It has 9 tentacles and releases ink. Jellyfish, corals, polyps. Octopuses have a very short lifespan.
Can an octopus really produce ink?
The ability of cephalopods to "splurge" has long been known. In a moment of extreme danger, they throw out a jet of black liquid from the funnel. The ink spreads in the water in a thick cloud, and under the cover of a "smoke screen" the mollusk more or less safely escapes from the chase. Dive into some crevice or run away, leaving the enemy to wander in the dark.The ink contains an organic dye from the melanin group, similar in composition to the pigment that dyes our hair. The shade of ink is not the same for all cephalopods: for cuttlefish it is blue-black (in a strong dilution of the “sepia” color), for octopuses it is black, for squids it is brown.
The ink is produced by a special organ - the pear-shaped outgrowth of the rectum. It's called an ink bag. This is a dense bubble, divided by a partition into two parts. The upper half is reserved for a spare tank, it stores ink, the lower half is filled with the tissues of the gland itself. Her cells are stuffed with grains of black paint. Old cells are gradually destroyed, their paint dissolves in the juices of the gland - ink is obtained. They enter the "warehouse" - they are pumped into the upper vial, where they are stored until the first alarm.
Not all contents of the ink sac are ejected at once. common octopus can put a "smoke screen" six times in a row, and after half an hour it completely restores the entire spent ink supply. The coloring power of the ink liquid is unusually great. In five seconds, a cuttlefish paints all the water in a tank with a capacity of five and a half thousand liters with ejected ink.
BUT giant squid spewing from the funnel so much inky liquid that sea waves become cloudy in a space of a hundred meters!
Cephalopods are born with a sac filled with ink. One almost microscopic baby cuttlefish, barely getting out of the egg shell, immediately colored the water with five ink volleys.
And what an unexpected discovery was made by biologists in last decade. It turned out that the traditional idea of a "smoke screen" cephalopods should be thoroughly reviewed. Observations have shown that the ink thrown out by cephalopods does not dissolve immediately, not before they stumble upon something. For a long time, up to ten minutes or more, they hang in the water as a dark and compact drop. But the most striking thing is that the shape of the drop resembles the outlines of the animal that threw it out. The predator, instead of the fleeing victim, grabs this drop. That's when it "explodes" and envelops the enemy in a dark cloud. The shark is completely confused when a flock of squid simultaneously, like from a multi-barreled mortar, throws out a whole series of "ink bombs". She rushes back and forth, grabs one imaginary squid after another, and soon everything is hidden in a thick cloud of ink scattered by her.
The zoologist put the squid in a tub and tried to catch it with his hand. When his fingers were inches from the target, the squid suddenly darkened and seemed to Hal to freeze in place. In the next moment, Hal grabbed... an ink mock-up that fell apart in his hands. The deceiver swam at the other end of the tub. Hal tried again, but now he kept a close eye on the squid. When his hand approached again, the squid darkened again, threw out the "bomb" and immediately became deathly pale, then darted invisible to the far end of the tub.
What a subtle maneuver! Squid did not just leave his image instead of himself. No, it's a dressing up scene. At first, it attracts the attention of the enemy with a sharp change in color. Then he immediately replaces himself with another dark spot - the predator automatically fixes his gaze on it - and disappears from the scene, having changed his outfit. Please note: now his color is not black, but white.
Cunning on inventions of nature.
The ability of cephalopods - cuttlefish, octopuses, squids - to "splurge" has long been known. In a moment of danger, these animals throw out a jet of black liquid. The "ink" spreads in the water in a thick cloud, and under the cover of the "smoke screen" the mollusks try to get away from the chase.
"Ink" in cephalopods produces a special organ - a pear-shaped outgrowth of the rectum - it is called the ink sac. This is a dense bubble, divided by a partition into two parts. In the lower half there is a special gland, which produces black paint. After that, it enters the "warehouse" - it is pumped into upper part where it is stored until the first alarm.
The shade of “ink” is not the same for all cephalopods: in cuttlefish it is blue-black, in octopuses it is black, in squid it is brown. Cuttlefish have been known to people since time immemorial, and we can say that these animals have left a mark on human culture, because for many centuries people wrote them with “ink”.
Not all contents of the ink bag are ejected at one time. An ordinary octopus can put a "smoke screen" six times in a row, and after half an hour it completely restores the entire stock of "ink" used up.
The coloring power of the ink liquid is unusually great. In 5 seconds, a cuttlefish paints all the water in a tank with a capacity of 5.5 thousand liters with ejected "ink". And giant squids spew so much inky liquid that the sea waves become cloudy in a space of a hundred meters.
Recently, biologists have made an unexpected discovery. Observations have shown that the liquid ejected by cephalopods does not dissolve immediately, but for a long time - up to ten minutes or more - hangs in the water as a dark and compact drop. The most striking thing is that the shape of this drop resembles the outlines of the animal that threw it out. The predator, instead of the fleeing victim, grabs its disembodied double. That's when it explodes and envelops the enemy in a dark cloud.
It is interesting to watch how an aggressive shark becomes completely confused when a flock of squid simultaneously, like from a multi-barreled mortar, throws out a whole series of "ink bombs". The predator rushes about in all directions, grabs one imaginary squid after another, and soon the whole thing disappears in a thick cloud of scattered ink.
Some cuttlefish, living in the eternal darkness of the depths, in contrast, spewing a bright, luminous cloud that leads enemies into the same confusion.
Moray eels cause a lot of trouble to octopuses. When the predator, breaking through the "smoke screen", tries to grab the fugitive, he falls like a stone to the bottom. But strangely, the moray eel pokes at the petrified octopus several times and then ... swims away. What happened to the bloodthirsty moray eel, why didn't she grab the victim? It turns out that the "ink" of octopuses has the properties of a drug and paralyzes the olfactory nerves of moray eels! Having been in an ink cloud, she loses the ability to recognize the smell of a lurking fugitive. The paralyzing effect of the octopus drug lasts for more than an hour!
How does a cuttlefish move?
It will be strange for you to hear that there are many living beings for whom "lifting oneself by the hair" is in the usual way their movement in the water. The cuttlefish moves in the water in this way: it takes water into the gill cavity through the lateral slit and a special funnel in front of the body, and then vigorously throws out a stream of water through the said funnel; at the same time, according to the law of counteraction, it receives a reverse push, sufficient to swim quite quickly with the back side of the body. The cuttlefish can, however, direct the tube of the funnel sideways or backwards and, rapidly squeezing water out of it, move in any direction.
The movement of the jellyfish is also based on the same: by contracting the muscles, it pushes water out from under its bell-shaped body, receiving a push in reverse direction. Dragonfly larvae and other aquatic animals use a similar example when moving.
Domain: eukaryotes
Kingdom: Animals
Type: shellfish
Class: cephalopods
A majestic inhabitant of the sea, small and large, the octopus is still a mystery to people. A spherical body, long tentacle arms, a nose-beak and the highest intelligence combined in one animal and turned it into a hero of Hollywood thrillers. However, meaningful behavior and a formidable appearance is not yet a reason to classify an octopus as a monster.
Description of the octopus
Everything about the structure of an octopus is unusual, and the answer to the question of how many hearts an octopus has will surprise many: it has three. On Earth, few animals have such an unusual supply of hearts. Earthworm and mexin fish even outdid the clam and acquired five and four hearts.
The order of octopuses includes all species, from the smallest to giants, living in all subtropical and tropical seas and oceans of the planet.
Structure
What a simple layman takes for a head is actually the body of a mollusk. It is soft, oval in shape, and rather short in relation to its tentacles. Where the “hands” of the octopus converge is the mouth, which is armed with two beak-shaped jaws. The pharynx of the animal resembles a grater, with the help of which it grinds food. Powerful jaws and a strong grater with rows of small teeth split the shell of mollusks and allow you to get to the most tender meat.
Arms-tentacles, in the amount of 8 pieces, help the mollusk move and grab food. Between themselves they are connected by membranes. On their inner surface there are suction cups responsible for holding prey. One individual can count up to 2,000 such suckers. On the tentacles are located and taste buds animal, telling him whether edible prey fell into "hands".
Interesting! An octopus has 6 arms and 2 legs. Two tentacles are adapted to walk along the bottom, which he successfully does at great depths.
The eyes of the cephalopod mollusk are equipped with a lens, and are very similar to human ones, only the pupil is rectangular, and not round, like in humans. That is why his gaze seems to us to be alien reasonable and wise.
The octopus does not have an organ of hearing, and it breathes with gills. As for hearts, he really has three. The main one is responsible for driving blue blood throughout the body of the mollusk, the other two are located under the gills, and push the blood through them.
Color
AT calm state the animal is painted Brown color. However, the skin cells contain pigments that help the mollusk quickly change color. If the octopus is frightened of something, it turns white, and when it is very angry, its body becomes crimson. During the hunt, the octopus, like a chameleon, can reproduce on its skin the pattern of the surface behind which it hid.
The size
The standard length for males is 1.3 meters, for females - 1.2 meters. It is measured taking into account the tentacles, while the body of a mollusk can be from 30 to 50 cm long. The weight reaches 10 kg, but most specimens weigh from 5 to 7 kg. As you can see, there is no impressiveness here. Legends about giant octopuses were written in antiquity, when people did not have the opportunity to take a closer look at this harmless creature.
Interesting! Most big octopus is a rock octopus. In the Guinness Book, a mollusk with a tentacle length of 3.5 meters and a weight of 58 kg is officially registered.
Habitat
Permanently living in tropical and subtropical waters, the octopus prefers water salinity of at least 30%. Some species live in shallow water, others like to get deeper, 100-150 meters from the surface.
For a quiet life, he needs rocky shores, where he can make himself a refuge in one of the natural caves. Without a skeleton, the mollusk easily climbs into any hollow niches and crevices, hiding from predators and resting in them during the day. He goes hunting at night. If there are no rocks, the octopus does an excellent job of building a real fortress from improvised materials or digs a deep hole in the ground, equipping its nest.
Behavior
The mollusk loves its home and keeps it in perfect cleanliness, sweeping out all the garbage with a jet of water from the funnel. He stores leftovers outside the shelter.
Arranging a house, the octopus makes it wide inside, leaving a narrow passage to protect itself from enemies.
The octopus loves to drag into the house everything that is badly lying on seabed. boxes, plastic bottles, rubber boots, tires can become his home, but he will definitely drag something there.
For wintering, the mollusk goes to the depths of the ocean, and in summer it prefers to hunt in shallow water.
Nutrition
The main diet of the animal consists of crayfish, crabs and other shellfish. However, he can eat anything that moves, if he manages to cope with it. Its menu includes fish, plankton, and snails. To get food, the octopus learned to disguise itself well. Seeing a potential victim, he merges with the situation. When the prey has approached the distance of the throw, the octopus pounces on it and releases poison, paralyzing the game. Poison is produced in salivary glands ah of the animal and enters the victim through the wound made by the beak.
Enemies
Whales, killer whales, dolphins, moray eels, seals, sea lions, sharks and large sea birds- all this natural enemies octopuses. Man also hunts him. Who among us has not tried a cocktail of seafood with small octopuses or has not been treated to canned octopus meat.
reproduction
For reproduction in males, one tentacle was modified into a copulatory organ. The mating dance of animals resembles friendly tentacle shaking. The male holds the female for them, fertilizing her. A week passes, and the female octopus goes to lay eggs. For masonry, she selects a well-hidden place, and the masonry itself looks like a large bunch of grapes.
Mother octopuses are very caring and fearless. They desperately protect their offspring, care for them, providing future octopuses with an influx of fresh water and constantly cleaning the eggs of dirt and debris. The rate of development of offspring depends on the temperature of the water. The usual incubation period is 4 to 6 weeks.
Interesting! The life span of octopuses is 4 years, but females live less, averaging about two years. Puberty in females, it occurs at a weight of 1 kg, and males are ready for mating even at a weight of 100 g.
On the days when the octopus chooses a bride for himself, he becomes aggressive and forgets to be careful. A meeting with a large individual at such a moment can result in serious injuries for a person.
Of course, a large octopus inspires respect and a share of fear, but the myths dispelled by science about the bloodthirstiness of the animal led him to the page of children's books and cartoons. In them he is funny and funny.
Adults entrusted octopus Paul with predicting the outcome of matches at the 2010 World Cup. And he did not let them down, 80% of his predictions turned out to be correct. Unfortunately, the age of the octopus is short-lived, and we will have to look for another oracle.
The common octopus, also called the octopus, is typical, besides major representative families.
The body weight of large individuals reaches 50 kilograms, while the length of each tentacle is on average 2 meters, that is, the span of the tentacles reaches 4 meters.
The body length of the largest individuals living on Far East and in Primorye, it can be 4 meters, their span of tentacles can reach up to 5 meters, and they weigh 70-80 kilograms.
Each octopus lives on a certain area of the bottom. During a storm, octopuses sink to the depths, after which they return to their territory again. Often they live in shelters - crevices between underwater rocks, in grottoes and under stones. Some individuals dig holes on their own.
And others build real impregnable fortresses, pulling shells, stones and crab shells into a pile. In the upper part they make a crater in which they are located. Quite often, these mollusks close their dwellings with a flat stone. Sometimes octopuses settle in dishes that fall to the bottom. When an octopus gets out of its hiding place, it does not drop the lid, but holds it in front of it like a shield. If he is in danger, he closes himself with his shield. When retreating, the octopus backs into the dwelling, hiding behind a stone.
Octopuses build their shelters, as a rule, at night. Until midnight, they remain in the shelter, and then get out in search of stones. Octopuses can drag huge rocks that are 5-10 times their own body weight.
Octopus - shellfish terrifying on the marine life. These mollusks try to avoid meeting with their relatives. As a rule, if a larger individual appears, a small octopus immediately swims away, even if he is the owner of the site. But if two equal opponents meet, completely different events develop.
When an invader invades the territory of an octopus, the owner immediately crawls out of the shelter, climbs to the top of the stone, turns purple and releases two tentacles towards the intruder. The alien performs the same response actions, as a result, individuals are intertwined with tentacles and freeze. They act like two fighters shaking hands before a fight.
When they tense up, their tentacles stretch out and the octopuses begin to pull each other. After such an effort, the defeated opponent disentangles himself from the tentacles and crawls away. And the winner, as if on a pedestal, perches on a stone.
Why do octopuses change color
Its color depends on the mood of the octopus, it changes instantly depending on the situation. When the octopus is calm, its body has a gray-brown color, and when excited, the color becomes from golden and pink to bright red. To scare away enemies, the octopus sits on a stone and starts flashing different colors, while the change occurs instantly, then the color becomes monotonous red, then the body is covered with a mosaic of spots.
The ability to change color is associated with the presence in the body of the octopus of pigment cells called chromatophores. These cells are found in the top layer of the skin. They contain paint in three shades: red-brown, black and yellow. Each cell produces a pigment of only one color.
Age spots are very elastic, they can increase dozens of times due to small muscles. When the area of the chromatophore changes, the color is weakened or intensified. Cells contract or stretch instantly. Thanks to this, different tones of the overall color are created.
Octopus food
Octopuses are predators of the lurking type. These predators hide in shelters and wait for lobsters, fish, crabs or lobsters passing by. When the prey approaches, the octopus swiftly rushes at it and envelops it with its tenacious tentacles. Octopuses prefer king crabs. Having caught a crab, the predator carries it to its shelter. Octopuses also prey on flounders and gobies.
Suction cups on the tentacles help the octopus to hold prey. These suckers are very reliable - one sucker with a diameter of about 3 centimeters can withstand a victim weighing about 2-3.5 kilograms.
And given that there are hundreds of suction cups on the tentacles, it becomes clear that it is impossible to escape from such a deadly grip. Scientists have done a lot interesting experiences, which helped determine the strength of the suction cups. living in an aquarium, they threw a crab that was tied to a dynamometer.
The predator instantly grabbed the victim and tried to hide in the lair, but the crab was tied, then the octopus stuck to the crab and began to pull it with force. The octopus held the crab with 3 tentacles, and used the rest as a support, sticking to the bottom of the aquarium. Individuals weighing 1 kilogram or more had a strength of about 18 kilograms.
These marine animals recognize tastes not with their tongue, but with their tentacles. Their tongues are converted into graters. Tasting food is carried out using the inner surface of the tentacles and suckers. Octopuses have a very delicate sense of taste, they taste even their enemies. If you drop a small drop of water from the aquarium in which (the sworn enemy of the octopus) lives next to the mollusk, then it will turn purple and immediately rush to run.
Octopus behavior
AT daytime octopuses, as a rule, lie down, and their bodies are blurred shapelessly. In order to wake up an octopus, scuba divers prick it with a sharp twig or tickle it. The clam shudders, rises and unwinds its tentacles. The color immediately becomes purple or bright red. When the swimmers move away from the octopus for some distance, he again takes up his previous position, and his body turns pale. If you continue to provoke the octopus, he will throw out his tentacles and try to grab the offender with them. But the tentacles move slowly, so they can be easily dodged. If the octopus, nevertheless, grabbed a person, it is rather difficult to get rid of his “embrace”, since these mollusks have great strength. But the octopus understands that the person does not suit him for food and releases him himself.
Small individuals act in a completely different way, when they notice a person, they immediately attach themselves to a stone and turn pale, disguising themselves as it. If you touch the mollusk, it immediately breaks off, acquires a streamlined shape, throws water out of the body and quickly begins to rise to the surface of the water. At such a moment, octopuses almost always release an ink cloud.
Octopuses always swim towards the shore, where they often get into the surf. This reaction of the mollusks is due to the fact that their main enemies are killer whales and sharks, which are afraid to approach the coastline.
The ink cloud is effective method protection from opponents, as it serves to disorientate them. The ink released from the funnel hangs in the water column in a small black cloud, sometimes there may be a reddish tint. The cloud distracts the offender, and the octopus manages to escape. Mollusks can release a cloud about 5-6 times, but each time its size decreases. When the octopus is at the bottom, it releases ink extremely rarely, this only happens when there is not a single escape route left. The ink hangs over the mollusk and creates a veil, hiding the owner.
The ink fluid in octopuses is formed in the ink sac, which is a pear-shaped outgrowth of the rectum. The ink bag consists of two reservoirs separated by a partition. One reservoir stores ink, the other produces an ink gland. It is divided by numerous cells into chambers filled with grains of black pigment.
In their shelters, octopuses feel calm, when they are disturbed, they open their tentacles like a fan and close the entrance with them. It is extremely difficult to force an octopus to get out of the shelter. This only works if the shelter has 2 entrances.
When the clams return home, they behave very interestingly. First, they launch a couple of tentacles into the lair, check if there is anyone there, after that they begin to clean their house, throwing algae, garbage and stones out of it.
During the attack, the octopus opens its tentacles in the form of an umbrella, between which there is a strong black beak. The bites of these mollusks can be poisonous. The poison is located in the posterior pair of salivary glands. With the help of poison, the octopus paralyzes crabs and fish. The poison helps the mollusk cope with a large prey. It can also be dangerous for humans.
Although octopuses have great strength, they get tired pretty quickly. They cannot hunt for a long time, their muscles weaken after a few minutes. If an octopus swims about 20 meters several times, then it freezes exhausted on the seabed. There is an explanation for this: there is no hemoglobin in the blood of these mollusks, and oxygen transfer is carried out using the hemocyanin pigment, which contains iron and copper. Hemocyanin does not carry oxygen very well, although the mollusk has a well-developed circulatory system and there is an additional heart, during prolonged exercise, the supply of oxygen to the muscles decreases.
Octopus mating
The mating process in these marine animals is also quite interesting. Sperm containers, called spermatophores, are found in males in the mantle cavity. During the breeding season, they are carried out of the funnel by jets of water. The shape of the spermatophore can be completely different. Spermatophores in an ordinary octopus reach 115 centimeters. The male holds the female during mating with one of eight tentacles, and with the sexual tentacle he takes the spermatophores from his mantle cavity and transfers them to the partner's cavity.
Small argonaut octopuses have an interesting device that facilitates the mating process. In a special bag, they form a sexual tentacle, which is located between the second and fourth hands. When the tentacle matures, it detaches from the body of the octopus and swims away in search of a female. When a female is in sight, the tentacle penetrates into her mantle cavity, where the spermatophores are opened and the eggs are fertilized. That is, male argonaut octopuses do not have to break away from their usual activities for mating.
Females lay long oval-shaped eggs in their shelters and carefully guard their future offspring. The debugging process takes place in the following way. The eggs exit the pouch through a funnel, which is bent between the tentacles, then they attach to the suckers. And then the female performs jewelry work - she attaches each egg with a thin leg to the surface of the nest.
During the incubation of eggs, the female is constantly in the shelter and closes the clutch with her body. This process takes many weeks - sometimes up to 4 months. Throughout the process of incubation, the female takes care of her eggs - she cleans them of dirt and rinses with water. As a rule, during this period, females do not eat, so as not to pollute the water around the nest, since the eggs are especially sensitive to the purity of the water. All organic matter the mother is thrown away from the nest by a strong jet of water. When the eggs hatch, many females are completely emaciated and some of them fail to survive. And other females keep the eggs in their tentacles all the time, as if in a basket.
Newborn octopuses are only a few centimeters long. But on appearance they are identical to adults. At first, their diet consists of the smallest crustaceans. After about a year, the cubs of some species of octopuses exceed 10 centimeters in length. They are difficult to detect at the bottom of the sea, they hide in various shelters, among stones, in shells. bivalves and even in bottles that fell on the seabed.
These mollusks lend themselves perfectly to training, in general they are considered the most intelligent among other invertebrates. They can distinguish geometric shapes like dogs or elephants. If pieces of food are lowered into the aquarium to the octopus, to which a figure in the form of, for example, a white square is attached, then after several experiments the mollusk will rush to the white square without food. During such experiments, for the correct decision, the octopus received an additional portion of food, and in case of an error, it was hit with a slight electric shock. Studies have shown that octopuses can distinguish between squares and triangles, and between vertical and horizontal rectangles. They can also distinguish colors. In addition, they manage to determine the size of the figure, for example, they can distinguish a square with a side length of 4 centimeters from a square with a side length of 8 centimeters. The acquired skills are stored in mollusks for many weeks.
Interesting studies were carried out to study the spatial vision of octopuses and the ability to determine the trajectory of movement. For this, the crab was placed in a glass vessel, into which the octopus could only get along the corridor, turning left or right. The prey was placed either on the left or on the right, alternately. Octopuses quickly figured out how to choose the right direction and reach prey, even when moving along a darkened corridor.
In one experiment, a crab was hung on a string from a cork, placed in a bottle, and shown to an octopus. The end of the thread stuck out a little from under the cork. The octopus opened the lid, and the crab was pulled by a string. Octopuses living nearby can distinguish their neighbor from other relatives. If octopuses are kept in an aquarium, then they can remember the faces and people who take care of them and feed them.
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Octopus - squad representative sea shellfish belonging to the class of cephalopods. All individuals are characterized by a sac-like body. Further in the article we will find out the features of these animals, how many legs an octopus has. Photos of shellfish will also be given below.
Short description
The octopus has three hearts. The main thing is to move blood around the body. The rest push it over the gills. Due to the fact that hemocyanin is present in plasma and red blood cells (copper replaces iron in it) instead of hemoglobin, the blood of animals is blue. The octopus has large eyes with a rectangular pupil. The head of the animal is well developed, has a cartilaginous skull. It provides protection to the brain with a rudimentary cortex. The size of the animal is from 50 mm to 9.8 m (between the ends of the tentacles located oppositely).
Nutrition
All octopuses are predators. Their main food is crustaceans, fish, and molluscs. The common octopus captures prey with all its tentacles. Holding the victim with suction cups, he bites her with his beak. Poison from the salivary glands enters the wound of the prey. Octopuses are characterized by pronounced individual preferences in food and methods of obtaining it. The mollusk has four pairs of tentacles. How many legs an octopus has and whether it has hands, we will find out further.
Shellfish in motion
Most species live among stones, algae and rocks. A favorite hiding place for young animals in the Far East, for example, are empty scallop shells. Due to the fact that octopuses are more active at night, they are counted. So, how many legs does an octopus have? How does he even use his limbs? On solid, including sheer surfaces, molluscs move by crawling. In this case, all tentacles are involved. Many people think that an octopus has eight legs. However, this is not quite true. During research, it was found that the mollusk is repelled by two tentacles. To move forward, he uses the rest of the limbs. Movements "hands" are similar to those that swimmers make. A pair of hind limbs is used to move along. With their help, the mollusk also climbs underwater rocks. Thus, the number of legs in an octopus is 2, all other tentacles perform the function of hands. Due to the fact that the body of molluscs is elastic, they can penetrate through cracks and holes, the dimensions of which are much smaller than their own. This allows them to hide in all sorts of shelters.
Behavior
Many species have special glands that produce a dark liquid called "ink". In the form of translucent shapeless spots, the liquid hangs in the water and keeps compact for some time before it is washed away by water. Fleeing from someone, the octopus releases jets of ink. Zoologists today do not have a consensus about the purpose of this behavior. The researcher Cousteau put forward the hypothesis that " ink stains"In octopuses, they are in some way false targets for opponents, diverting their attention. Mollusks have another device for protection. The tentacle of a mollusk, grabbed by an enemy, can come off. This is due to a strong muscle contraction. For some time, the torn off tentacle continues to react to tactile stimuli and move.This is another additional distraction for those who are chasing the octopus.
Research
For a very long time, there was no exact answer to the question of how many legs an octopus has. Biologists from more than twenty European research centers have observed the behavior of octopuses for a long time. About two thousand data were analyzed. In the course of research, it was found that two tentacles are definitely legs. As a rule, animals move slowly. But in case of danger, mollusks can reach speeds of up to 15 km / h. The researchers note that the brain sends a signal to start moving, but each tentacle makes its own decision about its speed, character and direction. At the same time, even those limbs that are torn off from the body continue to perform the actions programmed earlier. Biologists have also found that the octopus is equally good at the limbs of the left and right sides of the body. However, preference is still given to the third front tentacle - it is intended for bringing food to the mouth. Each limb has up to 10 thousand receptors, through which the inedibility or edibility of an object is determined.
Peculiarities
After finding out how many legs an octopus has and how it uses its limbs, the researchers began to study the intelligence of animals. Animal psychologists consider these mollusks the most intelligent of all representatives of invertebrates. Such conclusions are based on practical observations. So, cephalopods have a good memory, can be trained, are able to distinguish geometric figures: large from small, circle from square, vertical rectangle from horizontal. In addition, they get used to people, easily recognize those who feed them. If you spend a lot of time with an octopus, then it will become tame. These molluscs are highly trainable.