One of the features of shark reproduction that distinguishes them from bony fish, is internal fertilization. The male fertilizes the egg directly in the female's body, introducing the genital organs - pterygopodia - into her cloaca. Pterygopodia are modified rays of the ventral fins of a male shark. Females do not have such organs. The further process of the birth of offspring in sharks proceeds according to three different scenarios, a description of which is given below.

Oviposition.

Oviparous sharks lay eggs that are similar in structure to the eggs of birds or reptiles. They have only an external difference - shark eggs do not have the usual oval or round shape - they are covered with various outgrowths, antennae or growths and their shape is often intricate.
However, these are the most ordinary eggs, from which shark fry eventually hatch. Like other oviparous animals, shark eggs contain many nutrients that allow the embryo to develop successfully.
The process of incubating eggs is quite long, sometimes more than a year. A baby shark, hatched from an egg, is capable of independent life.

The shell on shark eggs is formed during passage through the female's oviduct through the albumen and shell glands. The horny coating of shark eggs protects them from mechanical damage, dehydration and, in some cases, allows the eggs to be suspended on algae using special antennae and outgrowths.
Sometimes the sea throws shark eggs ashore, and they lie on the sand like bizarre sea creatures. In ancient times, people called such finds “mermaid purses,” without finding a correct explanation for the appearance of these strange objects.

Many species of bottom sharks reproduce by oviposition; among free-swimming ones, one can note the polar (Greenland, ice) shark, which lays up to 500 eggs, the shape and size of which resemble those of a goose. The usual clutch of most oviparous sharks does not exceed one and a half dozen eggs.
About 30% reproduce by oviposition known species sharks

Ovoviviparity.

Reproduction of sharks by ovoviviparity - unique way, characteristic only of cartilaginous fish. Why nature invented such an unusual method of reproduction, scientists still cannot explain. Perhaps this is a dead-end branch of one of many evolutionary experiments.

Ovoviviparity differs from oviparity only in that the fertilized and formed eggs do not leave the female’s body, but remain in a special section of the oviduct, called the uterus, until the fry hatch. The mother's body in this case is a kind of incubator in which the eggs can develop in relative warmth (if this term can be applied to fish) and safety.
This method of reproduction differs from true viviparity in that embryos do not receive nutrients directly from the mother through a special connecting “canal” - the placenta, but have a supply of nutrition in their egg capsule, which is enough for the entire period of intrauterine development.
Most people reproduce by ovoviviparity modern species sharks Among them are such sharks as Katran, a giant shark that gives birth to 1-2 cubs every two years, and a tiger shark that gives birth to up to 50 babies in one litter. The cubs are born well developed and able to exist independently.
You can watch a short video about how an ovoviviparous shark gives birth on this page.

Ovoviviparity of sharks is characterized by such a phenomenon as intrauterine cannibalism, when sharks that managed to hatch earlier from their eggs eat their brothers and sisters, who were late in hatching, right in the womb.

Viviparity.

During a live birth, an embryo develops in the female’s body, receiving nutrients directly from the mother’s body, by analogy with mammals.
The connection between the embryo and the female’s body does not occur immediately - for some time (sometimes up to several months), the embryo feeds on the supply of substances that are present in the yolk sac of the fertilized egg. The yolk sac then transforms into the placenta, which serves to connect the embryo with the mother's body.
It cannot be said that the most modern species of sharks reproduce in this way, since viviparity is inherent, for example, in the oldest shark - the frilled shark. A tenth of known shark species reproduce by viviparity, including all species of gray sharks, some hammerheads.

Among interesting features shark reproduction should be noted such a phenomenon as asexual reproduction or parthenogenesis. In some aquariums, there have been cases of reproduction of offspring by female sharks that were kept without males for a long time, i.e. the fact of fertilization was excluded. According to scientists, this is a kind of protective function that protects the shark species from extinction.

This is how they differ from most other fish. For this purpose, males have a special reproductive organ - a pterygopodium. Juveniles can be born from eggs or through ovoviviparity. Also, in some varieties, true viviparity occurs.

Shark reproduction and egg laying

About a third of all these sea ​​predators reproduces by eggs or capsules. They are covered on top with a dense horny shell, unlike bird shells, and may not have a round, but an intricate shape. They may have outgrowths or antennae, with the help of which they linger at the bottom among algae or stones.

The capsules contain a large number of nutrients due to which the embryo grows and develops. Incubation period can be long-lasting, sometimes lasting more than a year. After its completion, a fully formed fry is born, which is capable of obtaining food as an adult animal.

This is how most benthic species reproduce, laying no more than 15 eggs at a time. Of the free-swimming species, the polar variety is known, which lays up to 500 capsules.

Shark Reproduction: Ovoviviparity

This method differs from true viviparity in that the fertilized eggs remain to develop in the female's body. When the fry are already sufficiently formed and developed, the female gives birth to fully formed live fry. But the juveniles receive nutrients not from the mother’s body, but from the capsule in which they are located.

Ovoviviparity allows you to save offspring much more effectively than with oviparity. The deposited capsules can become easy prey for predators, but when they are in the female’s body, they are reliably protected during their development.

Cases of parthenogenesis, or asexual reproduction, have also been documented in these animals. In the absence of a male, the female is sometimes able to reproduce without fertilization.

This amazing feature allows these inhabitants of the sea to give birth to offspring in any conditions, and protects these fish from extinction.

Many species reproduce by ovoviviparity, for example, tiger and katran, which produce up to 50 fry in a litter.

Common catshark embryos

True live birth

This method is similar to the reproduction of mammals, when the embryo is located in a special organ - the uterus, and is connected to the mother’s body through the placenta. The placenta appears over time. Until this moment, the embryo develops due to its yolk sac.

Shark reproduction, in which live young are born, is considered the most progressive method. This method is found only in cartilaginous fish and is not typical for bony fish.

Australian bull shark with egg

Such reproduction of their own kind is observed not only in the most modern species, but also occurs in the most ancient ones. About one tenth of all these ocean predators living today reproduces in this way.

Viviparity as a method of reproduction for sharks is a progressive step in the evolutionary path of these species. At the same time, fully formed cubs appear, the survival rate of which is much higher than that of the larvae emerging from the eggs.

Therefore, if egg-laying fish can lay several hundred eggs, of which only a few survive to adulthood, then viviparous fish only need to give birth to several young to ensure the survival of the species.

Newborn baby California bloat shark

About sharks, the oldest sea ​​creatures, we can talk for a very long time. And we will continue this conversation on the pages of new articles:

One of oldest species animals, mysterious and little studied - these are sharks, or, as they are also called, selachians. Many myths and legends surround this representative marine fauna and form a prejudice against amazing fish. Selachians began to be systematically studied during the Second World War, during battles in the Pacific and Indian Oceans. The task was to find a means of protecting people from sea predators attacking them.

Is a shark a fish or mammal?

The list of these marine predators includes more than 400 species, polarly different: from the smallest deep-sea predator, barely growing to 17–20 cm, to the giant whale shark, a huge 20-meter multi-ton individual.

The name “mammal” speaks for itself. Those animals that feed their young with milk are called “mammals”.

The shark does not feed its young with milk; in addition, the shark breathes using such a device - “gills”. Shark is a fish.

In size, of course, these predators are comparable to dolphins or some species of whales. But in the marine kingdom there are many things that are the same in size, but different in content.

IN modern classification animal kingdoms sharks and rays constitute a subclass of Accuriformes, which belongs to the class Cartilaginous fish. Cartilaginous fish, mammals, and humans form, based on a number of similar characteristics, a single type - Vertebrates.

Skeleton bony fish consists entirely of bones, in sharks there are only cartilages. A large amount of calcium makes cartilage hard and durable. Curved, impressive size the mouth is located on the bottom of the head.

The large and soft caudal fin is asymmetrical - the upper lobe is much larger than the lower one. Bony fish move their lateral fins freely, unlike selachians.

Bony fish and sharks, what are the similarities and differences

Mammals and sharks, what are the differences?

One of unique properties- electroreception, the ability to sense electrical and magnetic signals environment. Used to detect prey, navigate in space, and maintain communication with its relatives.

Electroreceptor sensory organs are present in both selachians and rays, as well as in some species of bony fish. Among mammals, the Australian platypus and, presumably, the echidna can boast of having electroreceptors. Ampoules of Lorenzini - that's what they call it electroreceptor apparatus predator, which she successfully uses at the moment of attack.

In the process of evolution, the relief of the Earth changed - oceans arose in place of land or, conversely, continents went under the water column. Some forms of life disappeared, others appeared. Only the selachians continued to exist for almost 500 million years. Some representatives of this unique and little-studied species have remained almost unchanged.

The largest specimen is carhadon fossil, ancestor of the great white shark. Its size was restored from the found fossilized teeth, the size of which is 10–15 cm. It is assumed that seven people could fit in its mouth. The smallest living representative of the species is dwarf glow shark only 7 cm long.

The shark belongs to the phylum chordate animals, class cartilaginous fish, superorder shark (lat. Selachii). The origin of the Russian word “shark” comes from the language of the ancient Vikings, who called any fish with the word “hakall”. In the 18th century, dangerous waterfowl predators began to be called this in Rus', and initially the word sounded like “sharks”. Most of Sharks live in salt water, but some species also live in fresh water.

Shark: description and photo. What does a shark look like?

Thanks to species diversity the length of sharks varies greatly: small bottom sharks barely reach 20 cm, and whale shark grows up to 20 meters and weighs 34 tons (the weight of an average sperm whale). The skeleton of a shark has no bones and consists only of cartilage tissue. The streamlined body is covered with scales with pronounced relief protrusions, the strength of which is not inferior to teeth, and therefore shark scales are called “skin denticles”.

The shark's respiratory organ is the gill slits located in front of the pectoral fins.

Shark heart support is too weak blood pressure, therefore, to stimulate blood flow, the fish should be in motion as often as possible, helping the heart with continuous muscle contractions. Although some species of sharks feel great lying on the bottom and pumping water through their gills.

The shark lacks a swim bladder, which all bony fish have.

Therefore, the shark’s buoyancy is ensured by the giant liver, which makes up almost a third of the body weight of the predatory fish, low density of cartilage tissue and fins.

The shark's stomach is very elastic, so it can hold large amounts of food.

To digest food, the concentration of hydrochloric acid in the gastric juice is not enough, and then the sharks turn the stomach inside out, freeing it from undigested excess, and what is interesting is that the stomach does not suffer at all from numerous sharp teeth.

Sharks have excellent vision, 10 times greater than human vision.

Hearing is represented by the inner ear and senses low frequencies and infrasounds, and also provides the balance function of predatory fish.

Sharks have a rare sense of smell and can smell odors wafting through the air and water.

Predators detect the smell of blood in a ratio of 1 to a million, which is comparable to a teaspoon diluted in a swimming pool.

The speed of a shark, as a rule, does not exceed 5 - 8 km/h, although upon sensing prey, the predator can accelerate to almost 20 km/h. Warm-blooded species - White shark and mako sharks cut through the water at speeds of up to 50 km/h.

The average lifespan of a shark is no more than 30 years, but sand dogfish, whale sharks and polar sharks can live more than 100 years.

The structure of a predator's jaw depends on the lifestyle and food consumed. The shark's teeth are long, sharp, cone-shaped, with which it can easily rip the flesh of the victim.

Representatives of the gray shark family are endowed with flat and sharp teeth, which allows them to tear apart the meat of large prey.

Tiger shark teeth

The whale shark, whose main diet is plankton, has small teeth up to 5 mm long, although their number can reach several thousand.

Horned sharks, which feed mainly on bottom food, have sharp small teeth in front and a rear row of large crushing teeth. As a result of wear or loss, the teeth of predatory fish are replaced by new ones that grow with inside graze.

How many teeth does a shark have?

Comb-toothed sharks have 6 rows of teeth on the lower jaw and 4 rows on the upper jaw with total number 180-220 teeth. In the mouths of white and tiger sharks there are 280-300 teeth, which are located in 5-6 rows on each jaw. The frilled shark has 20-28 dental rows on each jaw, with a total of 300-400 teeth. The whale shark has 14 thousand teeth in its mouth.

The size of shark teeth also varies from species to species. For example, the size of the teeth of a white shark is 5 cm. The length of the teeth of sharks that feed on plankton is only 5 mm.

White shark teeth

Where do sharks live?

Sharks live in the waters of the entire world's oceans, that is, in all seas and oceans. The main distribution occurs in equatorial and near-equatorial sea waters, near coastal waters, especially in reef areas.

It is worth noting that some species of sharks, such as the common gray shark and the bullnose shark, are able to live in both saltwater and fresh water, swimming in rivers. The average habitat depth of sharks is 2000 meters, in in rare cases they descend to 3000 meters.

What does a shark eat?

The food of sharks is quite varied and depends on the specific species and habitat. Most species prefer sea ​​fish. Deep sea sharks eat crabs and other crustaceans.

White shark hunting eared seals, elephant seals And cetacean mammals, the tiger shark swallows everything. And only 3 species - largemouth, whale and giant sharks eat plankton, cephalopods and small fish.

Types of sharks, names and photographs

Modern classification of these ancient fish, which existed hundreds of millions of years ago, distinguishes 8 main orders, forming about 450 species of sharks:

Carchariformes (gray, carcharid) sharks(lat. Carcharhiniformes)

This order unites 48 genera and 260 species. The following species are considered typical representatives of the order:

• Great hammerhead shark(lat. Sphyrna mokarran )

Lives in the waters of the Atlantic, Indian, Pacific, Caribbean and Mediterranean seas. The maximum recorded length of a hammerhead shark is 6.1 m. The leading edge of their hammerhead is almost straight, which distinguishes them from other hammerhead sharks. The high dorsal fin is shaped like a sickle.

• Silk (Florida, widemouth) shark(lat. Carcharhinus falciformis)

Lives in the Mediterranean and Red Seas, found in the equatorial and adjacent latitudes of the world's oceans.

The widemouth shark is characterized by a rather dark color on the back of various shades of gray, blue, brownish-brown with a slight metallic sheen. Colors fade with age. The scales covering the skin of a shark are so small that they create the effect of their complete absence. It reaches 2.5-3.5 meters in length. The maximum recorded weight is 346 kilograms.

• Tiger (leopard) shark (lat. Galeocerdo cuvier)

Lives off the coast of Japan, New Zealand, USA, Africa, India, Australia. Tiger shark considered one of the most common shark species on Earth.

These large predators reach a length of 5.5 meters. The color of the leopard shark is gray, the belly is white or light yellow. Until the shark reaches two meters in length, transverse stripes similar to those of a tiger are noticeable on its sides. This is where its name came from. These stripes camouflage predatory fish from their larger relatives. With age, the stripes fade.

• Bull sharkor gray bull shark (lat. Carcharhinus leucas)

The most aggressive species of shark, common in tropical and subtropical oceans, you can often find this predatory fish in rivers and canals.

These huge fish have a spindle-shaped elongated body, characteristic of gray sharks, and a short, massive and blunt snout. Surface of the body blunt-nosed shark painted gray, belly white. The maximum recorded body length is 4 meters.

• Blue shark or blue shark (big shark or great blue shark)(lat.Prionace glauca )

It is one of the most common sharks on earth. The habitat of the blue shark is quite wide: it is found everywhere in the temperate and tropical waters of the World Ocean. reaches 3.8 meters in length and weighs 204 kilograms. This species has an elongated slender body with long pectoral fins. Body color is blue, belly is white.

Heterodonates (bull, horned)sharks(lat. Heterodontiformes )

The order includes one fossil and one modern gender, in which the following types can be distinguished:

• Zebra bull(Chinese bull, narrow-striped bull, narrow-striped horned) shark (lat. Heterodontus zebra)

Lives off the coast of China, Japan, Australia, Indonesia. The maximum recorded length is 122 cm. The body of the narrow-striped bull shark is light brown or white with wide brown stripes, in addition there are narrow stripes on the sides.

• Helmeted bull shark(lat. Heterodontus galeatus)

A rare species that lives off the coast of Australia. Helmet skin bull sharks covered with large and rough skin denticles. The color is light brown, with 5 dark saddle-shaped markings scattered across the main background. The maximum recorded length of the shark is 1.2 m.

• Mozambican bull(African horned) shark (lat. Heterodontus ramalheira)

The fish has a body length of just over 50 centimeters and lives off the coast of Mozambique, Yemen and Somalia. The base of the anal fin is located behind the base of the second dorsal fin. The main color of this species of shark is red-brown, with small white spots scattered throughout it. Maximum recorded length 64 cm.

Polybranchiformes (multibranched)sharks(lat. Hexanchiformes)

A primitive order representing only 6 species of sharks, with the most famous:

• frilled shark(cape bearer) (lat. Chlamydoselachus anguineus)

This shark has the ability to bend its body and attack its prey in a similar manner. The length of the frilled bat can reach 2 m, but is usually about 1.5 m in females and 1.3 m in males. The body is very elongated. The color of this type of shark is even dark brown or gray. They are distributed from the northern coast of Norway to Taiwan and California.

• Sevengill(ash sevengill shark, sevengill) (lat. Heptranchias perlo)

It is slightly more than 1 meter long and, despite aggressive behavior, is not dangerous to humans. It lives from coastal Cuban waters to the coasts of Australia and Chile.

The color of this species of shark ranges from brownish-gray to olive color, with a lighter belly. Some individuals of the ash sevengill shark have dark markings scattered across their backs, and may have light edging on their fins. Young sevengill sharks have dark spots on their sides, and the edges of the dorsal and upper lobes of the caudal fins are darker than the main color.

Lumniform sharks (lat. Lamniformes)

These are large fish, endowed with a body shaped like a torpedo. The order includes 7 genera:

• Gigantic (gigantic) sharks (lat. Cetorhinidae)

They have an average length of 15 m, but, despite their impressive dimensions, they do not pose a danger to people. The color is gray-brown with speckles. The caudal peduncle has pronounced lateral keels, and the tail of sharks is sickle-shaped. Giant sharks live mainly in Atlantic waters, Pacific Ocean, North and Mediterranean seas.

• Fox sharks (sea foxes) (lat. Alopias)

They are very long top part caudal fin equal to the length of the body. Sea foxes have a generally slender body with small dorsal and long pectoral fins. The color of sharks varies from brownish to bluish or lilac-gray, the belly is light. They grow up to 6 m in length, but are shy and try to avoid meeting people.

Distributed fox sharks in the waters North America and along the entire Pacific coast.

• Herrings(lamnovye) sharks (lat. Lamnidae)

These are the fastest sharks. A prominent representative of the family is the white shark, which has a body length of up to 6 meters. Thanks to their delicious meat, herring sharks are exterminated for commercial purposes, and are also used as objects of sport hunting in warm waters world ocean.

• False sand sharks(lat. Pseudocarcharias)

Pseudocarcharias kamoharai – the only kind kind. These fish are distinguished by their peculiar body shape, reminiscent of a cigar. The average body length is 1 m; predators are not aggressive towards humans, but when caught, they begin to bite. These sharks live in the eastern Atlantic, Indian and Pacific oceans.

• Sand sharks(lat. Odontaspididae)

Family large fish with an upturned nose and a curved mouth. Slow and not aggressive, they are considered theoretically dangerous to humans, although recorded cases of cannibalism most likely relate to gray sharks, with which sand sharks are often confused.

Sand sharks are inhabitants of all tropical and many cool seas. Maximum length The body length of this type of shark is 3.7 m.

• Largemouth (pelagic)sharks(lat. Megachasma)

Family Megachasma represented by the only one and rare species Megachasmapelagios. Representatives of the species largemouth sharks They feed on plankton and are not dangerous to humans. The body length of this species is up to 6 m in length. These sharks swim off the coasts of Japan, Taiwan and the Philippine Islands.

• Scapanorhynchus sharks (goblin sharks)) (lat. Mitsukurinidae)

They represent 1 species, which received the popular nickname “goblin shark” for a long nose beak-shaped. Length adult is about 4 m and weighs just over 200 kg. A rare deep-sea shark species lives off the coast of Japan and Australia.

Wobbegong-like(lat. Orectolobiformes)

A squad consisting of 32 species of sharks, the brightest representative which is considered to be a whale shark (lat. Rhincodon typus), growing up to 20 meters in length. A good-natured animal that allows divers to pet it and even ride on its back.

Most species feed in shallow water on mollusks and crayfish. These sharks are found in warm waters of the tropical and subtropical zones.

Sawtooth sharks(lat.Pristiophoriformes )

The squad includes single family Saw sharks or sawnose sharks (lat. Pristiophoridae), which are distinguished by a long, flat snout with saw-like teeth. The average length of an adult sawnose shark is 1.5 meters. These are common predatory fish in the warm waters of the Pacific and Indian Ocean, as well as off the coast South Africa, Australia, Japan and several Caribbean countries.

Katraniformes (spiny) sharks (lat. Squaliformes)

A numerous order, including 22 genera and 112 species. Unusual representatives of the order are the Southern dogfish, sea dog, or marigold (lat. Squalus acanthias), which can be found in all seas and oceans, including Arctic and subantarctic waters.

Flat-body sharks (sea angels, squats) (lat. Squatina)

They are distinguished by a wide, flat body, resembling in appearance. Representatives sea ​​angels have a length of slightly more than 2 meters, lead mainly night image life, and during the day they sleep, buried in the mud. They live in all warm waters of the world's oceans.

The sexual life of sharks has been studied rather poorly - after all, observing them is dangerous to health, and technically difficult.

Pioneers of sex

It was previously believed that sharks were the ones who invented sexual intercourse: researchers assumed that they were the first animals to join, ahem, genitals to exchange genetic material. All other animals, and especially plants, reproduced either with the help of external fertilization, or without it at all - by division.

However, a couple of years ago it was proven that armored fish, who appeared before the sharks, also had sex, so the palm went to them.

On the other hand, those fish became extinct long ago, but sharks still exist, so we can say that of all the organisms living on earth, they have the greatest sexual experience. During research work in Western Australia several years ago, they even found the fossilized remains of giant prehistoric fish from a genus of extinct sharks Cretaceous period, captured in a very ambiguous pose.

The ancestors of modern predators were pressed tightly against each other with their bellies and clearly did not expect that sudden death would overtake them at the most inopportune moment. By the way, some species of these fish can be called not pioneers, but retirees of sex - female Greenland polar sharks living in the waters North Atlantic, reach puberty at about 150 years of age! However, to be fair, it is worth noting that they live two or even three times longer.

Victims of violence

Can you tell on the subway in the morning which of those around you had sex last night? And those who last time Did you do this a month or two ago? How about six months? If you are not a psychic - which does not exist - then the result is predictable.

But if we're talking about about sharks, then the traces of a stormy night are immediately visible, and this is not at all a satisfied smile from the full toothed mouth - biologists can count the number of sexual intercourses a shark has by the scars on its body. The fact is that in most species of sharks there is an equal sign between sex and violence: the male literally brutally rapes the female, pouncing on her and holding her fins with his teeth. The female tries to fight back, so the gentleman also gets the worst of it.

Violence often occurs in groups: during the breeding season, males gather in schools and hunt females, who try to hide from them in shallow water. However, the male shark does not impregnate everyone; he can choose “the one” for quite a long time in order to pursue her for a long time and persistently.

It’s not just carnivorous species that behave this way: for example, giant sharks, which feed on plankton and won’t hurt flies, behave just as barbarically: scientists even believe that the huge teeth, which are not used either for hunting or for digestion, were left specifically for sexual needs.

Missionary position

Despite the fact that sharks are pioneers of sex, nature has never come up with anything better than the missionary position for them: the female and the male mate in the most classic position. Moreover, this is a prerequisite for sex, otherwise nothing will work out. When a male attacks a female, his task is to turn the lady onto her back at all costs, who fights back with all her might, using sharp teeth.

If the attempt to place the female on her shoulder blades is crowned with success, the job is done - she will fall into a state of tonic immobility, something between a trance and a coma. True, a shark needs to move in order to breathe, and in a coma it cannot do this, so more than 15 minutes of trance are fraught with death.

By the way, there are known cases when killer whales put sharks into a state of tonic immobility - not for sex, but just to have lunch.

No man? And it is not necessary

When sex turns from pleasure into torture, and you have to reproduce somehow, willy-nilly you have to look for other ways. And nature has found them for sharks: there are known cases where fertilization occurred in females without the participation of a male. True, in fact, the reason is not fear of violence, but long-term abstinence - parthenogenesis usually occurred in captivity, in aquariums, where females were kept alone for a long time.

It is believed that this defense mechanism, which protects sharks from extinction. These ancient predators also have another useful trick: they know how to store their partner’s sperm for several years and use it only at a favorable moment for themselves. Moreover, even if a shark is impregnated by several males, it will give birth to offspring from “that one” (although scientists just a few years ago put forward the theory that under such conditions, if several sharks are born, they may be from different fathers). The only thing that still remains a mystery is the mechanism for selecting the genetic material of a particular lover.

Eat your brother

Harsh fish have stern morals: many aquatic predators They eat both their own offspring and smaller relatives that accidentally turn up along the way. But sharks have gone the furthest: they are the only ones who practice fetal cannibalism. It is characteristic of ovoviviparous species that do not lay eggs in the sand, but carry them in utero.

At a certain stage, the embryo leaves the egg, and failed brothers and sisters who have not yet hatched become food for it. Is it any wonder that a shark is born a full-fledged predator, ready to tear and throw - unless he devours his own mother, of course.

To be fair, this rarely happens: nature turns on a protective mechanism, thanks to which the female after childbirth completely loses her appetite.