Octopus tentacles are positioned. How dangerous is an octopus for humans? Amazing cephalopods

Their sizes can vary greatly, and there are octopuses that reach large sizes. Octopus tentacles pose a threat even to divers, although some naturalists believe that this threat is somewhat exaggerated. These mollusks swim easily, move along the bottom, and sit in their favorite underwater crevices and caves. The number of brain (nerve) cells in them is significantly increased, and they form brain centers - ganglia, which have a cartilaginous skull to protect them.

The length of octopus tentacles can reach 7.5 - 9 meters.

Octopuses- the most highly organized representatives among cephalopods and are considered extremely intelligent, if this word can be used here, animals. The highly organized nature of some cephalopods in evolutionary terms is also evidenced by the structure of their eyes. For example, the eyes of octopuses are so complex that scientists consider them similar to the eyes of vertebrates, since almost all the elements typical of vertebrate eyes are present in the eyes of octopuses. His eyes are able to adapt to changes in lighting when emerging from the depths to the surface.

Octopuses, which have a relatively highly developed brain, are quite curious, but more often, being quite cautious animals, they prefer to swim away from him when meeting a person. The real danger for swimmers is careless handling of even small octopuses, which, having a well-developed venomous apparatus, can bite.

It is believed that octopuses can develop it quite easily. There are cases when biologists, studying the capabilities of these animals, easily achieved their appearance by feeding them with fish. At the same time, the octopuses even showed some friendliness towards humans, but these were not very large specimens.

Octopus poison apparatus contains front and rear salivary glands, from which the salivary duct departs into the buccal mass and jaws. With these jaws the octopus is capable of inflicting strong bites and even tear apart captured prey held by the suction cups of the tentacles. In the animal's mouth there is a tongue, in front of which there is a growth that opens to the duct of the posterior salivary glands. The anterior salivary glands have paired ducts that open in the pharynx from the side and back. The poison from them gets into the throat of the mollusk.

The octopus's mouth opens into a pharynx with thick, muscular walls. This entire muscle complex is called buccal mass. It is well hidden in the surrounding muscular bases of the tentacles. This buccal mass is crowned with two powerful chitinous jaws, upper and lower.

In general, octopuses can be considered rather than swimming. Typically, small specimens often live close to the shore at shallow depths, but large species they live at great depths - up to 8 thousand m. The tentacles are dangerous for scuba divers and divers because, having grabbed a person, they can pull him to the mouth. There have been cases where octopuses have become attached to a rubber diving suit, but this happened more often when people tried to remove the animal from its shelter.

Troubles for swimmers are usually caused by small species of octopuses, among which is the smallest of the octopuses that lives in the waters Australian mainland. This tiny octopus fits easily in the palm of your hand, but should be handled with great care, as its venom is highly toxic and a person stung can die within minutes. When a small Australian octopus bites, the venom affects the central nervous system, which often leads to death.

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

Octopus appearance

At first glance, its appearance may be puzzling. But in the end everything turns out to be simple and clear, where he is and what parts of his body are located. The body itself is shaped like a bag and is called the 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 a beak. With the help of this beak, octopuses grind food, because they cannot swallow it whole. In addition, a little further in the throat, they have a special grater. With this grater, octopuses grind food that has not yet been chewed with its beak into pulp. The anus is hidden under the mantle.

There are tentacles around the mouth, of which there are always 8 pieces. The tentacles of the octopus are very long and with muscles, and are covered below big amount suckers different sizes. Suckers are located on the tentacles in 1-3 rows. With one suction cup alone, due to the work of the muscles, without taking into account adhesion, the octopus can hold approximately 100 grams of weight. The tentacles are united by a small membrane 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 pushing off the water and moving around.

Under the eyes of the octopus is siphon, which looks like a short tube or small hole. Using a siphon, water is drawn into the mantle cavity. Using the contraction of the mantle muscles, the octopus forcefully pushes water out of the mantle cavity, 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 water, octopuses move by crawling, using tentacles.

They have blood blue color due to hemocyanin. This is a special pigment that replaces hemoglobin. Gills are hidden in the mantle cavity and are necessary not only for breathing, but also for excreting waste products. They also have a special ink sac that accumulates a protective coloring substance.

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

Due to the lack of bones, these animals can easily change shape and stay in confined spaces.

Octopus sensory organs

Among invertebrates Octopuses are considered the most highly intelligent. All their senses are highly developed. The most perfect among the body parts are the eyes. They are 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. The octopus sees its own image with each eye. But if necessary, in order to look at something more closely, they can bring their eyes closer and focus on the object.

Corner vision their bulging eyes almost extend to 360 degrees. The eyes contain a lens with an outward oriented retina. The shape of the pupils is rectangular. The skin is all covered with light-sensitive cells, by which they can determine which direction the light is coming from.

Taste receptors are located on the suction cups, on the tentacles. They do not have special organs for hearing, but they have the ability to hear infrasounds. Their skin is usually 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 in 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 when angry it can turn red or even blacken.

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

These animals bear offspring only once in their lives. The periods when they breed fall in April and October. In some cases, the dates are shifted and fall into 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 " hectocotylus".

Using his new organ, the male transfers the reproductive cells into the mantle cavity of the female. After this, the female lives for several more months ordinary life. Only after a long time does she begin 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 towards her future children. Sometimes the female has to wait up to 4 months for the larvae to appear. All this time she does not leave the eggs, cleans them of debris and protects them from other sea animals. It often happens that a female, exhausted from hunger, cannot stand it and dies. Males, after they pass on male reproductive cells, also die.

Larvae that hatch from 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

Based on their feeding method, benthic species can be classified as lurking predators. They use this type of hunting, since octopuses are not adapted to move or swim quickly. 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 suddenly rush at them, enveloping them with their tentacles. So that you can’t escape anymore.

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

All species of these cephalopods belong to predatory animals. Before eating their prey, they capture it with their tentacles and kill it with poison. Animal shells are broken by the beak, which is located near the mouth. Also, each octopus has very distinct 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. a larger individual.

If the octopus senses or notices an enemy, it will first try to defend itself. Firstly, it will try to “escape” on half-bent tentacles or slowly swim away. If he is scared, he can jerkily increase his speed up to 15 km/h. Then it will look for somewhere to hide or camouflage itself by changing its color. They camouflage themselves into the surrounding landscape even when they are not in any danger. If the soil is soft, they bury themselves in the sand. If the fear 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 it is grabbed and there is no way to escape.

The octopus is an amazing inhabitant of the underwater depths. It got its name from the Greek words ὀϰτώ and πούς - eight and leg, respectively, in Latin - Octōpoda. Lives in the most different seas and oceans, more often in warm, tropical and subtropical ones. But some representatives feel good in colder waters (Atlantic, Far East, found even in the Arctic). There are about 300 different species in nature. The smallest individuals grow only up to 4 cm, the largest - up to 4 meters. There is evidence of giant specimens from the Doflein genus measuring about 10 m (960 cm) and weighing 270 kg. A lot is known about the order Octōpoda; they are unique creatures. But who are they, fish or animals? It will help answer this question official science– zoology.

Who are octopuses

To determine exactly what octopuses are (they are also called octopuses) and find out which group they belong to, you need to remember general rules classification of all living beings. This is done by a special science – systematics. Based on similar characteristics, all living beings are united into kingdoms, which are divided into types. Those, in turn, are divided into classes, orders, species and genera. Genus - the lowest systematic unit, similar in a number of characteristics of the genus are combined into species. Many factors are taken into account when determining a specific position in the classification table.

Animals, from a taxonomy point of view, are all multicellular organisms that move and feed on plants or other animals. An octopus is clearly an animal; its body is multicellular and complex. The other criteria are also suitable: it moves well, not only in water, but also on land. And it is a predator - it hunts other fish, crabs and various sea ​​creatures.

Then the division into types begins. The subkingdom of multicellular organisms is divided into main groups according to a certain characteristic, depending on the complexity of the structure of their organism. Chordates, those with a skeleton, are considered complex from an anatomical point of view. Its absence provides grounds for inclusion in another group. For example, fish have a skeleton, but octopuses do not. They are accordingly included in different types. Fish are chordates, octopuses are molluscs. Despite the fact that they live in the same element, this is already different groups, therefore octopuses are definitely not fish. Although they have a similar feature: they breathe oxygen dissolved in water through their gills. But gills are not the characteristic by which these two types can be combined into one.

Chordata are divided into classes. The class of mammals has the most complex structure of the body. It is grouped according to its main characteristic – the method of feeding offspring. If it is fed with milk, the animal is uniquely assigned to this class, regardless of the method of movement, habitat, size and appearance. For example, marine life dolphins are mammals. But octopuses do not belong to this class. First of all, they aren't even chordates. Secondly, they do not feed their offspring milk.

The place of octopuses in the classification table is as follows:

• kingdom: animals;
• type: shellfish;
• class: cephalopods;
• squad: octopuses.

Next comes the division of genera and species. Despite the difference in size, external signs and habitat, all representatives of the octopus order have the same structure, principles of nutrition, reproduction and other unifying characteristics. So, big octopus Dofleina's body structure is not fundamentally different from the mini version - the species Argonauto argo, the adult male of which is only 1 cm in length.

Interesting fact: the Doflein giant is amazing in its size. But after birth, mollusks of this species do not exceed 4 cm.

Amazing cephalopods

So, everything is clear with the classification from a systematic point of view. Octopuses are invertebrates classified as a separate class - cephalopods. But if we consider octopuses from the point of view of their similarity with other representatives of the fauna, then we can find many unifying characteristics.

Surprisingly, cephalopods have similar features to the most different representatives fauna:

• They have gills, just like fish. And in the oral cavity there is a beak, which is similar to the beak of a parrot.
• They can change color like chameleons. And to disorient predators, they release a protective cloud of ink, like their closest relatives - cuttlefish.
• In case of danger, they are ready to “give the enemy” their leg and grow a new one (like a lizard’s tail).
• They have the ability to mimicry, imitating the environment, objects, and other marine inhabitants, for example, like praying mantises. And in case of danger, they depict exactly the predator that will scare off the attacker ( different types are able to depict copies of 24 species of marine organisms, from jellyfish to stingrays and sea snakes). Octopuses are capable of depicting very unusual objects. Thus, a case was recorded when a caught octopus copied the newspaper on which it was placed.
• They can move on land for some time, that is, live in two environments like amphibians: octopuses have a special reservoir for water, it is located in the mantle cavity, the supply of oxygen lasts for an average of 4 hours.
• They perceive ultrasounds as the bats and dolphins. Despite the lack of ears, they hear quite well, like many land animals.
• They are tamed, trained, able to distinguish between pictures and people, and perform simple tasks; their intelligence is determined at the level of dogs and crows.

• They have a developed sense of direction: being on land, they perfectly determine the shortest distance to the sea. This instinct is somewhat reminiscent of the ability to navigate in migratory birds. Some species travel across seas and oceans, but return to a specific area to reproduce, like fish to spawn.
• Have quite sharp vision, the overview can cover 360 0 . These mollusks have the rudiments of binocular vision.
• Cephalopods kill their prey with poison (it is usually not dangerous for people, with the exception of poison in representatives of the genus Blue-ringed, which has a nerve-paralytic effect). The poison contains substances that can soften the crab's shell. This mechanism is reminiscent of the feeding pattern of some spiders; their enzymes dissolve the chitinous membranes of insects. And it has a paralytic effect; similar enzymes are often found in the digestive tract of predators.
• They take care of their offspring. In nature, parental instincts are not uncommon, especially in highly organized organisms. Female octopuses guard the clutch of fertilized eggs, while they themselves refuse to feed during this time and can starve for 4 months (usually dying as a result). Which is reminiscent of the “diet” of male penguins, who hatch a single egg and go without food during this entire period.

These amazing octopuses live in sea ​​depths! In their arsenal there are different mechanisms that are typical for other representatives of the fauna. Octopuses are also capable of:

• hold food with the power of suction cups, each of which is capable of holding any object weighing 100 g;
• excellent at identifying edible and inedible objects using taste buds located on the tentacles;
• clean your home, throwing out garbage and putting it in garbage heaps;
• regulate heart rate depending on water temperature;
• adapt to environmental conditions: shining example– replacement of the ink cloud of deep-sea inhabitants with a cloud of luminous symbiotic bacteria, which in the darkness at depth blinds the enemy;
• transform its leg into a reproductive organ: one tentacle of the male becomes a hecocotylus containing sperm, depositing sperm into the mantle of the female (and in some, the hecocotylus breaks away from the body and independently fertilizes her).

A few more facts:

• Cephalopods have 3 hearts, one ordinary, three-chambered, and two small gills;
• their blood is blue due to hemocyanin, which replaces hemoglobin;

A more or less close acquaintance with octopuses became possible thanks to the advent of high-quality scuba gear. So, with the help of a cylinder with a breathing mixture and a wetsuit, a person learned that the octopus is a sensitive, timid creature and does not tolerate unnecessary fuss.

An outwardly unattractive marine animal, which has 8 wriggling tentacles on its head with hemispherical suckers and sensitive antennae (cirrhi), a short sac-like body, a curved beak and cold, unblinking eyes, has a well-developed nervous system. It is known that octopuses have high intelligence and an extraordinary sense of parental duty.

These representatives of cephalopods form two suborders: deep-sea octopuses (Cirrata) and true octopuses (Incirrata). The size of most octopuses does not exceed half a meter; only the common octopus, Apollyon, Hong Kong and Doflein octopus are considered large. Some species are poisonous. They live in subtropical and tropical seas and oceans, most often in coastal rocky areas. They feed on crustaceans, mollusks and fish. Octopuses breathe through gills and can remain out of water for a short time.

The tentacles of the octopus are connected by a thin membrane, which when opened forms an umbrella. The organs of touch are long thin antennae, with the help of which the octopus controls the space in front of itself. Due to the absence of bones, the gelatinous, jelly-like animal easily changes shape, which helps it hide from pursuing predators. In addition, the skin common octopus contains a special pigment with which the monster changes color, adapting to its environment. Because of their blue blood, which contains hemocyanin instead of hemoglobin and copper instead of iron, octopuses are often called the “aristocrats of the sea.” The animal has three hearts: the main one drives blood throughout the body, and two gills push it through the gills. Octopus has big eyes with a rectangular pupil and a human-like lens.

Animals Through the Lens: Octopus (1982) (film)

A giant octopus attacked a cameraman / Animal attacks on people

Octopus: bizarre inhabitants of the deep sea

Octopuses represent the class of cephalopods (Cephalopoda) known for their intelligence, uncanny ability to blend in environment, unique style of movement ( jet propulsion), as well as splashing 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). Fin fish 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 best known species of octopuses, most of which are benthic.

2. Octopus tentacles are called arms

The average person won't see the difference between tentacles and arms, but marine biologists clearly separate these two concepts. The arms of cephalopods are covered with suction cups along their entire length, and the tentacles have suction cups only at the tips and are used to capture food. By this standard, most octopuses have eight arms and no tentacles, while two other 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 simply serves as a visual distraction to buy the octopuses time to escape, but it also affects the predators' sense of smell (sharks, which can smell hundreds of meters away, are especially vulnerable to this kind of 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 images. But regardless of octopus intelligence, it is very different from human intelligence: 70% of an octopus's neurons are located along the length of its arms, not in its brain, and there is no conclusive evidence that these are capable of communicating with each other.

5. Octopuses have three hearts

All vertebrates have one heart, but octopuses are equipped with three: one that pumps blood throughout the octopus's body (including the animal's arms), and two that pump blood through the gills that they use to breathe underwater. There is another key difference from vertebrates: the main component of octopus blood is hemocyanin, which contains copper atoms, rather than iron-containing hemoglobin, which explains the blue color of octopus blood.

6. Octopuses use three modes of locomotion

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

7. Octopuses are masters of camouflage

Octopus skin is covered with three types of specialized cells that can quickly change color, reflectivity and transparency, allowing the animal to blend into its environment. 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 camouflage. Thanks to this arsenal of cells, some octopuses are able to disguise themselves as algae!

8. The giant octopus is 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 sink large ships. The biggest known species octopus - giant octopus (Enteroctopus dofleini), weighs on average about 15 kg, and the length of the arms (tentacles) is about 3-4 m. However, there is some dubious evidence of significantly larger individuals giant octopus, weighing more than 200 kg.

9. Octopuses have a very short lifespan

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

10. The octopus order has another name

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

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