What is the head of an octopus called? Octopus is an amazing shellfish

Diving in warm and temperate seas, divers may be lucky enough to see an extremely interesting animal - an octopus. Of course, everyone has heard and knows about this inhabitant. sea ​​waters, but the details of the lifestyle of octopuses, species diversity and body structure are far from known to many.
The purpose of this article is to shed a ray of light on some of the shady, for most of the world's population, aspects of octopus life.

Let's start with the fact that octopuses belong to a subclass of intrashell (also called double-gill) cephalopods ( Coleoidea).
The main sign of representatives of this subclass of mollusks is the presence of an internal shell, which is difficult to call a shell - just a remnant (rudiment) of the shell that covered the body of the distant ancestors of these mollusks. These ancient mollusks died out long ago, leaving behind only one tiny detachment of modern cephalopods - nautiluses, which still have an outer shell.

The name "cephalopods" was assigned to these molluscs, including octopuses, because they have limbs on their heads - tentacles, sometimes called arms or legs. With the help of these "arms" or "legs" (as you prefer), cephalopods catch and hold food, can move (even along the bottom), build and equip their dwellings, and do many other things. beneficial actions. The main purpose of the tentacles, of course, is to capture food and deliver it to the mouth.
The octopus, as the name suggests, has eight tentacle legs.

From the shell that once covered the body of a distant ancestor of octopuses, only cartilaginous formations in the form of sticks or curved plates supporting the fins remained. Some species of octopuses do not even have such a remnant of the shell - it has completely disappeared as unnecessary.

Octopuses appeared, apparently, in the early Mesozoic. In any case, the primitive representatives of this order have been known since jurassic. In the squad of octopuses ( Octopoda) there are about 200 species that form two suborders : finless or real octopuses (incirrata) and finned octopuses (Cirrata).
This article describes the structural features of finless (real) octopuses, since representatives of the second suborder live in the dark depths of the ocean, inaccessible to the eyes of divers and divers, so it will not be possible to meet them during the dive.
But do not worry too much about this - the main structural features of the representatives of both suborders are similar.
The main external differences are the presence (as you probably guessed by the name) of fins, as well as webbed jumpers between the tentacles, which are almost to the tips of the tentacles in fin octopuses, the absence of an ink sac in fin octopuses (why is there ink in the dark?) and some others features.

Now - external signs real (finless) octopuses .
The body of octopuses is soft, oval in shape, dressed in a skin-muscle bag (or, if you like, a mantle), which contains internal organs. The mantle is smooth, with pimples or with folds at different types octopuses, more often it resembles a wrinkled bag.
The head of an octopus is fused to the mantle. Eyes are located on the head, often very large, especially in deep-sea species. The tentacle arms are also placed here, crowning the mouth of the octopus.

The inner surface of the tentacles is covered with several rows of suckers, which are smaller at the base and on the tips of the tentacles, and large in the middle part. With the help of suction cups, the octopus can capture and hold prey, as well as attach itself to underwater objects. One suction cup of a large octopus is able to hold a load weighing about 100 grams. If we take into account that the number of suckers on one "arm" can reach up to 220 pieces, then we can calculate the weight that each limb of an octopus can hold.
In addition, taste and tactile receptors are located on the suckers (up to 50-60 pieces on each), so we can say that octopuses distinguish the taste of food with the help of tentacles. Another detail - in sexually mature males, one "hand" is transformed into a copulatory organ - hectocotylus, with which he transfers the reproductive products to the female's seminal receptacle.

The tentacles of octopuses are subject to the most frequent attacks of enemies, as they constantly move around the owner's shelter and feel objects that are nearby. Therefore, nature has provided octopuses with the property of autotomy - the ability to tear off pieces of their flesh (in this case, tentacles) in case of need and danger. The tentacle captured "captured" sharply and strongly contracts, as a result of which it breaks. The torn off piece of the "arm" of the octopus wriggles and swims autonomously, distracting the enemy from its former owner.

The mouth of octopuses is small, the pharynx is muscular, equipped with a pair of strong chitinous jaws, resembling the beak of a parrot and often called the "beak".
AT oral cavity there is a special tongue outgrowth - odontophore, on which a radula is placed - a chitinous ribbon, seated with small teeth. With the help of the radula, food that has entered the mouth of the octopus and moistened with saliva from special glands is ground and transported to the esophagus, which in the form of a thin tube stretches from the pharynx to the stomach.
On the way to the stomach, the esophagus passes through the brain and liver of the octopus. Since the esophagus is very thin, octopuses cannot swallow prey whole and are forced to crush it into small pieces with their "beak" before sending it to the mouth.
Once in the stomach, food is digested with the help of digestive juices produced by the liver and pancreas. The activity of the enzymes of these glands is very high and in 3-4 hours the food is completely digested. Then useful material absorbed into the body of an octopus with the help of a process of the stomach - cecum and with the help of the liver.
Undigested food remains are expelled through the intestines.
The octopus liver is a large oval brownish organ that performs several functions. It produces enzymes, absorption of amino acids occurs in it, it is also the custodian of the supply of nutrients.
This is the digestive tract of an octopus.

Almost all octopuses (except for some deep-sea species) have an ink sac with a duct in the abdominal cavity that connects the sac to the intestine. I will tell you about the contents of this bag - ink on a separate page of this site.

In the upper part of the mantle cavity there is a pair of gills - one on each side of the body of the octopus. Their function is to extract oxygen from the water.
Octopuses have a highly developed circulatory system. Circulatory system they are almost closed. The skin and muscles in many places are supplied with capillaries through which arteries pass into veins.
Blood is driven by three hearts - the main one, consisting of the ventricle and atrium, and two branchial hearts. The main heart drives blood through the body of the octopus, and the rhythmic contractions of the gill hearts push venous blood through the gills, from where it, enriched with oxygen, enters the atrium of the main heart.
The heart rate of an octopus depends on the temperature of the water - than colder water, the less the beat. So, at a water temperature of 22 degrees C, the hearts contract 40-50 times per minute.
The blood of "noble" octopuses blue color due to the presence in it of the enzyme hemocyanin containing copper oxides.
Only due to the presence of a highly developed circulatory system and the presence of capillaries, some species of octopuses can reach gigantic sizes.
The largest octopus caught is Doflein's Pacific octopus ( O.dofleini), whose tentacle span was 9.6 meters and weighed 272 kg.

The organs of excretion in octopuses are the kidney sacs, the appendages of the gill hearts, and the gills themselves. the main metabolic product, like in all cephalopods, is ammonia (more precisely, ammonium ions).

The nervous system of octopuses is very developed and more complex than that of other invertebrates. In terms of complexity and level of organization, it is not inferior to the nervous system of fish.

Nerve fibers - ganglia are very close and, in essence, form a single nerve mass - the brain, which is enclosed in a cartilaginous capsule - the skull. The brain consists of lobes, of which the octopus has 64 and has the rudiments of the cortex. The largest and most numerous lobes are optical, their volume can be up to 4/5 of the entire brain volume.
In terms of subtlety of feelings, accuracy of perception and complexity of behavioral reactions, octopuses are superior to many marine animals. They tend to good memory They are well trained and trainable.

Among the sense organs of the octopus, the eyes have reached the greatest perfection. in form and appearance they are surprisingly similar to human eyes, not only in structure, but even in expression.
The eyes are usually located in the recesses of the cranial cartilage capsule and have a cornea, an iris with a rectangular pupil capable of contracting and expanding, a lens and a retina. In general - everything, like people! True, setting vision at different distances (accommodation) in an octopus is achieved by changing the distance from the pupil to the retina, and in humans - by changing the curvature of the lens.
The eyes of the octopus are very sensitive and surpass the eyes of many marine animals in this indicator. In 1 sq. mm of the retina of an octopus, there are up to 64 thousand light-sensitive elements, while, for example, in carp - 50 thousand.
Usually octopuses see with each eye separately, while their horizons can reach 300 degrees. However, when he needs to consider something in detail, he raises and brings his eyes together and looks both in the same direction. Some deep-sea octopuses have eyes that sit on stalks like periscopes.

Like most cephalopods (except nautilus), octopuses perceive light not only with their eyes, but also with the help of special, inherent and in many ways still mysterious organs - extraocular photoreceptors. In octopuses, they are usually small orange or yellow formations - light-sensitive bubbles located on the inside of the mantle.
Octopuses can also perceive light with the help of skin photosensitive cells, which play a large role in changing the color of the body.

The sense of taste and touch in octopuses is also very developed, they can even "see" enemies with the help of taste buds located on the suction cups of the tentacles.
Once, a drop of water taken from an aquarium with moray eels was released from a pipette into an aquarium with an octopus - worst enemy octopuses, he was frightened, turned purple and took to his heels.
The olfactory pits are the organs of smell in octopuses.

In the occipital part of the cartilaginous skull of an octopus there is a pair of statocysts - balance organs, which are bubbles filled with liquid and having calcareous stones inside - statoliths. When the position of the body of the octopus changes in space, the statolith stones touch the walls of the statocysts and irritate the sensitive cells that are located on the walls of the bubble. Thanks to this, the octopus is oriented in space even in the absence of lighting.

As for the hearing organs, they are in their infancy in octopuses, in some species it seems to be absent altogether. At least, attempts to develop reflexes to sound stimuli in octopuses have not been successful.

Octopuses, like many cephalopods, can surprisingly quickly and harmoniously color their body to the color of the environment, and even the deceased, he does not immediately lose this ability.
This property of cephalopods is explained by the presence in their skin of cells with various pigments, which, under the influence of impulses from the central nervous system stretch or shrink depending on the perception of the senses. The usual color of the common octopus ( O. vulgaris) - brown. If you scare an octopus, it will turn white, if angry, it will turn red.

The English writer D. Aldridge, a great lover and connoisseur of spearfishing, described in his book "Spearfishing", published back in 1960, such a case:
"... once I managed to shoot a small octopus, I brought the prey ashore and put the killed octopus on a newspaper sheet for cutting. The killed octopus instantly changed color and became striped - dark and light stripes on its body imprinted lines on a newspaper sheet.
Perhaps this octopus was not yet completely dead and its eyes perceived the light ... "

The change in body color in octopuses occurs according to the same principle as in virtuosos in this art - cuttlefish. More detailed description you can find the mechanism of this ability of cephalopods.

Octopuses are separate sexes, that is, there are female and male individuals of these animals. Sex products in males are enclosed in special packages - spermatophores, which have a complex structure and different shape in different types of octopuses. Typically, octopus spermatophores are shaped like a thin, slightly curved tube, but in the largest octopuses they can reach a length of almost 1 m (Dauflein's octopus). Spermatophores are formed in a special section associated with the testes, consisting of several glands and ducts.

The mating of octopuses occurs as follows: spermatophores go out through the excretory canal and are picked up by the hectocotylus, a modified tentacle of a sexually mature male octopus. The hectocotylus then transfers the spermatophores to the female's seminal receptacle, where the eggs are fertilized.
An interesting method of fertilization in small pelagic octopuses from the group Argonautoidea- tremoctopuses, argonauts. On the head, in a special bag, these octopuses have a very large hectocotylus, which then breaks off and, having captured the spermatophore, swims away, wriggling, in search of a female of its own species. Having found a female, he penetrates into her mantle cavity, where the content of the spermatophore "explodes" and fertilizes the eggs.

After fertilization, the female octopus makes a nest in a hole or cave in shallow water, where she lays up to 80,000 eggs. The nest is a hole in the ground lined with a shaft of stones, shells and other rubbish.
Eggs are spherical or oval, small, connected in groups (8-20 pieces each). Usually the female takes care of the eggs: she constantly brings fresh water to them, removes foreign objects and dirt with her tentacles. During the entire period of egg development, the female remains at the nest.
After a few months (usually 2-4), larvae hatch from the eggs, which for the first time (1.5-2 months) live in the surface layers of water, feeding on benthos. As they grow older, young octopuses move to a bottom-dwelling lifestyle and quickly grow into adult octopuses. The mortality of juveniles is very high - only a few individuals out of hundreds of thousands of larvae survive to sexual maturity.
The female and male octopuses do not feed after copulation and soon die, giving life to a new generation.

Below is a short video about octopus cephalopods.

Octopuses are animals related to cephalopods. In the order of animals "octopuses" 200 various kinds. Their closest relatives in this type are squid and cuttlefish. The most distant include all gastropods and bivalves.

Appearance of an octopus

At first glance, its appearance may be puzzling. But in the end, everything turns out to be simple and clear where he has and what parts of the body are. The body itself is similar in shape to a bag and is called a mantle. In front, it is connected to a large head with two bulging eyes located on it. Their mouth is very small. Around the mouth chitinous jaws, which are called the beak. With the help of this beak, octopuses grind food, because they cannot swallow it whole. In addition, a little further down the throat, they have a special grater. With this grater, octopuses grind food that has not been chewed with their beak into gruel. The anal opening is hidden under the mantle.

Around the mouth are tentacles, of which there are always 8 pieces. The tentacles of the octopus are very long and with muscles, and from below they are covered with a large number of suction cups of various sizes. Suckers are located on tentacles in 1-3 rows. With one suction cup, only due to the work of the muscles, without taking into account sticking, an octopus can hold about 100 grams of weight. Between themselves, the tentacles are united by a small membrane, which is called the umbrella. About 20 existing species Octopuses have small fins on both sides. In these species, the fins are used as a rudder, and not for repulsion from the water and movement.

Under the eyes of an octopus is siphon, which looks like a short tube or small hole. With the help of a siphon, water is drawn into the mantle cavity. Using the contraction of the muscles of the mantle, the octopus pushes water out of the mantle cavity with force, which moves its body. To change direction, he turns the siphon and pushes the water in the other direction. On a hard or vertical surface in the water, octopuses crawl using tentacles.

Their blood is blue due to hemocyanin. This is such a special pigment that replaces hemoglobin. The gills are hidden in the mantle cavity and are necessary not only for breathing, but also for excreting decay products. They also have a special ink bag that accumulates a coloring protective substance.

The largest octopuses grow up up to a length of 3 meters and 50 kilograms of weight. The most common species are from 0.2 to 1 meter in length. The only exceptions are males from the Argonaut species. They are much smaller than the females of their species, rarely growing even to a length of 1 cm.

Due to the lack of bones, these animals can easily change shape and be in a limited space.

Sense organs of an octopus

Among invertebrates Octopuses are considered the most highly intelligent. All of their senses are highly developed. The most perfect among the parts of the body are the eyes. Not only large in size, but also very difficult to work with. Fundamentally, the method of image formation in the eyes of an octopus and a person does not differ. Each eye of the octopus sees its own image. But if necessary, in order to take a closer look at something, they can bring their eyes closer and focus on the object.

Corner vision their bulging eyes nearly reach 360 degrees. The eye has a lens with an outward-oriented retina. The shape of the pupils is rectangular. The skin is covered with light-sensitive cells, by which they can determine from which direction the light is directed.

Taste receptors are located on the suckers, on the tentacles. They do not have special organs for hearing, but they have the ability to hear infrasounds. Usually their skin is brown, red or yellow. Although, depending on the situation, they can change skin color like chameleons. The principle of color change is the same as that of reptiles. The current color is directly dependent on the well-being or mood of the animal, as well as on the environment. When frightened, his skin becomes paler, and in anger it can turn red or even blacken.

An interesting fact is that the change coloring has a direct relationship with visual perception. If you blind an octopus, it will lose the ability to change color. If you blind him in one eye, then he will change color only on the side of the body on which he sees. The tactile photosensitive cells on the skin also play a small role.

These animals bring offspring only once in a lifetime. The periods when they breed are April and October. In some cases, the dates are shifted and fall on June and October. Although they live on average no more than 2 years. Some time before the mating season in males, one of the tentacles transforms into an organ necessary for reproduction. This organ is called hectocotyl".

Using his new organ, the male transfers the germ cells into the mantle cavity of the female. After that, the female lives for several more months. ordinary life. Only after a long time she begins to lay eggs. In one clutch there may be a large number of eggs: from 40 to 190 thousand pieces.

After laying eggs, the female becomes the most caring animal in relation to her future children. Sometimes up to 4 months the female has to wait for the appearance of larvae. All this time, she does not leave the eggs, cleans them of debris and protects them from other marine animals. It often happens that a female, exhausted from hunger, cannot stand it and dies. Males, after transferring male germ cells, also are dying.

The larvae that hatched from the eggs are already independent from the first days of life.

What do octopuses eat

Basic food for octopuses are the following types of marine animals:

1. Fish;
2. crustaceans;
3. shellfish.

The demersal species, according to the way of feeding, can be attributed to predators of the lurking type. They use this type of hunting, since octopuses are not adapted to move quickly or swim. Hiding in a secluded place, they wait with great patience for some fish, crab, lobster or lobster to swim nearby. Then, at the right moment, they sharply rush at them, covering around with their tentacles. So no more getting out.

Kamchatka crabs are their favorite food. Having caught a crab, the octopus clamps it with tentacles from all sides, and takes it to its shelter. There are times when an octopus manages to catch and drag several crustaceans to itself at once. They also prefer to hunt gobies and flounders. Using suction cups on the tentacles, they capture prey. One sucker with a diameter of about 3 centimeters, can withstand 3 kilograms. And since the octopus has hundreds of these suckers, the strength will be great.

All species of these cephalopods belong to predatory animals. Before eating their prey, they capture it with tentacles and kill it with poison. The shells of animals are broken by the beak, which is located near the mouth. Also, each octopus strongly distinguishes its own preferences in food and in the methods of obtaining this food.

The main enemies of octopuses

The main enemies include the following animals:

1. Dolphin;
2. sea ​​lion;
3. seal;
4. moray eel;
5. shark;
6. bird;
7. larger individual.

If the octopus senses or sees an enemy, it will first try to defend itself. Firstly, it will try to "run away" on half-bent tentacles or slowly swim away. If he is frightened, he can jerkily increase his movement speed to 15 km / h. Then he will look for where to hide or disguise himself by changing color. They disguise themselves as the surrounding landscape even when they are not in any danger. If the ground is soft, then they burrow into the sand. If the fright is very strong, then a dark-colored liquid is released, with the help of which the enemy is disoriented. Can sacrifice a tentacle to an enemy if grabbed and there is no way to escape.

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. At the octopus big 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).

Food

All octopuses are predators. Their main food is crustaceans, fish, and molluscs. 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 on 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 have no consensus about the purpose of this behavior. Researcher Cousteau hypothesized that "ink spots" in octopuses are in some way false targets for opponents, diverting their attention. Mollusks have another adaptation for protection. A clam tentacle that is grabbed by an enemy can break off. This is due to strong muscle contraction. For some time, the severed tentacle continues to respond to tactile stimuli and move. This is another additional distraction for those chasing the octopus.

Research work

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, nature 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.

Octopuses are a class of cephalopods. (Cephalopoda) known for their intelligence, supernatural ability merge with environment, unique movement style ( jet propulsion), as well as splash ink. On the following slides, you will discover 10 fascinating facts about octopuses.

1. Octopuses are divided into two main suborders

We know about 300 living species of octopuses, which are divided into two main groups (suborders): 1) finned or deep-sea octopuses (Cirrina) and 2) finless or true octopuses (Incirrina). The fins are characterized by the presence of two fins on the head and a small inner shell. In addition, they have antennae on their arms (tentacles) near each sucker, which may play a role in feeding. Finless, includes many of the most famous species of octopus, most of which are bottom-dwelling.

2 Octopus Tentacles Are Called Arms

The average person won't be able to tell the difference between tentacles and arms, but marine biologists clearly separate the two. The arms of cephalopods are covered with suckers along their entire length, and the tentacles have suckers only at the tips and serve to capture food. By this standard, most octopuses have eight arms and no tentacles, while the other two orders of cephalopods, cuttlefish and squid, have eight arms and two tentacles.

3. Octopuses release ink to protect themselves.

When threatened by predators, most octopuses release a thick cloud of black ink made up of melanin (the same pigment that affects the color of our skin and hair). You might think that the cloud just serves as a visual distraction to buy the octopuses time to escape, but it also affects predators' sense of smell (sharks that can smell hundreds of meters away are particularly vulnerable to this olfactory attack).

4 Octopuses Are Extremely Intelligent

Octopuses are the only marine animals, other than whales and pinnipeds, that are capable of solving certain problems and recognizing various patterns. But regardless of the intelligence level of octopuses, it is very different from human: 70% of octopus neurons are located along the entire length of their arms, not in the brain, and there is no conclusive evidence that these are able to communicate with each other.

5. Octopuses have three hearts

All vertebrates have one heart, but octopuses are equipped with three: one pumps blood throughout the body of the octopus (including the arms of the animal), and two distill blood through the gills, with which they breathe underwater. There is one more key difference from vertebrates: the main component of octopus blood is hemocyanin containing copper atoms, and not iron-containing hemoglobin, which explains the blue color of octopus blood.

6 Octopuses Use Three Ways To Move

A bit like an underwater sports car, the octopus moves in three different ways. If there is no need to hurry, they walk along the ocean floor using their flexible tentacle arms. To move faster underwater, they actively swim in the right direction by bending their arms and body. In the event of a real rush (such as attacking a hungry shark), octopuses use jet propulsion, ejecting a jet of water (and ink to disorientate the predator) from the body cavity and away as quickly as possible.

7. Octopuses are masters of disguise

Octopus skin is covered with three types of specialized cells that can quickly change color, reflectivity, and transparency, allowing the animals to blend in with their surroundings. Pigment-containing cells - chromatophores, are responsible for the red, orange, yellow, brown, white and black colors of the skin, and also give it shine, which is ideal for masking. Thanks to this arsenal of cells, some octopuses are able to disguise themselves as algae!

8. Giant octopus, considered the largest species of octopus

Forget all the movies about octopus monsters with tentacles as thick as tree trunks that sweep helpless sailors overboard and drown them. big ships. The biggest known species octopus - giant octopus (Enteroctopus dofleini), on average it weighs about 15 kg, and the length of the arms (tentacles) is about 3-4 m. However, there is some doubtful evidence of significantly large individuals of the giant octopus, weighing more than 200 kg.

9 Octopuses Have A Very Short Lifespan

You may want to consider buying an octopus as a pet, for the reason that most species have a lifespan of about a year. Evolution has programmed male octopuses to die a few weeks after mating, and females stop feeding while waiting for eggs to hatch, and often starve to death. Even if you spay your octopuses (probably not every veterinarian in your city specializes in such operations), it is unlikely that your pet will live longer than a hamster or gerbil mouse.

10. The octopus squad has another name.

You may have noticed that in this article only one term "octopuses" was used, which is familiar to everyone and does not hurt the ear. But this detachment of cephalopods is also known as the octopus (octopus in Greek means "eight legs").

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Perhaps the most well-known representatives of cephalopods are sea ​​octopus. These animals simply amaze with the variety of their sizes: from the smallest to truly gigantic!

The body structure of an octopus

The basis of the body of octopuses is the mantle, with the help of which the mollusk moves (by a sharp ejection of water from the mantle cavity). The head of the mollusk is completely fused with the body, it has rather complex sharp-sighted eyes. The mouth of the octopus is very small, there are tentacles around it. The number of tentacles is eight. Separate types Octopuses have fins on the sides of their bodies.

An octopus is an animal with a huge heart...or rather, with a huge number of hearts. The octopus has three of them! The blood of the mollusk is completely blue. Well, just not an animal, but unique! And of course, everyone knows that the octopus has an ink sac that stores a special dye that the animal releases in case of fear or danger.

The color of these animals has yellow, reddish or brown shades. But the octopus, due to special cells, can change its color to any other. And he does it instantly! In general, octopuses are the most intelligent of all invertebrates. They have sharp eyesight, and they "hear" by picking up infrasounds, since they do not have normal hearing.

The average individuals of octopuses are up to 1 meter in length, but there are both smaller (1 centimeter) and larger (3 meters). It should be noted that males are smaller than females.

Where does the octopus live?

His habitual places to live are warm seas. In them, octopuses are located in shallow water or among reefs. The depth of their residence is up to 150 meters. But there are also deeper representatives of octopuses.

Octopus lifestyle and behavior

Octopuses are mollusks that live alone. They drive sedentary life. These animals are most active at night. They spend most of the day in their hiding place and move very little. If the octopus is located on soft ground, it will definitely burrow into the sand, so much so that only the eyes will be left to observe what is happening on the surface.

What and how do octopuses eat

Like many other cephalopods, octopuses are carnivores. They capture their food with tentacles and kill it with poison, and only then they begin to eat it inside. If the victim is caught with a shell, then the octopus breaks it with its “beak”, located near the mouth.

The main components of the octopus diet are lobsters, crabs, fish, and other shellfish.

Reproduction and offspring of octopuses

Octopuses produce their offspring only once in a lifetime. Yes, and they live, however, not so long - on average from 1 to 2 years.

Before the mating season, in males, one of the tentacles turns into a reproductive organ called a hectocotylus. With its help, the male transfers his germ cells to the mantle cavity of the female. For several months, the female continues her normal life with male sex cells inside herself, and only then, after months, does she lay her eggs. There are a lot of them in the masonry: from 50 to 200 thousand pieces!

After the female produces clutch, she becomes the most caring mother in the world! She literally blows dust particles off her future octopuses. And so, without leaving the eggs, she waits for the birth of larvae, sometimes up to four months! The body, exhausted from hunger, often cannot stand it, and the female dies. Male individuals, after the transfer of male germ cells, die.

Octopus larvae hatched from eggs are already quite independent. Apparently, nature did not foresee this in vain, because by the time of their birth, baby octopuses are left without a single parent, and there is no one to protect them.