What are the tentacles of an octopus called? Sea octopus
Octopuses are perhaps the most amazing of the mollusks that live in the depths of the sea. Their strange appearance surprises, delights, and sometimes frightens, the imagination pictures giant octopuses capable of easily sinking even large ships. This kind of demonization of the octopus was greatly facilitated by the work of many famous writers, for example, Victor Hugo described in his novel “Toilers of the Sea” octopus as “the absolute embodiment of evil.” In reality, octopuses, of which there are more than 200 species in nature, are completely harmless creatures, and it is rather they who need to be afraid of us humans, and not vice versa.
The closest relatives of octopuses are squid and cuttlefish; they themselves belong to the genus of cephalopods, the family of octopuses proper.
Octopus: description, structure, characteristics. What does an octopus look like?
The appearance of the octopus is confusing; it is immediately unclear where its head is, where its mouth is, where its eyes and limbs are. But then everything becomes clear - the sac-like body of the octopus is called the mantle, which is fused with a large head, and there are eyes on its upper surface. The eyes of an octopus have a convex shape.
The octopus's mouth is tiny and surrounded by chitinous jaws called the beak. The latter is necessary for the octopus to grind food, since they cannot swallow prey whole. He also has a special grater in his throat, which grinds pieces of food into pulp. Around the mouth there are tentacles, which are the true calling card of the octopus. The octopus's tentacles are long, muscular, and their lower surface is studded with suckers of varying sizes, which are responsible for taste (yes, the octopus's suckers contain its taste buds). How many tentacles does an octopus have? There are always eight of them, in fact, the name of this animal comes from this number, since the word “octopus” means “eight legs” (well, that is, tentacles).
Also, twenty species of octopuses have special fins that serve as a kind of rudders when they move.
Interesting fact: octopuses are the most intelligent among mollusks; the octopus' brain is surrounded by special cartilage, strikingly similar to the skull of vertebrates.
All the senses of octopuses are well developed, especially vision; the eyes of octopuses are very similar in structure to human eyes. Each of the eyes can see separately, but if the octopus needs to look at some object more closely, the eyes easily come together and focus on a given object, in other words, octopuses have the rudiments of binocular vision. Octopuses are also capable of detecting infrasound.
The structure of the internal organs of an octopus is unusually complex. For example, their circulatory system is closed, and the arterial vessels are almost connected to the venous ones. The octopus also has three hearts! One of them is the main one, and two small gills, whose task is to push blood to the main heart, otherwise it directs the flow of blood throughout the body. Speaking of octopus blood, it's blue! Yes, all octopuses are real aristocrats! But seriously, the color of octopus blood is due to the presence of a special pigment in it - geocyamine, which in them plays the same role as hemoglobin in us.
Another interesting organ that the octopus has is the siphon. The siphon leads into the mantle cavity, where the octopus draws water and then, abruptly releasing it, creates a real jet that pushes its body forward. True, the octopus’s jet device is not as perfect as that of its relative the squid (which became the prototype for the creation of a rocket), but it is also excellent.
The sizes of octopuses vary between species, the largest of which is 3 meters long and weighs about 50 kg. Most species of medium-sized octopuses range from 0.2 to 1 meter in length.
As for the color of octopuses, they usually have red, brown, or yellow colors, but they can also easily change their color like this. Their mechanism for changing color is the same as that of reptiles - special chromatophore cells located on the skin can stretch and contract in a matter of seconds, simultaneously changing color, and making the octopus invisible to potential predators, or expressing its emotions (for example, angry the octopus turns red, even black).
Where does the octopus live?
The habitat of octopuses is almost all seas and oceans, with the exception of northern waters, although they sometimes penetrate there. But most often, octopuses live in warm seas, both in shallow water and at very great depths - some deep-sea octopuses can penetrate to depths of up to 5000 m. Many octopuses like to settle in coral reefs.
What do octopuses eat?
Octopuses, however, like other cephalopods, are predatory creatures; their diet consists of a variety of small fish, as well as crabs and lobsters. They first capture their prey with their tentacles and kill them with poison, then they begin to absorb them, since they cannot swallow whole pieces, they first grind the food with their beak.
Octopus lifestyle
Octopuses usually lead a sedentary, sedentary lifestyle; most of the time they hide among reefs and sea rocks, emerging from their hiding places only to hunt. Octopuses usually live alone and are very attached to their area.
How long do octopuses live?
The lifespan of an octopus is on average 2-4 years.
Octopus enemies
One of the most dangerous enemies of the octopus in recent times is humans, which is greatly facilitated by cooking, because many delicious and delicious dishes can be prepared from octopus. But besides this, the octopus also has other natural enemies, various sea predators: sharks, sea lions, fur seals, and killer whales are also not averse to feasting on the octopus.
Is octopus dangerous for humans?
Only on the pages of books or in various science fiction films, octopuses are incredibly dangerous creatures, capable of not only easily killing people, but also destroying entire ships. In reality, they are quite harmless, even cowardly; at the slightest sign of danger, the octopus prefers to retreat by flight, no matter what happens. Although they usually swim slowly, when in danger they turn on their jet engine, allowing the octopus to accelerate to a speed of 15 km per hour. They also actively use their ability of mimicry, merging with the surrounding space.
Only the largest species of octopus can pose some danger to scuba divers, and then only during the breeding season. In this case, of course, the octopus itself will never be the first to attack a person, but in defense, it can sting him with its poison, which, although not fatal, will, of course, cause some unpleasant feelings (swelling, dizziness). The exception is the blue-ringed octopus, which lives off the coast of Australia, whose nerve venom is still fatal to humans, but since this octopus leads a secretive lifestyle, accidents with it are very rare.
Types of octopuses, photos and names
Of course, we will not describe all 200 species of octopuses; we will focus only on the most interesting of them.
As you probably guessed from the name, this is the largest octopus in the world. It can reach up to 3 meters in length and up to 50 kg in weight, but these are the largest individuals of this species; on average, a giant octopus is 30 kg and 2-2.5 meters in length. Inhabits the Pacific Ocean from Kamchatka and Japan to the west coast of the USA.
The most widespread and well-studied species of octopus, living in the Mediterranean Sea and the Atlantic Ocean, from England to the coast of Senegal. It is relatively small, its body length is 25 cm, and together with the tentacles it is 90 cm. The body weight is on average 10 cm. It is very popular in the cuisine of the Mediterranean peoples.
And this beautiful species of octopus, which lives off the coast of Australia, is also the most dangerous among them, since it is its poison that can cause cardiac arrest in humans. Another characteristic feature of this octopus is the presence of characteristic blue and black rings on its yellow skin. A person can only be attacked while defending himself, so to avoid trouble, you just need to stay away from him. It is also the smallest octopus, its body length is 4-5 cm, its tentacles are 10 cm, and its weight is 100 grams.
Octopus breeding
Now let's look at how octopuses reproduce; this process is very interesting and unusual. Firstly, they reproduce only once in their lives and this action has dramatic consequences for them. Before the mating season, one of the tentacles of a male octopus turns into a kind of sexual organ - a hectocotylus. With its help, the male transfers his sperm into the mantle cavity of the female octopus. After this act, the males, alas, die. Females with male reproductive cells continue to lead a normal life for several months, and only then lay eggs. There are a huge number of them in the clutch, up to 200 thousand pieces.
Then it lasts for several months until the young octopuses hatch, during which time the female becomes an exemplary mother, literally blowing away specks of dust from her future offspring. In the end, the female, exhausted from hunger, also dies. Young octopuses hatch from eggs completely ready for independent life.
- More recently, many people have heard of the famous octopus Paul, the octopus oracle, the octopus predictor, who with amazing accuracy predicted the results of football matches at the European Championships in Germany in 2008. In the aquarium where this octopus lived, two feeders with flags of opposing teams were placed, and then the team from whose feeder Paul the octopus began his meal won the football match.
- Octopuses have played a significant role in people’s erotic fantasies for quite some time; back in 1814, a certain Japanese artist Katsushika Hokusai published an erotic engraving, “The Dream of a Fisherman’s Wife,” which depicts a naked woman in the company of two octopuses.
- It is quite possible that, as a result of evolution, over millions of years, octopuses will develop into intelligent creatures similar to humans.
Life of an Octopus, video
And finally, an interesting documentary about octopuses from National Geographic.
And therefore, a discovery that is applicable to one of its forms can be applied to all others. Thanks to which, by the way, the functions of many were studied and methods of treating dangerous diseases were developed.
Examples of analogous and homologous organs
It is impossible, however, based on the relatedness of all living things on earth, to mix homologous and similar organs. The former have the same structure and develop from the same embryonic rudiments, confirming the unity of origin (for example, the five-fingered limb of different animal species). But similar organs, which often perform the same function in different animals, have different rudiments.
A common example of such cases is the wing. It performs an identical function in both insects and birds. But in insects these are chitinous protrusions on the surface of the back, and in birds they are forelimbs that have changed during the process of evolution. The same parallel can be drawn between the gills of fish and fish.
The eyes of humans and octopuses can also be defined as similar organs. Despite their external similarity, they are absolutely
different in structure. The lens of the human eye is fixed, and the eye itself is an outgrowth of the rudiment of the brain. While in an octopus, the organs of vision are formations from the body cover, in which the lens of the lens approaches or moves away from the retina, aiming at the object of the animal’s attention in order to establish the correct focus.
Examples of analogy can be considered even among pigments such as hemoglobin and hemocyanin. They carry oxygen in the same way, but their molecular structure is very different.
Rudiments
In their own way they confirm the theory
The latter usually include those organs that do not perform their original function, having lost it in the process of evolution. But all rudiments cannot be considered absolutely useless. They simply often perform less important actions.
So, for example, the wings of an ostrich can be defined as because they do not cope with the main task of a bird’s wing, but are used by it to attract females and to maintain balance while running. Thus, the complexity of the structure of this organ is inadequate to the simplicity of the task it performs. This is a sign of a rudiment.
The rudiments include the eyes of a mole and a mole rat, which either do not see anything at all, or only distinguish between darkness and light.
In humans, this characteristic is found in the caudal vertebrae, muscles that
helped our ancestors raise their hair on end and muscles to move their ears. Everyone knows another human rudiment - an appendix.
Atavisms
When an individual develops characteristics characteristic of its distant ancestors, this phenomenon is called atavism. For example, the appearance in some people of continuous hair on the body or an additional pair of mammary glands, a caudal process in humans or rear fins in a dolphin.
The appearance of atavisms can be explained by the presence of genes responsible for this trait in DNA. But they have not functioned for a long time, since their action is suppressed by other genes.
Homologous and similar organs, rudiments and atavisms - all this is an undoubted confirmation of the unity of the origin of life of the creatures inhabiting the Earth.
To the question What is unusual about the eyes of an octopus? given by the author Irina Petrotsi the best answer is If, writes one scientist, you ask a zoologist to indicate the most striking feature in the development of the animal world, he would name not the human eye (of course, this is an amazing organ) and not the octopus eye, but would draw attention to the fact that both of these eyes, the eye a person and the eye of an octopus are very similar." They are similar not only in their structure, but often even in their expression - a strange fact that has always amazed naturalists.
The eye of an octopus is not much different from the eye of a mammal or even a human. But there are some differences: for example, the cornea of most cephalopods is not solid, but is pierced in front by a small (cuttlefish) or rather wide (squid) hole. The lens is not elliptical, but round, divided in half by a thin epithelial plate. “In addition,” writes the famous Soviet researcher V.A. Dogel, “in the eye of Cephalopoda there are adaptations to vision in both stronger and weaker lighting. The cells of the retina contain brown granular pigment. The latter is distributed throughout the entire cell and, thus, partly protects the cell from too strong illumination, but at night all the pigment is concentrated only at the base of the cell, the sensitivity of which increases as a result.” Accommodation (setting vision at different distances, focusing) in humans is achieved by changing the curvature of the lens, and in cephalopods - by removing or bringing it closer to the retina, just as the lens moves in a camera.
None of the inhabitants of the sea have such keen eyes as the octopus and its relatives. Only the eyes of an owl, a cat, and a human can compete with them.
On one square millimeter of the retina of an octopus there are about 64 thousand visual elements that perceive light, in a cuttlefish there are even more - 150 thousand, in a squid - 162 thousand, in a carp - 50 thousand, in a cat - 397 thousand, in a person - 400 thousand, and the owl even has 680 thousand.
And the size of the eyes of cephalopods is record-breaking. The cuttlefish's eye is only ten times smaller than itself, and the giant octopus has eyes the size of a small wheel: 40 cm in diameter! A thirty-meter blue whale's eye does not exceed 10-12 cm in length (200-300 times smaller than the whale itself).
Answer from Signal[guru]
The eyes are large, with a lens similar to that of a human. The pupil is rectangular
The eyes of an octopus are very expressive. Apparently, this is why they are often compared to human ones. The cells of the octopus's retina include a brown pigment, which neutralizes too bright light during the day and increases the sensitivity of the eye at night. Focusing the gaze on objects located at different distances is accomplished by moving the lens closer or further away from the retina. During deep sleep, the octopus does not close its eyes, but only strongly constricts its pupils. His breathing slows down, he presses all tentacles, except the two lower ones, to his body. The two lower arms outstretched to the sides perform a guard function. Touching them, as well as the slightest vibration of the water, acts on a sleeping octopus like an alarm clock.
Since the appearance on the screens of Proulx’s quarrelsome “colleague,” a cephalopod professor from the planet Ocean, who visited Earth in the film “Through Thorns to the Stars,” schoolchildren are also aware of the mental abilities of octopuses. But this familiar idea does not allow us to properly experience the truly amazing capabilities of these cephalopods. Spanish biologist Antonio Barrow, who has been studying them for many years, claims: sometimes, while people are not looking, octopuses leave their aquarium, get to the neighboring one, where fish for food is stored, and, after having a snack, quietly return back. They are the only invertebrates whose management in Europe is controlled by Directive 2010/63/EU, the protagonists of which are our native mammals.
Roman Fishman
Octopuses build shelters for their offspring from scrap materials and memorize complex “maps” of the surrounding landscape. They steal fishermen's catch and easily get to the delicacy locked under a screw cap or even in a child-resistant bottle - a task that is not always feasible for an adult. In the spring of 2016, one of them escaped from an aquarium in New Zealand, getting out into the sea through a sewer. Octopuses distinguish between people and can seriously dislike them. They solve non-standard problems that neither the animal itself nor its ancestors have encountered, like recognized clever people like dogs, ravens or people. But if sometime in the past - or somewhere on another ocean planet - they managed to develop a full-fledged mind, then it would be a mind completely different from that of a human or even a dog.
Alien nervous
The predecessors of cephalopods abandoned the shell about 500 million years ago, preferring freedom and movement. The ancestors of octopuses, of which there are about 200 species today, became active predators and potentially available prey and, apparently, could not help but develop a complex nervous system unique to invertebrates. It contains about 500 million cells - more than a rat's and almost the same as a cat's brain.
We take our centralized, hierarchical nervous system for granted. However, animals demonstrate that everything can be arranged completely differently.
But the nervous system of octopuses is not reduced to the brain in its usual role as a centralized organ of analysis and control. Their skeletal bodies can bend anywhere and in any direction. Such flexibility requires equally complex and flexible control, and the solution to this problem in cephalopods is delegated to “in situ”—large clusters of neurons located in the body. The central brain accounts for only about 10% of the cells, and a pair of large optic lobes accounts for another 30%. The rest are located in the ganglia of the limbs and act more or less independently - it is not without reason that the severed tentacle continues to contract and move for a long time.
When a person opens a jar, his brain, focusing on signals from his senses, issues precise signals to the muscles of his hands. Apparently, it is enough for an octopus to trigger the desired behavioral reaction; How exactly to implement it and get it out of a closed jar of crab, the tentacles “decide” themselves. This distributed nervous system makes octopuses something like adherents of the Order of the Faceless Ones from Game of Thrones, allowing them to have virtually no appearance of their own, changing color, shape and even surface texture. “Thinking legs” independently cope with complex manipulations and transformations, receiving only general instructions from the center.
Marine technology
Why haven't octopuses become as dominant in the oceans as humans have been on land? The reason does not lie in a lack of intelligence. The blame for this is rather due to some very inconvenient features of their anatomy. For example, the blood of cephalopods uses hemocyanin, which does not contain iron, like our hemoglobin, but copper. It is less efficient in delivering oxygen, so octopuses simply do not have enough “breathing” for many complex tasks. Octopuses are not very social, do not pass on experience from generation to generation and live no more than a few years - each of them has to start learning about the world from scratch. If not for these factors, cephalopods and their relatives could have created impressive examples of intelligence, and one day the two-legged “kings of the land” would have entered into a great war with the civilization of the eight-legged “kings of the sea.”
The world's oceans provide enough funds for the development of technology. Underwater volcanoes, tides, sun, waves and wind can serve as sources of energy. Oil and gas resources, deposits of nickel, manganese and cobalt are hidden at the bottom. Even more metals are extracted from seawater - to obtain a kilogram of iron, you only need to filter 50 thousand m3. The diversity of marine life will provide a good basis for the development of biotechnologies, including bioluminescent lighting based on deep-sea organisms and construction using coral polyps. Electrolysis of water will make it possible to obtain oxygen and hydrogen - fuel components that make it possible to begin jet propulsion, first in water, and then in the atmosphere and near space. However, our planet does not provide many opportunities for such a scenario. Water covers more than 70% of its surface, but by mass it accounts for only about 0.05%. Meanwhile, distant exoplanets consist of 10 percent or more water. For example, six planets of the Kepler-11 system are completely covered with oceans to a depth of hundreds of kilometers. The age of this star is estimated at 8.5 billion years, about twice as old as ours. So why shouldn’t intelligent inhabitants similar to our cephalopods appear in the deep ocean worlds under this ancient star? And if so, then why not one day a team of scientists from Kepler-11, led by the new Professor Proulx, try to make contact with us?.. If you believe the film, there is not long to wait, only until the 23rd century.
10 Amazing Facts About Octopuses
1. The retina of their eyes contains only one type of pigment, allowing them to see only in black and white. Perhaps color vision in octopuses is given by the special anatomy of the pupils.
2. They are the only invertebrates whose management in Europe is controlled by Directive 2010/63/EU, otherwise dedicated to smart mammals.
3. On average, there are 240 suckers per tentacle, but in total there are more than 1900 of them.
4. The ink of some cephalopods produces a long-lasting brown color and has been used by artists since ancient times. The name "sepia" comes from Sepiida, meaning "cuttlefish".
5. They have three hearts, two of which are occupied only by tentacles, and one washes the internal organs with blood. When swimming, this heart stops working, so they usually prefer to crawl.
6. Aristotle considered them narrow-minded: “Octopuses are stupid creatures and they themselves swim up to the hand if you put it in the water,” he wrote in “History of Animals” 350 BC. e.
7. The complete genome of the octopus O. bimaculoides has been deciphered. Its length is 2.7 billion base pairs, almost the same as that of a human and many times longer than that of any other invertebrate.
8. The ink they throw out in case of danger not only masks the octopus, but is also toxic. An octopus that does not leave its own ink cloud in time may die.
9. The female lays up to hundreds of thousands of eggs and actively “ventilates” them for months, never leaving the nest for a minute. This activity completely exhausts and ultimately kills her.
10. Males die even earlier, after fertilization. Apparently, no octopus has ever met its parents.
Zhanna Reznikova, Doctor of Biology. Sciences, Professor of the Department of General Biology of NSU
“On par with the most “advanced” species of mammals and birds, cephalopods are capable of one of the highest forms of learning - imitation. Back in the 1990s, it was shown that an octopus, watching its fellow octopus in a nearby aquarium learn to choose an object of a certain color, subsequently, when solving this task on its own, chose an object of the same color as the “teacher.” This octopus experiment has been criticized as not being rigorous enough, but scientists have recently convincingly demonstrated imitation learning in another cephalopod, the cuttlefish.”
Sense organs and habits of cephalopods
(based on articles from Sakhalin)
The human eye and the octopus's eye are surprisingly similar not only in their structure, but often even in their expression - a strange fact that has always amazed naturalists.
The cornea of an octopus's eye is not solid, but has a wide hole in the center. Accommodation (setting vision at different distances - focusing) in humans is achieved by changing the curvature of the lens, and in an octopus - by removing or bringing it closer to the retina, similar to the movement of the lens in a camera. The octopus's eyelids are closed by the ring muscles and, closing the eye, they draw it in like a curtain on a ring cage.
None of the inhabitants of the sea have such keen eyes as the octopus and its relatives. Only the eyes of an owl, a cat, and a human can compete with them.
On one square millimeter of the retina of an octopus there are about 64 thousand visual elements that perceive light, in a cuttlefish there are even more - 105, in a squid - 162, in a spider there are only 16, in a carp - 50, in a cat - 397, in a person - 400 , and the owl even has 680 thousand.
And the size of the eyes of cephalopods is a record one. The cuttlefish's eye is only ten times smaller than itself, and the giant octopus has eyes the size of a small wheel. Forty centimeters in diameter! Even a thirty-meter blue whale's eye does not exceed 10-12 centimeters in length (200-300 times smaller than the whale itself).
But the most unusual eyes are those of deep-sea squids: in some they stick out upward like telescopes, in others on thin stalks they are carried far to the sides, and there are squids that (an unprecedented thing!) have asymmetrical eyes: the left one is 4 times more to the right. How these animals swim: after all, their heads are unbalanced... They probably have to make a lot of effort to swim forward and not roll over.
Professor Gilbert Boss from the Oceanographic Institute in Miami (USA) thinks that the large eye is adapted to the depths; it collects the crumbs of light scattered there with its powerful optical system. With its small eye, the squid surveys its surroundings, floating to the surface. It is quite possible.
Squids also have very special eyes, not found in anyone else in nature - thermoscopic. They “see”... warmth. On the fins of the Mastigotheuthis squid there are about 30 miniature “thermal locators”, apparently capable of perceiving heat rays. They are scattered as dark dots in the skin. Under a microscope, it can be seen that the organ consists of a spherical capsule filled with a transparent substance. On top of the capsule is covered with a thick layer of red cells - this is a light filter, it blocks all rays except infrared ones.
Apparently, in the thermoscopic eyes of squids, photochemical processes of the same type occur as on the retina of an ordinary eye or on a photographic plate. The energy absorbed by the organ leads to the recombination of light-sensitive (in squids, heat-sensitive) molecules, which act on the nerve, causing the brain to imagine the observed object.
American rattlesnakes and copperheads, which are also found in Siberia, also have unique thermolocators on their heads, but they are designed differently: on the principle of a thermoelement.
Snakes, using thermolocators, search in the dark for warm-blooded rodents and birds, which, like any heated body, emit infrared rays.
Why do squids need thermoscopic eyes? After all, at the depths where they live, there are no warm-blooded animals...
Isn't it? And the sperm whale? This voracious whale dives very deep and hunts squid in the abyss of the sea. Eats several tons of them a day. I examined the stomach contents of several hundred sperm whales caught by our whaling fleets, and was convinced that the majority of the menu of old Moby Dick was made up of deep-sea squid. Hundreds of thousands of sperm whales devour hundreds of millions of squid every day, mostly deep-sea ones.
That is why, notes I. Akimushkin, the inhabitants of the cold abyss have developed eyes that “see” warmth. There are no local warm-blooded animals there, it’s true, but from above, from the shining azure of the sea, huge voracious animals invade the kingdom of eternal darkness. The squids are alerted to their approach by thermolocators.
Octopus mother hen
One day, writes Frank Lane, in a marine aquarium in California, an octopus named Mephista laid eggs - small gelatinous lumps. Mephista wove her eight arms like a basket. It was a nest. For two months, while the octopus was hatching eggs in it, she did not eat anything.
If one of the servants dared to throw a piece of meat right to her head, Mephista would flush brick-red in anger, free her hand from the makeshift basket and throw away her previously favorite food - after all, this “garbage” could get on her precious eggs!
When Mephista was not disturbed, she gently fingered the eggs, rocked them, as if cradling them, and poured water from the funnel.
But then little octopuses (each the size of a flea) hatched from the eggs and, sparkling with new outfits, set off in search of adventure in the watery jungle. The brood left Mephista - her duty was completed, but she still needed to cradle and protect someone. Alas! She was left with only empty shells.
Day after day, still refusing food, Mephista now senselessly protected what should have been thrown away long ago. One morning she was found at her previous post, but Mephista was not vigilant. Pieces of food and scraps of algae surrounded the shells to which she had given life.
Another octopus, from the Brighton Aquarium, was not so reckless. She laid her eggs (shown) in a hole in the artificial rock (close to the glass so the animals were easy to observe). She surrounded her nest with a rampart, dragging in several dozen live oysters and piling them on top of each other. She settled herself behind this barricade, only her bulging eyes looked out from the fortress, vigilantly examining the surroundings. The octopus extended its two longest tentacles beyond the fortification; their ends constantly wriggled, as if searching for possible enemies.
The female two-spotted octopus, Mephista’s compatriot, when the water was drained from the pool where she was hatching eggs for regular cleaning, refused to leave her post. The water level inexorably dropped, the male octopus sank along with it, retreating step by step following its native element.
But the mother octopus remained on land for 20 minutes and, while the aquarium was being cleaned, covered the eggs with her body. And long after the water released into the pool covered her again, the octopus could not catch her breath.
Aristotle also noticed that female octopuses, while hatching eggs, starve for many years.
weeks Only rare octopuses decide to take a little food near the protected eggs. Usually they do not eat anything for a month, or two, or even four months, while incubation lasts.
This asceticism is caused by the desire to protect eggs from contamination. Even adult octopods cannot tolerate stale water. Therefore, the incubating octopuses constantly water the eggs with a stream from the funnel - they wash them. Everything that can rot is expelled by the octopus from the nest. The water must be clean: For this, octopuses starve: they are afraid to drop even crumbs from their table onto the precious eggs in which the future of their species lies.
Fanatical devotion to their maternal duties, dictated by a harsh instinct, often causes irreparable harm to the health of octopuses. Most of them die, giving life to a new generation.
House in a bottle
The French scuba divers Cousteau and Dumas, known to our readers from the book “In a Silent World,” once found a sunken ancient Greek ship near Marseille. Its holds were filled with amphorae - huge jugs in which the Greeks stored wine. Almost every amphora contained an octopus. The death of the trireme, says Cousteau, gave a thousand ready-made apartments to the octopuses, which apparently are experiencing an acute shortage of living space. "Certainly they inhabited the ship for two millennia." The entrances to the amphorae were barricaded with fragments of dishes, shells, pebbles, and scraps of algae, which “for centuries were collected by octopuses faithful to their habits.”
The passion of octopuses for dishes and their desire to climb into various hollow objects has been known for a long time. One hundred and fifty years ago, the French zoologist Orbigny wrote about this. But even earlier, and with great benefit for themselves, fishermen from the shores of the Mediterranean Sea used this passion for octopuses. I’ll tell you how we used it a little later.
Female octopuses willingly climb into the large shells of sea snails - they look there for a safe shelter for their offspring, which, as we already know, they treat with touching devotion. One octopus was recovered along with its eggs from a broken bottle. Another was found inside a human skull caught in the Mediterranean Sea near Posilippo. The octopus really liked this gloomy dwelling, and he never wanted to leave it. There is a story about a diver who was scared to death by an octopus that got into his trousers, which were lying in the cabin of a sunken ship. The diver extended his hand to them, and the pants suddenly jumped up and took off running.
One day, an octopus was found inside a two-gallon bottle recovered from the bottom of the English Channel. The neck of the bottle was no more than five centimeters in diameter. However, the octopus managed to squeeze its “rubber” body into it, the width of which exceeded thirty centimeters. A gasoline canister from a crashed plane also gave shelter to a resourceful octopus with her numerous eggs.
Small octopuses climb inside oyster shells after eating their rightful host. There they attach themselves to both leaves at once and in this way keep them tightly closed. Zoologist M. Wells once picked up twenty oysters filled with octopus eggs on the sandbanks of Florida. In fifteen shells, octopuses who did not want to leave their brood were hiding, and one mother sat nearby in thought, solving the painful problem - to run or stay?
The question of how octopuses open tightly closed oyster shells has long been debated in teutological science. Two thousand years ago, the Roman naturalist Caius Pliny the Elder believed that octopuses used cunning to take over fortresses in which tasty mollusks were hidden. Stocking up on patience and stones, they seem to be on duty at a closed sink for a long time. As soon as it opens, the octopus immediately throws a stone inside. The valves can no longer close, and the octopus, as calmly as on a platter, eats the oyster, and then settles in its house.
This story is still well known to many fishermen from the shores of the Mediterranean Sea. Obviously, they did not learn about the ingenious tricks of octopuses from ancient manuscripts. However, many scientists treat Pliny's story with great skepticism.
We did the following experiment: in an aquarium we gave tightly closed mollusk shells to hungry octopuses, and gave them stones. They began to watch. The wasp lampreys behaved as if they had no idea about the method recommended by Pliny the Elder.
However, this failure did not stop the most ardent enthusiasts. After all, it is well known that many animals behave differently in captivity than in nature. And so, writes Frank Lane, two researchers managed to confirm with their observations the old legend about octopuses throwing stones at mollusk shells.
On the Tuamotu Islands, traveler Wilmon Monard, armed with a glass-bottomed box through which oyster and pearl fishermen look for prey at the bottom, saw many times how octopuses attacked oysters, throwing pieces of coral into their shells.
Jet engine
We move on to a description of the most interesting organ of cephalopods - the jet engine. Notice how simply, with what minimal use of material, nature solved a complex problem.
Below, at the “neck” of the squid (let’s take this mollusk as an example), a narrow gap is noticeable - the mantle opening. Some kind of tube sticks out from it, like a fluff from an embrasure. This is a funnel, or siphon, the “nozzle” of a jet engine.
Both the gap and the funnel lead to a vast cavity in the squid’s “stomach”: the mantle cavity is the “combustion chamber” of a living rocket. Sucking water into it through a wide mantle slit, the mollusk then forcefully pushes it out through the funnel. To prevent water from flowing back through the gap, the squid closes it tightly using special “fastener buttons” when the “combustion chamber” is filled with sea water. Along the edge of the mantle opening there are cartilaginous mushroom-shaped tubercles. On the opposite side of the slot they correspond to indentations. The tubercles fit into the recesses and firmly lock all exits from the chamber, except one - through the funnel.
When the mollusk contracts its abdominal muscles, a strong stream of water shoots out from the siphon. The recoil pushes the squid in the opposite direction.
The funnel is directed towards the ends of the tentacles, so the cephalopod swims tail first. That’s why the cuttlefish in Korney Chukovsky’s “Cockroach” “rolls and backs away” - a circumstance that I remember very embarrassed me in childhood.
Jet shocks and the absorption of water into the mantle cavity follow one after another with elusive speed, and the squid rushes like a rocket in the blue of the ocean. If the shocks were separated from each other by significant periods of time, as in the scallop or eshna, then the animal would not receive any special benefits from such movement. To accelerate the rate of jet “explosions” and bring it to breakneck speed, it is obviously necessary to have increased conductivity of the nerves that excite the contraction of the muscles that serve the jet engine.
The conductivity of a nerve, other things being equal, is higher, the larger its diameter. Indeed, in squids we find the largest nerve fibers in the animal kingdom. Their diameter reaches a whole millimeter - 50 times larger than that of most mammals - and they excite at a speed of 120 meters per second.
The three-meter-long squid Dosidicus (which lives off the coast of Chile) has a fantastically large nerve thickness - 18 millimeters. Nerves are thick, like ropes. Brain signals - the exciters of contractions - rush along the squid's nervous "freeway" at the speed of a racing car - 90 kilometers per hour!
Squids, like rockets, quickly rush through the ocean waters
When these supergiant nerves were discovered at the beginning of our century, physiologists immediately became interested in them. They finally found an experimental animal in which needle electrodes could be inserted into living nerves. The study of the vital activity of nerves immediately advanced
A frightened squid jerks back with the help of a “jet engine”
forward. “And who knows,” writes British nature writer Frank Lane, “maybe “there are now people who owe the squid the fact that their nervous system is in a normal state.”
How do octopuses travel on land?
The most incredible things happen to these animals.
American zoologist Paul Batsch says: once fishermen caught an octopus. They wanted to boil it and eat it. The octopus was small - about half a meter long. Then they realized that he had pretended to be dead. They put him in a cauldron and lit a fire under the cauldron.
The cook left for a while. He returned and lifted the lid of the cauldron to try to see what kind of stew came out of the octopus. The cauldron was empty, that is, there was water in it, but there was no octopus in it. They found him on the roof of the house.
When the cauldron became hot, the octopus lifted the lid of his prison. I climbed up the chimney to the roof. He climbed out through the pipe like a real pipe cleaner, and stopped in thought only in front of a new
an obstacle - an element of air that suddenly opened up in front of him.
When octopuses travel on land, they take a piece of the sea with them. Water is stored in the mantle cavity, tightly closing all entrances and exits from it. The supply of oxygen dissolved in this water is enough for a musk octopus, for example, to breathe on land for four hours. Frank Lane says that ordinary wasp lampreys, thrown to the bottom of a boat - they were then going to cut them up for bait - lived without water for two days!
The opinion of researchers about the speed at which octopuses move on land cannot be called unanimous. According to some observations, the octopus crawls along the ground, covering about eight yards (430 meters per hour) in a minute. Others claim that the octopus runs even faster - a person walking at a fast pace seems to have difficulty catching up with it. My own experience tells me that the octopus is hardly able to move on land at all. However, perhaps, as the Soviet researcher of cephalopods N. Kondakov believes, different types of octopuses have different abilities to walk on the ground. The octopuses that will now be discussed obviously belonged to other species, more mobile on land, than those that I had to observe.
Thacker Abott, an American zoologist, in a book about mollusks, described the adventures of an octopus that escaped from an aquarium in Bermuda. The octopus himself lifted the lid of the pool in which he was held captive, went down to the floor, went out onto the veranda and headed towards the sea. He hobbled along the ground for about 30 meters and was attacked by hordes of ants.
An octopus brought to land always unmistakably knows which way the sea is. He crawls towards him with such straightforwardness that, as some observers claim, he would rather walk through a burning fire that he met on the way than deviate two steps from his chosen course. Which sense shows him the right path: smell or the perception of the infra- and ultrasonic sounds of the sea unknown to us? It's not clear yet. In recent years, science has made significant progress in understanding the methods of orientation of animals. Perhaps the mysterious ability of octopuses to accurately find their home will soon be unraveled.
Fishermen in the English Channel caught a small octopus along with the fish and left it on the deck. Two hours later they remembered it, started looking for it and found it in... a kettle that was standing in the wheelhouse. Octopus climbed the ladder onto the captain's bridge and, of course, could not overcome his natural attraction to dishes.
“Guy Gilpatrick,” write Cousteau and Dumas, “talks about how an octopus was released into freedom in a library. He began running up and down the shelves, throwing books onto the floor; it was obviously a belated revenge on the writers!”
Gilpatrick himself describes this adventure somewhat differently. He brought a bucket of octopus to the library to show his friends. While I was waiting for them, I got carried away with reading. Suddenly he hears a noise: the octopus, of course, got out of the bucket and waddled along the floor - a kind of lame gnome! - and began climbing the bookshelves. With difficulty I reached the third shelf and stopped, exhausted, in front of a thick volume. Apparently, the eight-legged climber had strained himself - he turned pale and suddenly collapsed dead on the floor.
Perhaps there was another reason for his tragic death. Gilpatrick claims that the book that made such a depressing impression on the octopus was his, Gilpatrick's, own composition...
Octopus taste
Even blinded octopuses see the light. Or rather, they feel it over the entire surface of the body. They have a very sensitive skin: tactile, photosensitive, olfactory and taste cells are scattered in the skin.
The octopuses recognized the taste of the food offered by the experimenters not only with their tongue. And even mainly not with the tongue, but with the hands. The entire inner surface of the tentacles (but not the outer) and each sucker are involved in tasting food. To find out whether the offered dish matches its taste, the octopus tastes it with the tips of its tentacles. If it is an edible piece, he pulls it into his mouth, regardless of the opinion of other senses, such as touch. They gave the octopuses porous stones soaked in meat extract. By touch one could conclude that this object was inedible, but the tentacle-tasters, seduced by the juice of the hot something, did not pay attention to the protests of the tactile nerves. The octopus brought the stone to its mouth, tried to chew it, and only then threw it away. On the contrary, the octopus disdainfully rejected pieces of meat that were quite edible, but devoid of juices, lightly touching them with the tip of one of its eight hands.
The octopus's sense of taste is so subtle that it apparently recognizes its enemies by taste. McGinity, an American oceanographer, released a drop of water from a pipette near an octopus; the experimenter had sucked up the water in another aquarium near a moray eel, the octopus’s worst enemy. The octopus acted according to the simulated situation: it got scared, turned purple and took off running.
However, it is still a question of how he recognized the enemy - taste or smell. Difference
there is little difference between these feelings, and octopuses seem to have none at all. We already know that the taste organs, capable of distinguishing sweet from sour, bitter from salty, are located in the octopus, in addition to the tongue and lips, also on the inside of the tentacles. But with its tentacles, the octopus also perfectly recognizes odors: the smell of musk and other odorous substances. What sense notifies, for example, a blind octopus of where a dead fish lies? He unmistakably finds her even at a distance of one and a half meters. Taste? Smell?
A well-fed octopus usually does not show interest in food - it is not a glutton, but a tentacle cut off from the same octopus, devoid of control: the brain, stubbornly crawls for a tasty morsel, apparently in octopuses (and, of course, in squids and cuttlefish) taste and smell are inseparable.
It remains to mention one more sense - hearing. Do octopuses hear or are they deaf to everything?
They probably can hear a little if you shout in their ear. However, this is not easy to do: it is not easy to find an octopus “ear” outside. There are no external signs that would indicate its existence. But if we cut into the cartilaginous skull of an octopus, inside we will find two bubbles with lime crystals enclosed in them. These are statocysts - the organs of hearing and balance. The impacts of sound waves vibrate the limestone pebbles, they touch the sensitive walls of the bubble, and the animal perceives the sound, obviously, as an unclear hum.
The lime crystals also tell the octopus about the position of its body in space. Octopus-legs with statocysts removed lose their orientation: they swim with their backs down, which normal animals never do, otherwise they will suddenly start spinning like a top or confuse the top and bottom of the pool.
Why does a hare have thin skin?
Try to grab the lizard by the tail - the tail will remain in your hands, and the lizard will duck into a crack in an old stump. The lizard's tail will soon grow back.
Grab a grasshopper by the stilt leg - it will tear it off and gallop away on one leg.
The sea cucumber, fleeing, will leave in your hands the half that you managed to grab. And other sea cucumbers throw out their intestines through their mouth, as if from a catapult - they say, eat, just leave me alone!
The hare does not have a long tail, like a lizard, which he could part with if necessary. He cannot even sacrifice his leg, like a grasshopper. After all, fast legs are his only salvation.
It’s another thing to leave a tuft of fur in the mouth of a predator... That’s why a hare’s skin is thin. If the fox grabs the hare by the side, he will rush and run away. If his skin weren’t as thin as parchment, it wouldn’t tear easily, and he wouldn’t get off so cheaply with a scythe.
At the site of the torn skin, not a speck of blood will appear on the hare, and the wound will soon be covered with new hair.
Other animals easily part with their fur coats. The garden dormouse, a small, squirrel-like animal, “pops out” from its tail if a predator grabs it. Fluffy
the skin easily bursts, and the dormouse runs away with a bare tail, but alive.
The gopher and chipmunk, they say, do the same.
And a small brown lizard that lives on the Palau Islands in the Pacific Ocean instantly jumps out of its skin if you cover it with your hand. A thin skin will remain in your hand, and a naked lizard will scurry under a stone.
Scientists call such merciless but life-saving self-mutilation autotomy - self-cutting. Many animals resort to this operation to avoid imminent death.
Autotomy - the oldest means of life insurance - is also in the arsenal of protective devices of the octopus. Eight long arms, which explore every inch of unfamiliar space, when the octopus goes out to prey, are more often in danger than other parts of the body.
The tentacles are strong - by grabbing one, you can pull the entire octopus out of the hole. This is where the octopus “autotomizes” itself: the muscles of the captured tentacle contract spasmodically. They contract with such force that they tear themselves apart. The tentacle falls off, as if cut off by a knife. The predator receives it as a ransom for his life. Octopus Octopus defilippi perfectly mastered the art of autotomization. Grabbed by the hand, he immediately breaks up with her. The tentacle wriggles desperately - this is a false maneuver of a sacrificed kamikaze: the enemy rushes at him and misses the main target. The rejected tentacle still twitches for a long time, and if you let it go free, it even tries to crawl and can attach itself.
The octopus usually throws off about 4/5 of its entire arm, although it can tear off a tentacle in any other place. The lizard does not have such freedom of action: it breaks its tail only at a strictly defined point along a line predetermined by nature.
The wound at the site of the torn tentacle does not bleed, the blood vessels are strongly contracted and thereby seem to be pinching themselves. The skin at the end of the stump begins to quickly grow onto the wound and closes almost all of it. Approximately six hours after the autotomy, the blood vessels dilate, and blood begins to flow weakly from the wounded tissues, which in a dense clot, like a tampon, covers the operated surface of the tentacle, which is not yet covered with skin.
On the second day, the wound heals completely, and a new tentacle begins to grow in place of the lost organ. After a month and a half, it is already 2/3 closer to its nominal size.
Although autotomy is a fairly reliable method of life insurance, this method is very wasteful. Is it possible to come up with some less painful and more economical substitute for self-mutilation?
And such a replacement was found by nature.
In the process of evolution, cephalopods acquired a unique miracle weapon - an ink bomb. Instead of a piece of living flesh, the squid throws out a crude fake of itself in front of its open mouth to eat it. He seems to split into two before his eyes and leaves his ethereal double to the enemy, while he quickly disappears, very pleased with the trick.
But before we talk about this amazing device, the meaning of which was clearly deciphered by biologists only relatively recently, it is necessary, at least briefly, to describe what mollusk ink is, why and where it is formed, since it is from ink that squid make your double.
Ink Bomb
The ability of cephalopods to “show off” has long been known. In a moment of extreme danger, they eject a stream of black liquid from the funnel. The ink spreads in the water like a thick cloud, and under the cover of a “smoke screen” the mollusk more or less safely escapes the chase. Dives into some crevice or runs away, leaving the enemy to wander in the dark.
The ink contains organic dye from the melanin group, similar in composition to the pigment with which our hair is colored. The shade of ink is not the same in all cephalopods: in cuttlefish it is blue-black (in a strong dilution of the “sepia” color), in octopuses it is black, in squid it is brown.
Ink is produced by a special organ - a pear-shaped outgrowth of the rectum. It is called an ink sac. This is a dense bubble, divided by a septum into two parts. The upper half is reserved for the reserve tank, where ink is stored, the lower half is filled with the tissues of the gland itself. Her cells are filled with grains of black paint. Old cells are gradually destroyed, their paint dissolves in the juices of the gland - ink is obtained. They arrive at the “warehouse” - they are pumped into the upper bottle, where they are stored until the first alarm.
Not all the contents of the ink sac are sprayed out at once. An ordinary octopus can set a “smoke screen” six times in a row, and after half an hour it completely restores the entire spent supply of ink. The coloring ability of the ink liquid is unusually high. In five seconds, a cuttlefish paints with erupted ink all the water in a tank with a capacity of 5.5 thousand liters. And giant squids spew out so much inky liquid from the funnel that the sea waves become cloudy over a space of a hundred meters!
Cephalopods are born with a sac filled with ink. One almost microscopic cuttlefish, barely emerging from the egg shell, immediately colored the water with five ink volleys.
And this is an unexpected discovery that biologists have made in recent decades. It turned out that the traditional idea of a “smoke screen” of cephalopods should be thoroughly revised. Observations have shown that the ink discarded by cephalopods does not dissolve immediately, not before it hits something. They hang in the water as a dark, compact drop for a long time, up to ten minutes or more. But the most striking thing is that the shape of the drop resembles the outlines of the animal that threw it out. The predator grabs this drop instead of the fleeing prey. That’s when it “explodes” and envelops the enemy in a dark cloud. The shark becomes completely confused when a school of squid simultaneously, like 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 all disappears 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 already a few inches from the target, the squid suddenly darkened and, as it seemed to Hal, froze in place. The next moment, Hal grabbed... an ink model, which fell apart in his hands. The deceiver was floating at the other end of the tub.
Hal repeated his attempt, but now he was carefully watching the squid. When his hand approached again, the squid darkened again, threw out a bomb and immediately became deathly pale, then darted invisible to the far end of the tub.
What a subtle maneuver! The squid didn’t just leave its image in its place. No, it's a dress-up scene. First, he attracts the enemy's attention 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, changing his outfit. Please note: now his color is not black, but white.
Nature is cunning with inventions.
Wilhelm Schaefer believes that, apparently, there are two groups of cephalopods: some produce ink that quickly dissipates in water (such as a smoke screen), the ink of others depicts a rough model of their owner in the water (such as an ink bomb).
It seems to me that every mollusk, depending on the circumstances, can spew one or another type of ink. After all, in order to turn an ink bomb into a smoke screen, all it takes is a small obstacle against which it can first be smashed.
In 1878, Frederick wrote that the cuttlefish sepiola throws out ink drops similar in shape to itself, and thanks to this imitation it escapes from predators. But this observation was not given any significance. This often happened with other discoveries that go against the generally accepted opinion of some octopuses inside the funnel there is such an obstacle: a valve that blocks its lumen. When a bomb needs to be released, the valve can be pressed tightly against the wall of the funnel. If the clam lifts it slightly, it will cut the bomb into small fragments while still inside the siphon, and a scattered cloud of ink will erupt out.
There may be other ways to pre-detonate a bomb: for example, a stronger and sharper, under greater pressure, ejection of ink, or pulsating (“chewing”) movements of the funnel itself. It is possible that the mysterious “organ of the funnel” takes part in the transformation of one form of ink into another - a figured thickening on its inner wall, the purpose of which is still only dubious guesses.
The octopus has it all
Even newborn octopuses are not left unarmed. While their own means of combat have not yet developed, the little ones arm themselves with the poisonous arrows of jellyfish. The German scientist Adolf Näf caught larvae of tremoctopus - miniature pelagic octopuses - in the Mediterranean Sea and was surprised to find that each larva held in front of it in its weak “hands” a barrier of scraps of jellyfish tentacles. Nef decided that the stinging cells that line the jellyfish's tentacles serve the octopus babies as weapons.
Does any other living creature possess such a variety of protective instincts and such perfect “combat technology” as cephalopods?
They have: 1) eight (or ten) muscular arms; 2) there are claws on the hands and 3) hundreds of suction cups; 4) predatory beak; 5) poison; 6) eyes as keen as those of an eagle; 7) infrared vision; 8) “jet engine”; 9) the ability to soar over the sea; 10) a supply of water in the bosom for traveling overland; 11) autotomy; 12) regeneration of severed tentacles; 13) smoke screen; 14) ink “scapegoat”; 15) a drug for predatory fish; 16) the most advanced camouflage in the world and, finally, 17) flamethrowers, searchlights and identification lights (we will learn about them in the next chapter).
The cobra is armed only with poison, the boa constrictor with the strength of a mighty body, the hare and doe with the speed of its legs, the eagle with its beak and claws. And the octopus has eight legs, and has all the types of weapons listed above. Gilbert Klingel is right when he asserts: “If octopuses had been able to overcome the coastal barrier and emerge from the ocean onto land, they would probably have populated it with an endless variety of amazing organic forms.” No wonder Herbert Wells sired his Martians from octopuses.
Sucker power
Let's examine the octopus' suckers - its most dangerous weapon, according to general opinion. Each sucker is not a sucking mouth, as Victor Hugo thought, but rather a miniature medical jar. At the moment preceding suction, the muscular walls of the “can” contract, its cavity decreases; the bottom of the suction cup, similar to a piston, rises like a mound, approaching close to its opening, which fits tightly to the victim’s body. Then all the muscles of the suction cup quickly relax, the “piston” lowers - the internal cavity of the “can” increases, the pressure inside it drops sharply, and it is firmly sucked.
A suction cup with a diameter of 2.5 millimeters can hold 47 grams, and a suction cup with a diameter of 6 millimeters can hold almost 170 grams. On each octopus tentacle there are up to 100 or more of them (depending on the species and age of the animal). Let's say that on each tentacle an octopus has 100 suckers with a diameter of 6 millimeters. There will be 800 of them on eight tentacles. The weight that they are able to hold with their joint efforts is in this case 136 kilograms. Of course, this is only a theoretical calculation of the total suction force of the average octopus. In reality, all the suckers are never activated at the same time, and the animal’s muscles can hardly withstand a load of 100 kilograms.
Usually, on each tentacle, a dozen or more suction cups come into action. If an octopus grabs a person with, say, five tentacles, and holds on to rocks with the other three, then its 50 suckers, brought into contact with the enemy, will develop a “gravitational force” equal to eight and a half kilograms.
The force is small, but it is enough to pull an adult to you underwater. The approximate size of the suction cup holes in octopuses is about one and a half to two meters long. Depending on the species and sex of the animal, the size of the suckers varies greatly. Sucker of an octopus (top) and squid (bottom). The first, unlike the second, has a wide base and does not have a horny eyelid ring equipped with teeth (after all, a person loses more than 95 percent of his weight in water). But this is possible only under one indispensable condition - the captured person must not resist! If he jerks strongly, then the power of even eight hundred octopus suckers will not hold him back. With one hand, a strong person can make a jerk equal to the strength of 200 kilograms. The one-time popular circus strongman Eugene Sandow showed on a dynamometer a two-arm snatch force of 450 kilograms.
A man's fist, thrown forward in a strong blow, falls on the enemy with the weight of a twenty-pound weight. True, under water the resistance of the environment is much higher, and a person here is a weaker fighter than on land. However, even among the waves of the sea, as tests at Princeton University have shown, a good swimmer is not inferior in strength to a medium-sized shark (of course, without taking into account the fighting power of its teeth), which can easily cope with any octopus. It was more difficult to pull a swimmer tied to a line to shore than a shark or swordfish. The instruments calculated that a person “on a fishing rod” developed a pulling force of three hundred grams for every kilogram of his weight - almost twice as much as a shark.
It would hardly be worth using a series of these examples to prove the physical superiority of man over the octopus if the obviousness of this situation were clear to everyone. On the contrary, many works about octopuses are filled with dramatic episodes of the exact opposite nature.
The picture above shows the suction cup of an octopus, and below that of a squid.