In the name of profit, fishing companies do not comply with any quotas and norms, which is why the number certain types Sphyrnidae has been frighteningly reduced.

The risk group included, in particular, the large-headed hammerhead fish. She, along with two other quantitatively decreasing related species, was called "vulnerable" by the International Union for Conservation of Nature and introduced into a special Appendix regulating the rules of fishing and trade.

Giant fish are not uncommon in modern time. The hammerhead shark is considered one of them, since its body length can reach 6 m. It lives in warm ocean waters and prefers tropical climate. The front front edge of this animal is straight, and the dorsal fin is crescent-shaped. The fish leads a solitary lifestyle and preys on cartilaginous and cephalopod fish.

The hammerhead shark is a large-sized fish that leads a solitary lifestyle.

shark classification

The hammerhead family includes several main species. Classical representatives are ordinary and big-headed . The list also includes sharks:

• West African;
• large-headed;
• bronze;
• Panamanian;
• Caribbean;
• gigantic.

The giant hammerhead shark is considered the most aggressive, fast and maneuverable due to which it poses a great danger to its neighbors. sea ​​waters. The length of her body varies from 4 to 6 m, but some specimens reach 8 m. Predators were able to take root well in warm waters Atlantic and Pacific Oceans. They prefer to stay in packs. You can find them near underwater rocks. The largest groups gather at noon, and at night they part until the next morning.

The giant hammerhead shark is considered the most aggressive, fast and maneuverable.

It is noteworthy that predators can live both at an impressive depth and at the very surface of the water. They love coral reefs, sometimes they allow themselves to swim into the lagoon and scare people walking nearby. The largest concentration of predators is concentrated near the Hawaiian Islands. Nearby is the Institute of Marine Biology, where important Scientific research dedicated to hammerhead fish.

External signs

The head has lateral outgrowths. Their entire area is covered with especially sensitive cells. They are necessary for the shark to receive signals from nearby living organisms. Even a rather weak impulse can be caught by a predator without any problems. A layer of sand is not a serious obstacle for her, and therefore the victim cannot hide in its thickness. Until recently, it was believed that the unusual shape of the head is designed to maintain the balance of the fish. But it turned out that this stability is ensured by the special shape of the spine.

Lateral growths are located opposite each other. Here are located big eyes round shape. Their features:

• golden color of the iris;
• the presence of the nictitating membrane and eyelids;
• non-standard location, due to which the predator has a 350-degree view.

We can say that this animal has everything necessary tools to locate the enemy. They are visual and sensory. In counteraction with the enemy, the hammerhead shark also uses sharp, smooth teeth. They have a triangular shape, are distinguished by a peculiar slope and invisible notches.

Hammerhead shark - fish, well oriented in space fish. She manages to capture the Earth's magnetic field in an amazing way, so the fish does not stray from the intended course. The body is dark gray or brown above and white below.

Reproduction features

These are viviparous fish. During mating, the male bites his teeth into the partner's body. It takes 11 months to bear a cub. Usually, from 20 to 55 babies are born from 40 to 50 cm long. Nature made sure that the female did not get injured during childbirth. For this, the head of the cubs is located not across, but along the body. As soon as they get out of the womb, the fish begin to move actively. Maneuverability and responsiveness allow them to escape from possible enemies. Often their role is performed by other sharks.

What does a predator eat

Hammerhead sharks like to feast on squid, crab and octopus. Also, their diet consists of:

• sea ​​bass;
• dark gray sharks;
• hedgehog fish;
• croaker;
• crucian carp;
• horse mackerel.

But the most favorite type of food for them are stingrays. To catch prey, the predator leaves its lair in the morning or after sunset. At this time, he swims at the very bottom and waves his head. He does this on purpose to stir up the stingray. Having found the victim, the shark strikes its head on its body. This is followed by a bite, depriving the ability to resist.

The shark tears the stingray apart. Surprisingly, the toxic spikes that cover the body of these creatures do not pose a danger to sharks. Once, a shark was discovered near the coast of Florida, which had about 90 such spikes in its mouth. Often these fish become the prey of local fishermen, as they fall on baited hooks.

An interesting fact is that the hammerhead shark is able to exchange signals with its fellows. It conveys information about 10 different situations that can take place. Most often these are warning signs.

Relationship with a person

In Hawaii, sharks are held in high esteem, they are treated almost like deities. Aborigines believe that hammerhead fish protect people and creatures inhabiting the ocean waters. Some even think that the souls of deceased relatives live in these fish. But, sadly, it is here, on the islands, that cases of shark attacks on humans are most often recorded. Most of all goes to tourists who like to swim in shallow water.

The fact is that it is here that female fish breed their offspring. During this period, individuals can be quite aggressive.

For a human, a hammerhead shark is not dangerous if it does not violate its boundaries and does not pose a threat to its offspring. She does not see a source of food in a person, and therefore she will never specifically attack him. However, her character is unpredictable, and therefore any action can push her to attack. Experts say to avoid:

• sharp swings of the legs and arms;
• quick turns to the side.

For a human, a hammerhead shark is not dangerous if it does not violate its boundaries and does not pose a threat to offspring.

If you have to swim away from a predator, you need to do it very slowly and in an upward direction. This way you won't attract the attention of a predator. The most dangerous varieties today are:

• gigantic;
• ordinary;
• bronze.

In a fight between sharks and humans, the latter often wins. People have learned how to extract shark fat, which is used to treat diseases. Gourmets love to eat these fish, including the world-famous fin soup.

Often this leads to the fact that animals are exterminated by the thousands. Bighead hammerheads are at risk for this reason. It has been declared an endangered species.

The common hammerhead shark belongs to the family of hammerhead sharks, like the rest of its relatives. It was first described in 1758 by Carl Linnaeus, a famous naturalist from Sweden. It is also called the smooth hammerhead shark or common hammerhead fish.

Smooth - because it does not have a depression characteristic of other species in the outer edge of the "hammer", because of which it resembles a bow in shape. Currently, eight species of hammerhead sharks are known to science, these are hammerhead fish - round-headed, West African, Panama-Caribbean, bronze and small-headed, as well as hammerhead sharks - giant, small-eyed giant and ordinary.

The giant hammerhead shark Sphyrna mokarran is found in the tropical waters of the Pacific, Atlantic and Indian oceans, but does not reach large numbers, its length reaches six meters.

The small-eyed giant shark Scalloped Hammerhead is found in the East and West Atlantic, the Pacific and Indian Oceans, its length does not exceed 4.5 meters. The common hammerhead shark is similar to the giant shark in almost everything except for the length.

Of the entire family, this species has the widest range of habitat - it can be found in almost all oceans, except for the Arctic Ocean and the waters of the tropical zone. It is difficult to determine the exact boundaries of the habitat of the hammerhead shark due to its strong resemblance to other species of hammerhead sharks.

It, as a rule, keeps closer to the surface at a depth of less than twenty meters - but cases of meeting it at depths of up to 200m have been recorded. This kind is more like coastal waters, but it can also be found in the open ocean, and even sometimes in fresh waters rec.

In summer, the hammerhead shark has its season of migration to the poles, where it is cooler, and in winter it returns to the equator again.

This is the second largest hammerhead shark - in the first place is the giant hammerhead shark. The length of an ordinary hammerhead shark is within 3.5 m. The largest length of this species met by people is 5 m, and its weight is 400 kg.

It is distinguished from other hammerhead sharks by the shape of the head - its “hammer” is curved along the front edge, and there is no notch in the center, it is rather wide and short, making up about 29% of the body length in diameter.

The "hammerhead" is actually its large and flat nose, on which the nostrils are located - closer to the edges of the "hammer", from them there are long grooves along the entire edge straight to the center - they help the hammerhead fish to capture odors. Scientists believe that the shark uses this "hammer" as a steering wheel.

Her eyes are located on the sides of the "hammer", they are large, golden yellow and protected by eyelids. Five small gill slits, the last being above the pectoral fin.

Up to 32 tooth rows in the upper jaw and up to 30 tooth rows in the lower jaw. The teeth are triangular in shape, beveled to the corners of the mouth. The body of the shark is streamlined, the body is covered with placoid scales with sharp edges, like most sharks. The skin color is dark brown or olive, the belly is white.

Fin tips may be darker. The pectoral fins and the first dorsal are strongly pointed. There are two dorsal fins in total - a large triangular first dorsal fin is located immediately behind the pectoral, and the second dorsal fin is relatively small and has a sharp, as it were, elongated posterior edge.

The anal fin is slightly larger than the second dorsal fin. triangular pectoral fins are 2/3 of the head of a hammerhead shark in length. Her body is slender, spindle-shaped and very flexible. The hammerhead shark is an excellent swimmer, it can develop considerable speed and maneuvers perfectly.

As a rule, the common hammerhead shark lives alone or in small flocks. During migration, they can gather in large numbers - up to hundreds and even thousands of individuals. Their young are preyed upon by larger sharks, such as the dark shark Carcharhinus obscurus. And in the waters of New Zealand, adults can become the object of attack by a flock of killer whales.

The hammerhead fish, or common hammerhead shark, is a very active predator. The diet of her diet is very diverse - stingrays, bony fish and sharks, even relatives, and at worst cephalopods, crabs and shrimps. Flounder and stingrays are her favorite delicacy, because most of all she prefers the muddy bottom.

Its prey will not be saved by burrowing into the mud - after all, with its unusual head, the hammerhead shark captures the electric fields that its victims generate - sometimes it rushes to the seemingly empty ground and triumphantly pulls out its prey.

Even stingray scans do not frighten her; many of their poisonous spikes are found in the stomachs of hammerhead sharks. Most likely, the common hammerhead shark has a strong immunity against the venom of stingrays, which allows it to freely eat them. She is also not afraid of her relatives and larger sharks, and on occasion she will devour them too.

The hammerhead shark is a viviparous, in its litter there can be from 20 or more sharks. Pregnancy lasts up to 11 months, newborns can be up to 61cm long. Embryos are connected to the mother's body through the placenta. Females become sexually mature when they reach a length of 2.7 meters, and males - 2.1-2.5 meters.

The life span of an ordinary hammerhead shark is from 20 years. This is one of the oldest fish on the planet, according to scientists, this species has existed for about 25 million years. In terms of numbers, it overtakes many other types of hammerhead sharks. Her look is intimidating. Everyone who has seen her thinks she is scary fish in the ocean. Its description can be found on the pages of Jules Verne's novels.

This shark is potentially dangerous to humans, among the most dangerous predators it ranks third - after the white and tiger sharks. Cases of hammerhead shark attacks on humans have been recorded, some fatal, and a human body was found in the stomach of one of them. As a rule, attacks increase during the breeding season, because for this she goes to coastal waters, so loved by bathers, popular beach places.

Therefore, in no case should you enter the water if the beach is not fenced with anti-shark nets. Another reason for shark aggression can be hunger - if suddenly her favorite food disappeared in her usual habitat, she may well replace it with a person.

With the end of the breeding season, cases of attacks by hammerhead sharks on humans become extremely rare. In short, you need to try very hard to have a hammerhead shark attack you. However, experts believe that any shark longer than a meter is dangerous to humans.

Sharks smell blood in their clothes, even in the smallest concentration. According to official statistics, from 40 to 300 people die every year from the attacks of all large sharks. What proportion of this number are those who died from the common hammerhead shark, it is impossible to say for sure.

If suddenly, being at a depth, you find a hammerhead shark nearby, try not to move, not to flounder and not to wave your arms and legs so as not to attract its attention - wait for help or slowly swim out into coastal waters. Try not to touch the shark's body - you can easily get hurt on the scales covering its skin, and then it will definitely show interest in you, smelling your blood. Be as careful as possible - then you will have a pretty good chance of staying alive.

But the common hammerhead shark itself is an object of commercial fishing around the world for humans. Shark meat is dried, smoked and salted, but it is of little value, there are cases of poisoning with it. But its fins are ranked number one in the ranking for making shark fin soup.

Therefore, most often hunting for hammerhead sharks is barbaric in nature - they are caught, their fins cut off and thrown back into the water to die. Shark oil is added to vitamins, the skin is dressed, and the by-products are suitable for the production of fishmeal. The hammerhead shark is widely used to make all kinds of medicines in Chinese medicine.

According to the classification of the International Union for Conservation of Nature, this species of hammerhead sharks is "vulnerable", and it is listed with this status in the Red Book. In many countries, the catching of these fish for the purpose of obtaining fins is already prohibited, and in New Zealand, hunting for them is generally under a complete ban.