Jellyfish are mysterious loners. Rare and unusual species of jellyfish Aurelia coelenterata

One of the most mysterious inhabitants sea ​​depths, arousing interest and a certain fear, jellyfish can rightly be called. Who are they, where did they come from, what varieties are there in the world, what is their life cycle, are they as dangerous as popular rumor says - I want to know about all this for sure.

Jellyfish appeared more than 650 million years ago, making them one of the oldest organisms on Earth.

About 95% of the jellyfish's body is water, which is also their habitat. Most jellyfish live in salt water, although there are species that prefer fresh water. Jellyfish - phase life cycle representatives of the genus Medusozoa, "sea jelly" alternates with a nonmotile asexual phase of nonmotile polyps, from which they are formed by budding after maturation.

The name was introduced in the 18th century by Carl Linnaeus, who saw in these strange organisms a certain resemblance to the mythical Gorgon Medusa, due to the presence of tentacles that flutter like hair. With their help, the jellyfish catches small organisms that serve as food for it. The tentacles may look like long or short, pointed threads, but they are all equipped with stinging cells that stun prey and make hunting easier.

Life cycle of scyphoids: 1-11 - asexual generation (polyp); 11-14 - sexual generation (jellyfish).

Glowing jellyfish

The one who saw it glow dark night sea ​​water, this sight is unlikely to be forgotten: myriads of lights illuminate deep sea, shimmer like diamonds. The reason for this amazing phenomenon The smallest planktonic organisms, including jellyfish, serve. The phosphoric jellyfish is considered one of the most beautiful. It is not found very often, living in the benthic zone near the coasts of Japan, Brazil, and Argentina.

The diameter of the luminous jellyfish umbrella can reach 15 centimeters. Living in the dark depths, jellyfish are forced to adapt to conditions, provide themselves with food, so as not to disappear altogether as a species. An interesting fact is that the bodies of jellyfish do not have muscle fibers and cannot resist water flows.

Since the slow jellyfish, swimming at the will of the current, cannot keep up with mobile crustaceans, small fish or other planktonic inhabitants, they have to use a trick and force them to swim up to the predatory mouth opening. And the best bait in the darkness of the bottom space is light.

The body of a luminous jellyfish contains a pigment - luciferin, which is oxidized under the influence of a special enzyme - luciferase. The bright light attracts victims like moths to a candle flame.

Some types glowing jellyfish, such as Rathkeya, Equorea, Pelagia live at the surface of the water, and, gathering in large quantities, they literally make the sea burn. The amazing ability to emit light has interested scientists. Phosphors have been successfully isolated from the genome of jellyfish and introduced into the genomes of other animals. The results turned out to be quite unusual: for example, mice whose genotype was changed in this way began to grow green hairs.

Poisonous jellyfish - Sea Wasp

Today, more than three thousand jellyfish are known, and many of them are far from harmless to humans. All types of jellyfish have stinging cells “charged” with poison. They help to paralyze the victim and deal with him without any problems. Without exaggeration, for divers, swimmers, and fishermen, a jellyfish called the Sea Wasp is represented. The main habitat of such jellyfish is warm tropical waters, there are especially many of them near the coasts of Australia and Oceania.

Transparent bodies of pale blue color are invisible in the warm water of quiet sandy bays. The small size, namely, up to forty centimeters in diameter, is also not attractive special attention. Meanwhile, the poison of one individual is enough to send about fifty people to heaven. Unlike their phosphorescent counterparts, sea ​​wasps can change direction of movement, easily finding careless swimmers. The poison that enters the victim’s body causes paralysis of smooth muscles, including the respiratory tract. Being in shallow water, a person has a small chance of being saved, but even if medical care was provided in a timely manner and the person did not die from suffocation; deep ulcers form at the sites of the “bites”, causing severe pain and not healing for many days.

Dangerous little ones - Irukandji jellyfish

Tiny Irukandji jellyfish, described by Australian Jack Barnes in 1964, have a similar effect on the human body, with the only difference being that the degree of damage is not so deep. He, as a true scientist who stands up for science, experienced the effect of poison not only on himself, but also on his own son. Symptoms of poisoning - severe headache and muscle pain, convulsions, nausea, drowsiness, loss of consciousness - are not fatal in themselves, but the main risk is a sharp increase in blood pressure from a man who personally met Irukandji. If the victim has problems with cardiovascular system, then the probability of death is quite high. The size of this baby is about 4 centimeters in diameter, but its thin spindle-shaped tentacles reach 30-35 centimeters in length.

Bright beauty - Physalia jellyfish

Another very dangerous inhabitant of tropical waters for humans is Physalia - the Sea Boat. Her umbrella is painted in bright colors: blue, violet, purple and floats on the surface of the water, so it is visible from afar. Entire colonies of attractive sea “flowers” ​​attract gullible tourists, beckoning them to pick them up as quickly as possible. This is where it lurks main danger: hidden under the water are long, up to several meters, tentacles equipped with a huge number of stinging cells. The poison acts very quickly, causing severe burns, paralysis and disruption of the cardiovascular, respiratory and central nervous systems. If the meeting took place on great depth or simply far from the shore, then its outcome may be the saddest.

Giant Jellyfish Nomura - Lion's Mane

A real giant is the Nomura Bell, which is also called the Lion's Mane for some reason. external resemblance with the king of beasts. The diameter of the dome can reach two meters, and the weight of such a “baby” reaches two hundred kilos. Lives on Far East, V coastal waters Japan, off the coast of Korea and China.

Huge hairy ball getting into fishing nets, damages them, causing damage to the fishermen and striking them themselves when they try to free themselves. Even if their poison is not fatal to humans, meetings with the “Lion’s Mane” rarely take place in a friendly atmosphere.

Hairy Cyanea - the largest jellyfish in the ocean

Cyanea is considered one of the largest jellyfish. Living in cold waters, it reaches largest sizes. The most gigantic specimen was discovered and described by scientists at the end of the 19th century in North America: its dome was 230 centimeters in diameter, and the length of the tentacles turned out to be 36.5 meters. There are a lot of tentacles, they are collected in eight groups, each of which has from 60 to 150 pieces. It is characteristic that the dome of the jellyfish is divided into eight segments, representing a kind of octagonal star. Fortunately, they do not live in the Azov and Black Seas, so you don’t have to worry about them when going to the sea to relax.

Depending on the size, the color also changes: large specimens are painted bright purple or purple, smaller ones - in orange, pink or beige. Cyaneas live in surface waters, rarely descending into the depths. The poison is not dangerous to humans, causing only an unpleasant burning sensation and blisters on the skin.

Using jellyfish in cooking

The number of jellyfish living in the seas and oceans Globe truly enormous, and not a single species is in danger of extinction. Their use is limited by mining capabilities, but people have been using beneficial properties jellyfish for medicinal purposes and enjoy them taste qualities in cooking. In Japan, Korea, China, Indonesia, Malaysia and other countries, jellyfish have long been eaten, calling them “crystal meat”. Its benefits are due to the high content of protein, albumin, vitamins and amino acids, and microelements. And when properly prepared, it has a very refined taste.

Jellyfish “meat” is added to salads and desserts, sushi and rolls, soups and main courses. In a world where population growth is steadily threatening the onset of famine, especially in underdeveloped countries, protein from jellyfish can be a good help in solving this issue.

Jellyfish in medicine

The use of jellyfish for making medicines is typical, in to a greater extent, in those countries where their consumption has long ceased to be a subject of surprise. For the most part, these are countries located in the coastal areas, where jellyfish are directly harvested.

In medicine, preparations containing processed jellyfish bodies are used to treat infertility, obesity, baldness and gray hair. The poison extracted from stinging cells helps to cope with diseases of the ENT organs and normalize blood pressure.

Modern scientists are struggling to find medicine, capable of defeating cancerous tumors, without excluding the possibility that jellyfish will also help in this difficult fight.

Jellyfish are a class of multicellular invertebrates that hunt and kill their victims using tentacles.

These beautiful exotic creatures can only survive in salt water, therefore, their habitat is oceans, seas and in some cases cut off from " big water» lagoons of coral islands. Some of the species love cool water, others - warm, others live only upper layers, and the fourth - only at the bottom.

It is interesting that the representatives of the animal world in question belong to the same group as... corals. Both of these classes of creatures belong to the coelenterates.

Jellyfish are loners. They do not transmit signals to their “relatives” in any way, even if they are swept into a large pile by the current.

They were named in the mid-18th century by Carl Linnaeus, who noticed their similarity to a head. famous character ancient Greek myths - Medusa the Gorgon.

This is an amazing animal 98% consists of water, therefore, its body is almost transparent, similar to a dome, umbrella or disk made of jelly. And the “dome” moves due to muscle contraction.

Tentacles

There are tentacles along the edges of the creature. They are very different in different species: short and thick are possible, and long and thin are possible; their number ranges from four to four hundred (the number of tentacles is always a multiple of four, because these animals have an inherent radial symmetry).

Tentacles are built from containing toxic substances stinging cells and are needed for movement, hunting and holding prey. Fun fact: even a dead jellyfish can bite for about two weeks. Certain types of jellyfish are extremely dangerous for humans. For example, an animal called the Sea Wasp can poison six dozen people in a couple of minutes.

From above the animal’s body is smooth and dome-shaped, and from below it looks like an empty bag. In the middle below is the mouth opening. It can also be different: in some individuals it looks like a pipe, in others it looks like a club, in others it is wide. Undigested food remains are also removed through the mouth.

Growth and development

Jellyfish increase in size throughout their lives, and their final size depends on the species. Yes - tiny, not longer than a pair millimeters, but there are giants larger than forty meters(this is the length of the tentacles). Cyanea is the largest representative and lives in the North Atlantic.

These inhabitants of the sea no brain and sense organs, but there are light-sensitive cells that help them distinguish between darkness and light (they do not see objects). Some specimens can glow in the dark. Animals living in the depths are usually red, and those living near the surface of the water are blue.

Internal structure

The internal structure of animals is very simple. They consist of two layers:

1. The outer ectoderm, which acts as a kind of skin and muscle, contains the rudiments of nerves and germ cells.
2. Internal endoderm, which only digests food.

Jellyfish have an amazing ability to regenerate: even if you cut an animal into halves, two similar individuals will grow from them.

Classification

1. Hydroids or Hydrozoa(organisms that live only in waters that constantly contain absorbed oxygen). Relatively small (1 to 3 cm), transparent animals; four tentacles, a long mouth resembling a tube. The most famous creature of this class is Turritopsis nutricula. This the only thing known to science biologically immortal being. Having aged, it sits on the seabed and transforms into a polyp, from which new individuals then grow. Another very dangerous animal called the Cross belongs to this class. It is tiny (the largest specimens reach about 4 cm), but if it bites a person, the victim will have serious and very long-term health problems.

1. Box jellyfish (Cubozoa). This class is so named because their umbrella is not oval, but cubic. They differ from other representatives by their developed nervous system. They can swim at speeds of up to six meters per minute and adjust direction with ease. However, they are also the most dangerous for people: some individuals can even kill a careless swimmer. The most poisonous representative of cnidarians on the planet, the Sea Wasp is a representative of this class.

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Jellyfish are a very common and most amazing species of living creatures inhabiting the seas and oceans. You can admire them endlessly. What types of jellyfish are there, where they live, what they look like, read in this article.

General information about jellyfish

They belong to the coelenterates and are part of their life cycle, which has two stages: asexual and sexual. Adult jellyfish are dioecious and reproduce sexually. The role of the male is to sweep reproductive products into the water, which can immediately enter the corresponding organs of the female or be fertilized directly in the water. It depends on the type of jellyfish. The emerging larvae are called planulae.

They have the ability to exhibit phototaxis, that is, they move towards a light source. Obviously, they need to stay in the water for some time, and not immediately fall to the bottom. The freely mobile life of planulas does not last long, about a week. After this, they begin to settle to the very bottom, where they attach to the substrate. Here they are transformed into a polyp or scyphistoma, the reproduction of which occurs by budding.

This is called asexual reproduction, which can continue indefinitely until favorable conditions for the formation of jellyfish. Gradually, the body of the polyp acquires transverse constrictions, then the process of strobilation occurs and the formation of young disc jellyfish - ethers.

They are most of the plankton. Subsequently, they mature and become adult jellyfish. Thus, for asexual reproduction - budding, the water temperature may be low. But, having overcome a certain temperature barrier, dioecious jellyfish are formed.

Class of hydroid jellyfish

Coelenterates include solitary or colonial aquatic inhabitants. Almost all of them are predators. Their food is plankton, larvae and fry of fish. Coelenterate species There are ten thousand species of jellyfish. They are divided into classes: hydroid, scyphoid, and the first two classes are usually combined into a subspecies of jellyfish.

Hydroid coelenterate jellyfish are characteristic representatives of freshwater polyps. Their place habitual habitat are lakes, ponds and rivers. The body has a cylindrical shape and the sole is attached to the substrate. The opposite end is crowned with a mouth with tentacles located around it. Fertilization occurs inside the body. If a hydra is cut into many pieces or turned out the other way, it will continue to grow and live. The length of its green or brown body reaches one centimeter. Hydra does not live long, only one year.

They are free-swimming and have different sizes. The size of some species is only a few millimeters, while others are two to three meters. An example is cyanea. Its tentacles can stretch up to twenty meters in length. The polyp is poorly developed or completely absent. The intestinal cavity is divided into chambers by partitions.

Scyphoid jellyfish can live up to several months. About two hundred species live in temperate and tropical waters of the World Ocean. There are jellyfish that people eat. These are cornerota and aurelia, they are salted. Many species of scyphoid jellyfish cause burns and reddening of the body if touched. For example, chirodrofus even causes fatal burns in humans.

Jellyfish Aurelia eared

There are different types jellyfish A photo of one of them is presented to your attention. This is a scyphoid eared one. Her breathing is carried out throughout her transparent and gelatinous body, in which there are twenty-four eyes. Sensitive bodies called rhopalia are located along the entire perimeter of the body. They perceive impulses environment. It could be the light.

The jellyfish eats food and removes its remains from the body through the mouth opening, around which four oral lobes are located. They contain a burning substance that serves as a defense for the jellyfish and helps it obtain food. Aurelia is not adapted to life on land, as it consists of water.

Medusa Cornerot

It is popularly called the "Umbrella". The habitat of the jellyfish is Black, Azov and Baltic Sea. Cornerot fascinates with its beauty. The body of the jellyfish is translucent with a blue or purple edging, reminiscent of a lampshade or umbrella. Its peculiarity is that most often it swims on its side and has no mouth. Instead, small diameter holes are scattered on the blades through which it feeds. Cornerot lives and reproduces in water columns at great depths. If you accidentally come into contact with a jellyfish, you can get burned.

Unusual habitat

Scientists from Israel have proven that freshwater jellyfish are found in lakes in the Golan Heights. The children saw them for the first time. Then individual specimens were placed in a bottle and given to Professor Gofen. He carefully studied them in the laboratory. It turned out that this was a local colony of one of the freshwater hydroid jellyfish, which were described in England back in 1880. Then these jellyfish were discovered in a pool of water tropical plants. According to the professor, the jellyfish's mouth is surrounded by numerous stinging cells, with which it catches planktonic organisms. These jellyfish are not dangerous to humans.

Freshwater jellyfish

These coelenterate inhabitants inhabit the waters only of seas and oceans. But, there is one exception called the Amazon freshwater jellyfish. Its habitat is South America, namely the basin of a large river on the mainland - the Amazon. Hence the name. Today, this species has spread everywhere, quite by accident, during the transportation of fish from the seas and oceans. The jellyfish is very small, reaching only two centimeters in diameter. Now it inhabits slow, calm and stagnant waters, dams, and canals. The food is zooplankton.

The largest jellyfish

This is cyanea or lion's mane. There are different types of jellyfish in nature, but this one is special. After all, that’s what he described Conan Doyle in your story. This is a very large jellyfish, the umbrella of which reaches two meters in diameter, and the tentacles reach twenty. They look like a raspberry-red tangled ball.

In the central part the umbrella is yellowish, and its edges are dark red. The lower part of the dome is endowed with a mouth opening, around which there are sixteen large folded oral lobes. They hang down like curtains. Cyanea moves very slowly, mainly on the surface of the water. It is an active predator, feeding on planktonic organisms and small jellyfish. Habitat: cold waters. Occurs frequently, but is not dangerous. The resulting burns are not fatal, but can cause painful redness.

Jellyfish "Purple Sting"

This species is distributed in the World Ocean with warm and temperate waters: it is found in the Mediterranean and in the Atlantic and Pacific oceans. These types of jellyfish usually live far from the coast. But sometimes they can form schools in coastal waters, and can be found in large numbers on the beaches. Jellyfish are not only They are golden yellow or yellow-brown, depending on their habitat.

Jellyfish Compass

These types of jellyfish chose coastal waters as their place of residence. Mediterranean Sea and one of the oceans - the Atlantic. They live off the coast of Turkey and the United Kingdom. That's enough large jellyfish, their diameter reaches thirty centimeters. They have twenty-four tentacles, which are arranged in groups of three each. The body color is yellowish-white with a brown tint, and its shape resembles a saucer-bell, which has thirty-two lobes, which are colored brown at the edges.

The upper surface of the bell has sixteen brown V-shaped rays. The lower part of the bell is the location of the mouth opening, surrounded by four tentacles. These Their poison is potent and often leads to the formation of wounds that are very painful and take a long time to heal.

Medusa cannonball

Cannonball jellyfish lives along east coast USA to Brazil. It got its name because unusual shape perfectly smooth and round, like a cannonball. In Asian countries, these jellyfish are widely used in folk medicine. It is believed that they can cure lung disease, arthritis, and lower blood pressure.

Olindias formosa

This rare species jellyfish are found off the coast of Brazil, Argentina, and Japan. Characteristic of these jellyfish is hovering at shallow depths. When the jellyfish is in this state, its tentacles are concentrated under the cap. Due to the small number this type does not pose a danger to people, but we should not forget that they can leave very severe burns.

Portuguese man of war

This amazing creature differs from all jellyfish in that it consists of many medusoid individuals. It has a gas bubble that floats on the surface of the water, allowing it to absorb air. The tentacles of the Portuguese man-of-war can reach 50 meters when extended.

Purple striped jellyfish

This type of jellyfish can be found in Monterrey Bay. They are not yet well studied. This jellyfish has quite large sizes and can cause serious burns to humans. Stripes and rich colors appear in jellyfish as they age. Along the way warm currents The jellyfish may also migrate to the shores of Southern California. This was especially noticeable in 2012, when 130 people received burns from jellyfish (black sea nettle and purple striped one).

Mediterranean or jellyfish fried egg

This amazing creature really resembles a fried egg, or poached egg. Jellyfish live in the Mediterranean, Adriatic and Aegean Seas. Her important feature it is believed that she can move independently without relying on waves.

Darth Vader or Narcomedusa

This type of jellyfish was discovered in the Arctic. This happened quite recently. In addition to such an interesting and at the same time terrifying appearance, the jellyfish has 4 tentacles and 12 stomach pouches. While swimming, the tentacles are pulled forward to better reach their prey.

Blue jellyfish

The blue jellyfish has very stinging tentacles. It has been discovered off the coast of Scotland, in the North Sea and in the Irish Sea. The average transverse diameter of this jellyfish is 15 centimeters. Color varies from dark blue to bright blue.

Porpit porpit

It's not really a jellyfish. This creature is more commonly known as the blue button. The porpet lives on the surface of the ocean and consists of two parts: a hard golden-brown float and hydroid colonies, which in appearance are very similar to the tentacles of a jellyfish. Porpita can easily be confused with a jellyfish.

Diplulmaris Antarctica

this magnificent creature lives in deep waters Antarctica and has four bright orange tentacles as well as white tentacles. The small white dots on the jellyfish are side-spreads. They live in the jellyfish and sometimes even feed on it.

Black sea nettle

Black sea nettle - giant jellyfish with a bell 3 feet in diameter. An adult can reach 5 meters and have 24 tentacles. This type of jellyfish was discovered in the waters Pacific Ocean. they are carnivores. They prefer larvae, plankton, and other jellyfish as food.

Jellyfish is an invertebrate marine animal with a transparent gelatinous body, equipped with tentacles along the edges. She is a lower multicellular creature, belongs to the type of coelenterates. Among them there are free-swimming (jellyfish), sessile (polyps), and attached forms (hydra).

The body of coelenterates is formed by two layers of cells - ectoderm and endoderm, between them there is mesoglea (non-cellular layer), and the body also has radial symmetry. Animals of this type have the appearance of an open sac at one end. The hole serves as a mouth, which is surrounded by a corolla of tentacles. The mouth leads into the blindly closed digestive cavity (gastric cavity). Digestion of food occurs both inside this cavity and by individual cells of the endoderm - intracellularly. Undigested food remains are excreted through the mouth.

Jellyfish belong to the scyphoid class. The class of scyphoid jellyfish is found in all seas. There are species of jellyfish that have adapted to live in large rivers flowing into the sea. The body of scyphojellyfish has the shape of a rounded umbrella or bell, on the lower concave side of which an oral stalk is placed. The mouth leads into the pharynx, which opens into the stomach. Radial canals diverge from the stomach to the ends of the body, forming the gastric system.

Due to the free lifestyle of jellyfish, their structure becomes more complex. nervous system and sensory organs: clusters appear nerve cells in the form of nodules - ganglia, balance organs - statocysts, light-sensitive ocelli. Scyphojellyfish have stinging cells located on the tentacles around the mouth. Their burns are very sensitive even for humans.

Reproduction of jellyfish

Jellyfish are dioecious; male and female reproductive cells are formed in the endoderm. The fusion of germ cells in some forms occurs in the stomach, in others in water. Jellyfish combine their own and hydroid characteristics in their developmental features.

Among the jellyfish there are giants - Physaria or Portuguese man of war(from three or more meters in diameter, tentacle up to 30 m), such creatures can even eat a person. IN lately they were seen around Sea of ​​Japan, and the Japanese and Chinese, who even try to cook from them, added them to various salads, thereby poisoning quite a few people.

The jellyfish looks flabby, but it feels dense to the touch. Although it has neither an internal nor an external skeleton, it retains a certain shape. This is ensured in part by the fact that the gelatinous mass is permeated with strong connective tissue fibers. In addition, the jellyfish pumps water into itself - in the same way, an inflatable raft becomes rigid when it is inflated with air. This method of maintaining body shape, called a hydrostatic skeleton, is also characteristic of sea anemones and worms.

Jellyfish feeding

A predatory jellyfish captures food with its tentacles and digests it in the body cavity with the help of enzymes in the digestive cells.

Movement of jellyfish:

The movement of jellyfish is carried out by “stepping” and “tumbling”.

Irritability

Irritability is produced by nerve cells scattered throughout the body.

Meaning: Eaten

Some jellyfish are deadly and poisonous to humans. For example, when bitten by a cornet, significant burns can occur. When bitten by a cross, the activity of all systems of the human body is disrupted. The first encounter with a cross is not dangerous, the second is fraught with consequences due to the development of anophiloxia. A tropical jellyfish sting leads to fatal outcome, and the bite of an ordinary jellyfish goes away in 3 days and does not carry any consequences.

Interesting facts about jellyfish

Jellyfish help fight stress! In Japan, jellyfish are bred in aquariums. The smooth, leisurely movements of jellyfish calm people, although keeping jellyfish is very troublesome and expensive.

The first robotic jellyfish appeared in Japan. Unlike real jellyfish, they not only swim smoothly and beautifully, but if the owner wishes, they can “dance” to music.

A certain type of jellyfish is caught off the coast of China and eaten! Their tentacles are removed, and the “carcasses” are kept in a special marinade, which turns the jellyfish into a translucent cake of delicate thin cartilage. In the form of such cakes, jellyfish are brought to Japan, where they are carefully selected for size, color and quality. For one of the salads, the jellyfish cake is cut into thin strips about 3-4 mm wide, mixed with stewed vegetables and herbs and poured with sauce.

Jellyfish go through quite a long development path. Fertilized eggs develop into larvae that float freely in the water. These larvae then attach to the seabed and grow into polyps. As a result of division, small jellyfish can bud from the polyp. They grow to adult size and reproduce. This process is called "alternation of generations." Almost all jellyfish live in sea ​​water. However, there are also several freshwater species. In Europe, this is a freshwater jellyfish Craspedacusta with a diameter of only 2 cm, living in ponds and shallow lakes. Now it has become a rarity.

Jellyfish can be round like a ball, flat like a plate, elongated like a transparent airship, very small, like a sea wasp, and huge, like the giant of the Arctic waters, the fiery red lion's mane, whose dome-shaped body grows up to two and a half meters in height. diameter, and bundles of writhing thread-like tentacles, reaching 30 m in length, can cover a five-story building.

Much more modest in size, the pelagia jellyfish, or nocturnal jellyfish, amazes experienced sailors with its bright light in the middle of the night in the waters of the Mediterranean Sea.

Not everyone knows that the beauty of most types of jellyfish can be very deceptive. After all, to a greater or lesser extent, all jellyfish are poisonous. The only difference is that some species are practically not dangerous to humans, others sting like nettles, and a painful burning sensation can be felt for several days, and others cause paralysis that can lead to death.

There are also jellyfish that are completely harmless to humans. This is the well-known glassy-white “eared” jellyfish - Aurelia. It lives in all tropical and temperate warm seas, including here - in Cherny. These are animals summer time. Autumn storms bring death to them, so they have adapted, so to speak, to “put off” their offspring for the winter. On the eve of cold weather, small, slightly more than a centimeter, lumps of living tissue settle to the bottom of the sea, carriers genetic code aurelia. They are not afraid of storms or cold snaps, and with the arrival of spring, tiny discs separate from them, which grow into adults in one summer.

By the way, if you rub the body of Aurelia into human skin, it becomes immune to “stinging” jellyfish, such as, for example, the same Black Sea rosistoma, otherwise known as corneros.

The most dangerous of all existing jellyfish are sea wasps. They are found in warm waters Indian and Pacific oceans. It's hard to believe that this little blob of living mucus is actually a real killer. And meeting him is almost more dangerous than meeting a shark. The venom of the sea wasp is so strong that if it enters the bloodstream, it can stop a person’s heart in a few minutes. In search of food, such as bottom-living shrimp, these deadly creatures sometimes come very close to the shore. And as a result, in the coastal waters of Australia, the poison of these little killers recent years More than fifty people died.

The largest existing jellyfish is the giant arctic jellyfish, whose umbrella reaches 2.2 m in diameter; its tentacles are 35 m long. As we see, jellyfish can be gigantic! This giantess, as well as many other jellyfish, paralyze their prey with stinging cells. This poison can be very painful and even dangerous for humans. So some caution will not hurt if you come across a jellyfish with long threads in the sea. On the other hand, you don’t need to think that touching every jellyfish can cause a burn.

Speaking about jellyfish, one cannot help but recall their closest relatives - siphonophores, or, as they are also called, Portuguese man-of-war. The elongated bodies of these animals, similar to air bubbles, sway above the water and in appearance really resemble caravels under sail. Thanks to the obliquely placed comb on its float, the siphonophore goes “in full sail”, always remaining under acute angle to the wind. And behind it, like a trail, stretch very long (up to 15 meters) and very poisonous tentacles.

The main difference between the Portuguese man-of-war and a jellyfish is that it is not one creature, but a whole community of completely different individuals, each of which has its own task - some control the movement, others catch prey, others paralyze it, and others digest and divide nutrients with all members of the colony.

During the voyage, the Portuguese warship is accompanied by its own “retinue”. These are small nomei fish that hide from predators under the reliable protection of long tentacles. The poison of the stinging cells of the boats does not affect the nimble escorts.

Jellyfish can be dangerous not only for people, but also for ships. Ship engines are cooled by sea water, which enters through a special hole in the bottom. And if jellyfish get into this hole, they tightly shut off the water supply. The engine overheats and fails until divers clear the live plug.

The hairy cyanea jellyfish, caught in the northwestern part of the Atlantic in 1865, is listed in the Guinness Book of Records. Its cap was 2.28 meters in diameter, and its tentacles extended 36.5 meters. That is, if you stretch the tentacles in different sides, the length of such a jellyfish will be 75 meters. This is the longest animal on Earth!