Octopuses have become smarter thanks to the evolutionary multiplication of genes that control the development of neurons and the formation of interneuronal contacts.

Cephalopods in general and octopuses in particular are known for their high level of development, which becomes more noticeable when compared with their closest relatives: snails, toothless, etc. Suffice it to recall the outstanding abilities of cephalopods for disguise, their eyes, similar in structure to humans, and then, how they manage with eight tentacles. To coherently move so many limbs, you need to have a fairly developed nervous system.

The octopus Octopus bimaculoides was the first cephalopod to have its entire genome read. (Photo by Norbert Wu/Science Faction/Corbis.)

Large Pacific striped octopus and shrimp. (Photo by Roy Caldwell/UC Berkeley.)

Octopuses are capable of solving experimental cognitive tasks: they find and remember the way out of rather complex mazes and understand that you need to open a jar of food to get a delicious crab - which again indicates enough high level intelligence development. They can even cooperate with other predators when combined efforts are required to get prey (a year ago we wrote about how).

Obviously, the secret of octopus intelligence lies in the genes, but which ones? An article in Nature, in which Caroline Albertin ( Caroline Albertin) from the University of Chicago, Oleg Simakov from the Okinawa Institute of Science and Technology, and Daniel Rockchard ( Daniel Rokhsar) from describe the results of a complete reading of the octopus genome Octopus bimaculoides. The researchers didn't just read the genes, they also analyzed their activity in twelve different animal tissues.

It turned out that the octopus genome is unusually large: their DNA contains a total of 2.7 billion base pairs (that is, genetic “letters”), and the number of genes that encode proteins is 33,000, which is 5-6 times more than other invertebrates. Moreover, if a person’s genome is still larger in “letters” (3 billion base pairs), then in terms of coding genes, a person is inferior to octopuses - we have them, according to various estimates, from 20 to 25 thousand.

Since octopuses also have about twice as many chromosomes as other invertebrates, it was first decided that cephalopods had a doubling of the genome during evolution - a common procedure that allows copies of old genes to be assigned new functions and thereby develop new ecological niches, develop etc. But it turned out that not all genes multiplied in octopuses, but only those that belong to two specific families: protocadherins and transcription factors with a zinc finger structural motif.

Protocadherins play important role in the development of neurons and intercellular interactions between neurons: they are needed both to maintain mechanical contact and to transmit signals between cells. There are more than 150 such genes in octopuses, which is almost twice as many as in mammals. Obviously, thanks to the increased set of protocadherins, octopuses were able to multiply the number of nerve cells - they have half a billion, which is several times greater than the total number of neurons in mice. Moreover, most of the nerve cells of the octopus are collected in tentacles, where they form something like control modules.

It is believed that this became a workaround due to the lack of myelin in octopuses, a substance that envelops nerve fibers which makes the signal much more efficient. If the tentacles relied only on brain commands, the coordination of movement would take a lot of effort and time: the impulse from the limb would first travel along unmyelinated nerves to the brain for a long time, and then back. Therefore, clusters of nerve cells appeared in the tentacles, enjoying a certain autonomy; and extra protocadherins were supposed to help organize the control centers in the octopus limbs.

As for transcription factors with zinc fingers, they control the activity of other genes. Transcription factors are called proteins that regulate - enhance or weaken - the synthesis of RNA on chromosomes. Those of them, in which the spatial structure of the polypeptide chain is fastened with zinc ions, form, as you might guess, a group of factors with zinc fingers, of which a protein molecule may have more than one or two. And just zinc fingers and "grab" nucleic acids, that is, they bind to certain sequences in DNA or RNA. Such proteins are one of the most common tools for regulating genetic activity, and since the number of nerve cells and the genes responsible for them increased in octopuses, additional regulatory factors were needed for them.

In addition, other features were found in the genome of cephalopods. So, they found the ability to quickly modify proteins to change their functions - this is believed to help octopuses tune the nerve circuits to perform different tasks and ensure the plasticity of the "mind". A few hundred more special genes serve the suckers of the tentacles. Finally, six genes encoding reflectin proteins are active in the skin and help octopuses change the color and texture of their integumentary tissues, providing outstanding camouflage.

In general, we can say that the main genetic acquisitions went to the improvement of octopuses. nervous system. Is it any wonder, therefore, the hunting strategy that the large Pacific striped octopus demonstrates: sneaking up behind the shrimp, it stretches out its tentacle and lightly beats it on the head - the frightened shrimp jumps back, right into the arms of the octopus. Such a clever tactic is described in their article in PLOS ONE() Roy Caldwell ( Roy Caldwell) from the University of California at Berkeley and colleagues.

Moreover, it turned out that large Pacific striped octopuses show sufficient tolerance towards their own kind, sharing a meal with others - and, as you know, social tolerance and social communication skills in general are considered a sign of a high development of the nervous system.

Although the genes were read only in one species of octopus, it can be assumed that in this sense they are all arranged in approximately the same way, so zoologists should take a closer look at the 300 species that are known today - perhaps each of them demonstrates their inherent quick wits. But squid and cuttlefish may well have some differences in their genes: although they, along with octopuses, belong to cephalopods, their lifestyle, body structure and tentacle manipulation skills differ markedly from octopuses.

About 300 different species of octopuses live on our planet. They live in both the southern and northern hemispheres. These animals are not found only in fresh waters. Their life expectancy is not large - 1-2 years. Individuals who have lived for 4 years are rare and are considered long-livers. The inhabitants of cold waters are much larger than their brothers from warm seas and oceans. The smallest eight-legged mollusks do not exceed one centimeter in length, and the largest Haliphron atlanticus grow up to four meters.

Octopuses are aristocrats by blood

Octopuses have blood blue color. This is explained by the fact that in their blood is saturated with copper. The red blood, inherent in man and many other creatures, is made by iron, which is part of it.

Octopus heart affairs

Octopuses have a main heart and two secondary ones. The first, the largest, drives blood throughout the body of the mollusk. The other two, smaller, are responsible for pushing blood through the gills. Therefore, additional hearts are called gill hearts.

Tentacles like a tasting organ

Octopuses use their tentacles not only to grab objects, but also to determine palatability products. Each limb has ten thousand taste buds. And each suction cup can withstand a load of 100 grams.

Phenomenal ability to regenerate

In case of danger, the octopus can independently deprive itself of one or more tentacles without unnecessary regrets. But he does not suffer from this, and after a short period of time the missing limb grows back and functions no worse than the previous one. This technique is very similar to the maneuvers of a lizard throwing its tail. The octopus leaves a lone limb to be torn to pieces by enemies, and in the meantime, he runs away with all his might.

Octopuses are born actors

All octopuses easily change their color, disguising themselves as the environment. This is possible due to the presence in the body of molluscs of cells with various pigments, which stretch or narrow depending on the situation. IN normal condition The octopus is brown in color. A frightened octopus turns pale, sometimes becoming completely white. An angry one, on the contrary, blushes, frightening the offender with a bright color. The color change is useful both when hunting and when playing hide-and-seek with stronger predators.

Octopuses of the species, in addition to changing color, can successfully imitate other underwater inhabitants. Thaumoctopus mimicus easily imitate jellyfish, rays or crabs.

land octopuses

Eight-legged mollusks breathe under water with gills, but a short stay in the air does not harm them. They have a wonderful device in their body - a bag for storing water. He then helps them survive the waterless period. Some species of octopus own will leaving their familiar environment. Leaning on tentacles, they move on a solid surface in search of food in small puddles left after low tide. This technique is also effective if there is a chance of becoming a dinner for a stronger opponent. There are cases when cunning mollusks made their way into the holds of fishing boats in order to feast on a fresh catch.

Mollusk with a parrot's beak

The body of an octopus is very soft and elastic. The only hard part is beak, very similar to the beak of a parrot. With this tool, like a hammer, the octopus breaks the crab shell. Due to the flexibility of the body, the octopus can squeeze into narrow gaps in rocks and reefs. The only limit is the nose. If he climbed through, then the whole octopus will slip into the hole.

Octopuses - pedants and neat

Octopuses are very responsible for cleaning their homes. Every day, they remove debris from their burrow with a jet of water that they release from the funnel of their body. They neatly store the remains of their life activity in one place near their home, thus creating a stationary trash can for waste.

Octopuses are smart

Octopuses are considered the most intelligent among invertebrates. They recognize and become attached to their owners. After not much training, they can distinguish shapes and colors. With constant contact with a person, they become completely tame.

Octopus - keen eye

Octopuses have excellent eyesight. They see well both in the light and in the dark. The pupil of these mollusks is rectangular, like that of goats.

The blind octopus loses the ability to change color. Blinded in one eye, it changes color only from the side of the healthy eye.

floating inkwell

During the chase, the octopus throws out a cloud of ink at the enemy, which completely disorients him. And while the enemy comes to his senses, the mollusk quickly leaves the danger zone. Ink not only impairs visibility for attackers, but also knocks them off the trail due to its specific smell. In connection with these further persecution of the victim becomes impossible.

Marriage games at a distance

Octopuses are wonderful animals, often heroes sea ​​tales and myths. There are quite a few legends about mutant octopuses and killer octopuses. However, these are just speculations. Most representatives of this species are not dangerous to humans and are themselves afraid of human society. Most big octopus was caught off the coast of the United States in 1945. Its weight was 180 kilograms, and its length was 8 meters.

In ancient times, the very sight of octopuses seemed so terrible to people that they endowed mythical monsters their features. Gorgon Medusa borrowed tentacles from octopuses, which eventually transformed into snakes. And the Hydra, defeated by Hercules, had features similar to octopuses.

Octopuses or octopuses are one of the most amazing animals. For example, they have blue blood, thanks to which they can be considered among the aristocrats of the underwater world.

"I just want to eat"

Octopuses in both ancient Greek and Slavic languages ​​got their name from the words "eight" and "leg", which meant them main feature- eight tentacles. But that's not the only thing that makes octopuses amazing creatures.

For example, an octopus has three hearts and testicles are located in its head. He is an excellent camouflage, he can pretend to be a flounder, sprawled at the bottom. Able to change color. Moreover, as a person, he blushes in anger, and turns pale with fear. Due to the lack of bones, it can squeeze into the narrowest gap. And running away, it releases streams of ink - a dark liquid produced by special glands. Some species of octopuses are able to move on land, pushing off with tentacles. Their most spectacular ability is the ability to fool a predator, leaving him one of his tentacles to hide with seven others. For an octopus, this is not a problem; soon a new one will grow in place of the lost limb.

Scientists consider octopuses to be one of the most intelligent inhabitants of the sea. For example, researchers who observed the behavior of Pacific striped octopuses were amazed at how they behave with their prey. They, before inflicting a fatal blow with their beak, seem to pat the victim on the shoulder with a tentacle, as if to say: “Sorry, brother, nothing personal. I just want to eat." And the mating process of striped octopuses is accompanied by an analogue of human kisses.

For a long time there was a belief that octopuses have hypnotic abilities. Even ancient divers noticed how an octopus first stares at a crab or spiny lobster, and then it falls dead. And although modern scientists have found that some species of octopuses are able to kill victims by touching them with their tongue and at the same time poisoning them with poison secreted from salivary glands, yet the supernatural abilities attributed to these mollusks have entered the legends.

Tangaroa and the Kraken

Many peoples living by the sea deified the octopus, believing that it was he who was the ruler of the sea depths, capable of creating a whirlpool and pulling a ship with people to the bottom.

Among fantasy lovers, the most famous deity in the form of an octopus is Cthulhu, created by the fantasy of the writer Howard Lovecraft, the lord of the worlds, sleeping at the bottom Pacific Ocean, but capable of influencing the human mind. However, the literary deity had a prototype - the Polynesian god of the sea Tangaroa, whom the Polynesians represented in the form of a giant octopus.

But the most terrible incarnation of giant octopuses for Europeans, of course, was the kraken. For many centuries, sailors in taverns told terrifying stories about the attack of monsters that emerged from the abyss and drowned entire ships, entangling them with their tentacles. Homer was the first to describe the kraken in his poem. During the famous journey of Odysseus, knowing that sea ​​monster Scylla can grab only six people at a time, saves the ship at the cost of the lives of six of his comrades, who were devoured by the monster. IN ancient Greek legends Scylla is nothing more than a kraken.

True, there are two versions as to who the kraken was - a giant octopus or a squid (however, they are quite close relatives and have many similar features). And skeptics doubt that octopuses of such strength and power actually existed. It is believed that the largest octopus was caught in the United States in 1945, its weight was 180 kilograms, and its length was more than eight meters. However, it was found in the archives scientific description an octopus washed up in 1897 on St. Augustine Beach in Florida. It weighed about six tons and had tentacles 23 meters long. So it is possible that in ancient times there were still individuals large sizes, And terrible kraken was reality.

Fight with a man

There are many stories about how octopuses grabbed people in the water and tried to drag them to the depths. But most of those that have come down to us have a happy ending. An octopus will easily drown a person only if he is unconscious. On each of its eight "arms" there are about 240 suction cups, that is, there are almost two thousand of them in total, each of which has a holding force of about 100 grams. Thus, if an octopus grabs a person with all “hands”, then its maximum strength will be about 200 kilograms. But in reality, not all suckers are involved in holding prey. Therefore, a person is able to escape from the embrace of an octopus. In addition, most of the lucky ones who got out of the fight with the octopus alive had a knife with them, with which they cut off the tentacles that stuck to them.

In 1938, Charlie Edwards was testing a new diving suit he had designed with a copper helmet. When Edwards was walking along the bottom, he disturbed the octopus, and he attacked him out of fright. The octopus wrapped itself around the helmet and closed Edwards's view, but he could not peel it off. Then Charlie decided that retreat would save his life. He slowly, in weighted shoes, made his way almost blindly to the shore and came out onto land with an octopus clinging to his helmet.

And yet, probably, often the fights end in favor of the octopuses. One of the most mysterious stories about treasure hunters off the coast of Colombia. In the 20th century, a sunken Spanish schooner with silver ingots was discovered lying at a depth of 64 meters. Seven divers tried to get to the valuables lying in the hold of the ship, partially covered with sand. All of them mysteriously disappeared in the depths of the sea. locals there was no doubt that the divers were the victims of a large octopus, which chose the schooner as a home.

There were also people who said that they also tried to raise Spanish silver, but, having met at a depth with a terrible octopus, whose huge tentacles fluttered ominously in the water, and square pupils looked unkindly at the diver, preferred to get out of the water in a good way. The famous American diver Harry Riesberg decided to check these stories. He found the ship's hull covered with sand, and next to it he found the skeleton of a dead diver with a diving helmet on his head and in a torn wetsuit. This did not stop Reesberg, he made several more dives and managed to penetrate into the belly of the ship. And there he had a strange feeling that someone was watching him. Harry began to move the lantern from side to side and found that a large octopus blocked his escape route. In The Gold of Lost Ships, Reesberg wrote, "The demonic eyes of this vampire seemed to follow my every move." The fight between the diver and the octopus turned out to be just epic. Harry cut off three tentacles of the octopus with a knife, and then met with him in close combat and plunged the knife into his neck vein. But he also suffered.

Concerned about the lack of a diver, his comrade went down to the bottom and found Harry unconscious and bleeding in the arms of a dead octopus. Then he raised it to the surface, which saved Riesberg's life.

Poison handsome

The blue-ringed octopus, which lives off the western shores of the Pacific Ocean, is one of the most poisonous animals in the world. It fits in the palm of your hand and is very beautiful when phosphorescent blue rings shimmer over its body. This attracts people who take it into their hands and thereby sign their own death warrant. The venom of these octopuses is stronger than that of a snake. Their bite itself is painless, but after three minutes the effect begins to be felt - the person is dizzy and hallucinations appear, then he falls into a stupor, and death occurs in an hour. The bite of this cephalopod in 80% of cases leads to lethal outcome. Moreover, the beak of the blue-ringed octopus is so sharp that it pierces the crab shell, and therefore it is not difficult for him to pierce the clothes on a person. And the amount of tetrodotoxin poison that he injects through a bite at a time is enough to send seven people to the next world. And at the same time, these octopuses themselves pose a danger to humans even after their death.

And once, about 100 residents of the coastal village of Mahung in Vietnam ate poisonous octopuses, thinking they were eating squid. The consequences of this meal were terrible. Two eaters died, 85 landed in the hospital, the rest were limited to gastric lavage.

Octopuses are perhaps the most amazing among the molluscs that live in the depths of the sea. Their strange appearance surprises, delights, sometimes frightens, the imagination draws giant octopuses that can easily drown even big ships, this kind of demonization of the octopus was greatly facilitated by the work of many famous writers, for example, Victor Hugo in his novel "Toilers of the Sea" described the octopus as "the absolute embodiment of evil." In reality, octopuses, of which there are more than 200 species in nature, are completely harmless creatures, and it is more likely that they should be afraid of us, people, and not vice versa.

The closest relatives of octopuses are squid and cuttlefish, they themselves belong to the genus cephalopods, a family of octopuses proper.

Octopus: description, structure, characteristics. What does an octopus look like?

The appearance of an octopus is confusing, it is not immediately clear where its head is, where its mouth is, where its eyes and limbs are. But then everything becomes clear - the sac-shaped body of an octopus is called a mantle, which is fused with a large head, on its upper surface there are eyes. The eyes of an octopus are convex.

The mouth of an octopus is tiny and surrounded by chitinous jaws called a beak. The latter is necessary for the octopus to grind food, since they do not know how to swallow prey whole. He also has a special grater in his throat, she grinds pieces of food into gruel. Around the mouth are tentacles that are genuine calling card octopus. The tentacles of the octopus are long, muscular, their lower surface is dotted with suckers of different sizes that are responsible for taste (yes, the taste buds are on the octopus suckers). How many tentacles does an octopus have? There are always eight of them, in fact, the name of this animal came from this number, since the word "octopus" means "eight legs" (well, that is, tentacles).

Also, twenty species of octopuses have special fins that serve as a kind of rudders when they move.

An interesting fact: octopuses are the most intelligent among mollusks, the octopus brain is surrounded by special cartilage, strikingly similar to the skull of vertebrates.

All the senses of octopuses are well developed, especially vision, the eyes of octopuses are very similar in structure to human eyes. Each of the eyes can see separately, but if the octopus needs to examine some object more closely, the eyes easily approach and focus on a given object, in other words, octopuses have the rudiments of binocular vision. And octopuses are able to pick up infrasound.

Structure internal organs octopus is extraordinarily complex. For example, their circulatory system is closed, and the arterial vessels are almost connected to the venous ones. The octopus also has three hearts! One of them is the main one, and two small gills, whose task is to push blood to the main heart, otherwise it already directs the flow of blood throughout the body. Speaking of octopus blood, it's blue! Yes, all octopuses are real aristocrats! But seriously, the color of the blood of octopuses is due to the presence of a special pigment in it - geocyamine, which plays the same role in them that we have hemoglobin.

Another interesting body that the octopus possesses is the siphon. The siphon leads to the mantle cavity, where the octopus draws water, and then, sharply releasing it, creates a real jet that pushes its body forward. True, the octopus’s jet device is not as perfect as that of its squid relative (which became the prototype for creating a rocket), but it’s also up to par.

The sizes of octopuses differ from species, the largest of them has 3 meters in length and weighs about 50 kg. Most species of medium octopuses are from 0.2 to 1 meter in length.

As for the color of octopuses, they usually have red, brown, or yellow colors, but they can also easily change their color like that. Their color change mechanism is the same as that of reptiles - special chromatophore cells located on the skin can stretch and contract in a matter of seconds, simultaneously changing color and making the octopus invisible to potential predators, or expressing its emotions (for example, angry the octopus turns red, even turns black).

Where does the octopus live

The habitat of octopuses is almost all the seas and oceans, with the exception of northern waters, although they sometimes penetrate there. But most often octopuses live in warm seas, both in shallow water and at very great depths - some deep-sea octopuses can penetrate to depths of up to 5000 m. Many octopuses like to settle in coral reefs.

What do octopuses eat

Octopuses, however, like other cephalopods, are predatory creatures; their diet consists of a variety of small fish, as well as crabs and lobsters. They first capture their prey with tentacles and kill with poison, then they begin to absorb, since they cannot swallow whole pieces, then they first grind the food with their beak.

Octopus lifestyle

Octopuses are usually sedentary, sedentary, most of the time they hide among reefs and sea rocks, leaving their hiding place only to hunt. Octopuses live, as a rule, one by one and are very attached to their site.

How long do octopuses live

The life span of an octopus is on average 2-4 years.

Octopus Enemies

One of the most dangerous enemies of the octopus in Lately is a person, which contributes to a large extent to cooking, because many delicious and delicious dishes can be prepared from an octopus. But besides this, the octopus also has other natural enemies, various marine predators: sharks, sea lions, seals, killer whales are also not averse to eating octopus.

Is an octopus dangerous for humans?

It is only on the pages of books or in various science fiction films that octopuses are incredibly dangerous creatures, capable of not only easily killing people, but also destroying entire ships. In reality, they are quite harmless, even cowardly, at the slightest sign of danger, the octopus prefers to flee, no matter what happens. Although they usually swim slowly, in case of danger they turn on their jet engine, allowing the octopus to accelerate to a speed of 15 km per hour. They also actively use their ability of mimicry, merging with the surrounding space.

Some danger to scuba divers can only be represented by the most large species octopuses and then only during the breeding season. At the same time, of course, the octopus itself will never be the first to attack a person, but defending itself, it can sting him with its poison, which, although not fatal, will, of course, cause some unpleasant feelings (swelling, dizziness). The exception is the blue-ringed octopus, which lives off the coast of Australia, whose nerve poison is still fatal to humans, but since this octopus leads a secretive lifestyle, accidents with it are very rare.

Types of octopuses, photos and names

Of course, we will not describe all 200 species of octopuses, we will focus only on the most interesting of them.

As you probably guessed from the name, this is the largest octopus in the world. It can reach up to 3 meters in length and up to 50 kg of weight, but these are the largest individuals of this species, on average, a giant octopus has 30 kg, and 2-2.5 meters in length. It lives in the Pacific Ocean from Kamchatka and Japan to the western coast of the USA.

The most common and well-studied species of octopus that lives in the Mediterranean Sea and Atlantic Ocean, from England to the coast of Senegal. It is relatively small, its body length is 25 cm, and together with the tentacles 90 cm. The body weight is on average 10 cm. It is very popular in the cuisine of the Mediterranean peoples.

And this one beautiful view The octopus, which lives off the coast of Australia, is also the most dangerous among them, since it is its poison that can cause cardiac arrest in humans. One more characteristic feature of this octopus is the presence of characteristic blue and black rings on its yellow skin. A person can be attacked only in defense, so in order to avoid trouble, you just need to stay away from him. And it is also the most little octopus, the length of his body is 4-5 cm, tentacles - 10 cm, weight 100 grams.

Octopus breeding

And now let's look at how octopuses breed, this process is very interesting and unusual for them. Firstly, they reproduce only once in their lives, and this action has dramatic consequences for them. Before mating season one of the tentacles of the male octopus turns into a kind of sexual organ - hectocotylus. With its help, the male transfers his spermatozoa to the mantle cavity of the female octopus. After this act, the males, alas, die. Females with male sex cells continue to lead for several months ordinary life and then they lay eggs. There are a huge number of them in the masonry, up to 200 thousand pieces.

Then it lasts for several months until the young octopuses hatch, during this time the female becomes an exemplary mother, literally blowing dust particles from her future offspring. In the end, the female, exhausted from hunger, also dies. Young octopuses hatch from eggs completely ready for independent life.

• More recently, many people heard the famous octopus Paul, the octopus oracle, the octopus predictor, predicting results with amazing accuracy. football matches at the European Championships in Germany in 2008. In the aquarium where this octopus lived, two feeders with the flags of the opposing teams were placed, and then the team from whose feeder the octopus Paul began his meal won the football match.
• Octopuses play a significant place in the erotic fantasies of people, and for quite a long time, so back in 1814, a certain Japanese artist Katsushika Hokusai published an erotic engraving "The Dream of the Fisherman's Wife", which depicts a naked woman in the company of two octopuses.
• It is quite possible that as a result of evolution after millions of years, octopuses will develop into sentient beings like people.

Octopus life video

And finally, interesting documentary about octopuses from National Geographic.

Octopuses are the most famous representatives of cephalopods, having eight long tentacles - “arms” (sometimes they are called legs). "Hands" are interconnected by a thin membrane and have from one to three rows of suction cups.

There are about 2000 suckers on all eight tentacles of an adult octopus, each of which has a holding force of about 100 g, and, unlike those created by man, the octopus suckers require effort when holding, and not when sucking, that is, they are held only by muscle effort.

More than 300 species of octopuses live in all tropical and subtropical seas and oceans, from shallow water to depths of 100-150m.

Octopuses have three hearts: one (main) drives blood throughout the body, and the other two - gills - push blood through the gills.

Did you know that octopuses have blue blood?

The heart stops beating when the octopus starts to swim. That is why octopuses most often move as if crawling, and do not swim quickly.

Thanks to their soft and elastic body, octopuses can penetrate holes and crevices that are much smaller than their usual body sizes, which allows them to hide in all sorts of shelters intricately.

Many zoopsychologists consider octopuses to be the smartest among all invertebrates in many respects: they can be trained, trained, have a good memory, and distinguish geometric shapes.

The common octopus has the ability to change color, adapting to environment. If the octopus is scared, it turns white, if angry, it turns red.

When the octopus is frightened, it releases trickles of ink - a dark liquid produced by special glands. This liquid hangs in the water in the form of shapeless translucent spots. There are speculations that these spots are meant to distract an attacker and buy the octopus time to escape.

octopuses have protective device- autotomy: a tentacle caught by the enemy can come off due to strong muscle contraction, later this tentacle will grow back.

Some species of octopus are poisonous. For example, blue-ringed octopuses that live off the western shores of the Pacific Ocean are among the most poisonous animals in the world.

The female can lay up to 400 thousand eggs. She takes care of them herself, ventilates them, passing water through the so-called siphon. Tentacles she removes foreign objects and dirt. During the entire period of egg development, the female remains at the nest without food and often dies after the appearance of offspring.

The brain of an octopus is donut-shaped and is located around the esophagus.

Octopuses are able to perceive sound, including infrasound. On each "hand" there are up to ten thousand taste buds that determine the edibility or inedibility of an object.

The sizes of octopuses range from 1 centimeter (males Argonauto argo) up to 4 meters (Haliphron atlanticus).

Before the invention of scuba gear to observe life marine life in natural conditions, knowledge about their lifestyle and behavior was rather limited. In that era, octopuses were perceived as ferocious, cunning and extremely dangerous animals. The reason for this was probably their appearance: snake-like tentacles, gaze big eyes, suckers serving (as it was mistakenly believed) for sucking blood from the victims.

And this is a blue-ringed octopus (Blue ringed octopus - Hapalochlaena lunulata) - it looks very small (3-5 cm), but according to scientists, it is one of the five most poisonous sea ​​creatures. Its poison is deadly to humans, not to mention the small crabs and shrimp on which it hunts. Such virtues of the octopus were popularized for the public, being beaten by directors in spy films, for example about James Bond. He bit someone on the nose.

Responsibility for the death of people at sea under unclear circumstances was often assigned to octopuses. The human imagination spawned tales of giant octopuses(octopuses), capable of not only killing a person, but also sinking a large sailing ship.

The dream of all photographers is the imitation octopus (Mimic Octopus or Thaumoctopus mimicus), it was first scientifically described and identified as a separate species in the late nineties just off the coast of Sulawesi. Unlike other octopuses, which increasingly imitate something stationary, this species imitates the behavior of other animals. First of all, adjusting to the shape and manner of movement, he can imitate a stingray, a flounder fish, a sea snake and even a jellyfish. He actively uses his skills in hunting and defense. Its dimensions are small - 30-50 cm.

The word "octopus" has become a metaphor for criminal organizations with extensive networks, often integrated into state bodies.

Another funny species of octopus is the short-eared or coconut octopus (Coconut Octopus or Amphioctopus marginatus), being small in size (8-10 cm), it found an ideal home for itself in the form of one or two halves of a coconut (sometimes it uses paired shell shells). It can be found sitting at the bottom and covering itself with half a coconut, or it will sit in one half and close the other half like a lid. This behavior is typical primarily for Indonesia, when there are no coconuts at the bottom, then it can burrow into the sand or hide in a mink.

A huge contribution to the "rehabilitation" of octopuses was made by Jacques Yves Cousteau.