“ghost” octopuses are under threat of extinction due to touching care for their offspring. Taking care of octopus eggs. Does a sand octopus take care of its offspring?

Savvy sea ​​chameleons- these are octopuses or octopuses! “Octopus - what a horror! - Sucks you out. He pulls you towards him, and into himself; you, tied up, glued together, feel yourself being slowly swallowed by this monster.” (Victor Hugo, “Toilers of the Sea”). Octopuses, or octopuses, have a bad reputation as underwater monsters.

Ancient legends and fantasy stories like this passage from Victor Hugo's novel portrays octopuses in a less than attractive light.

Octopuses and octopuses - sea chameleons

But in fact, even such a giant as the Pacific octopus, which can be up to 6 meters long and weigh almost 50 kilograms, is usually not formidable to humans.

IN last years various fictions and fables about octopuses as “monsters” have given way to the true stories of eyewitnesses - divers and ocean biologists who study these smart sea chameleons.

How do octopuses hunt?

Octopuses don't eat people. These sea ​​creatures eat for the most part crustaceans. To catch prey, they use their eight tentacles and 1,600 muscular suckers. A small octopus, using suction cups, can drag an object 20 times heavier than itself! Some octopuses have strong poison. During a hunt, the octopus almost instantly paralyzes its prey, and then calmly pushes it into its mouth, which has beak-like jaws.

What if an octopus sees someone trying to catch it? These creatures have one drawback: they blue blood contains hemocyanin instead of hemoglobin. Such blood does not carry oxygen well, so octopuses get tired quickly. And yet they manage to deftly escape from whales, seals and other predators.

How do octopuses defend themselves?

First, their “jet engine” comes to their aid. When the octopus sees danger, it sharply throws water out of the cavity of its body, and the reactive force thus formed pushes it back - away from the enemy.

This cautious creature can also resort to another trick: shooting a cloud of ink liquid at the attacker. This dye contains a pigment that is poorly soluble in sea ​​water. Therefore, while the clouds of “smoke” dissipate, the octopus has the opportunity to sneak unnoticed to a safe place.

Octopuses are skilled camouflages

The octopus does not like to be chased by predators - it prefers to hide. How he does it? Famous explorer underwater world Jacques-Yves Cousteau wrote: “In the coastal waters of Marseille, we began filming a film about octopuses.

However, most of our divers reported that there were no octopuses there at all, and if there once were, they had now disappeared somewhere. But in fact, divers swam near them but did not notice them, because they know how to skillfully camouflage themselves.” What helps octopuses become almost invisible?

Adult octopuses have about two million chromatophores, which means that on average there are up to 200 of these pigment cells per square millimeter of body surface. Each such cell contains red, yellow or black pigment. When an octopus relaxes or tenses the muscles around the chromatophores, it can almost instantly change color, even form different patterns on itself.

Oddly enough, it seems that the eyes of an octopus do not distinguish colors. However, he can “paint” himself in more than just three colors. And this is because iridocytes, cells with mirror crystals, reflect light, and the body of the octopus gains color in the areas of the bottom on which it is located. And that is not all. When he hides in coral reef, then he can even do his own smooth skin rough, forming spikes, and thus blending with the uneven surface of the coral.

Octopuses and octopuses are conscientious builders

Since octopuses love to hide, they build their houses in such a way that they are difficult to find. Basically, they make their homes in various crevices or under rocky ledges. The roof and walls are made from stone, pieces of metal, shells and even from the remains of ships and boats or from various rubbish.

Having such a house, the octopus becomes good owner. Using jets of water from his “jet engine,” he smoothes the sandy floor. And after eating, he throws all the leftovers out of the house outside.

One day, divers from Cousteau’s team decided to check whether the octopus was really good at managing the house. To do this, several stones were taken from the wall of his home. What did the owner do? Having found suitable cobblestones, he gradually built the wall!

Cousteau wrote: “The octopus worked until it restored what was destroyed. His house looked exactly the same, as did the divers' interventions." Indeed, octopuses are known for being able to build their homes well and maintain order in them. When divers see an octopus's house, which is full of various garbage, then they know: no one lives there.

Octopuses and octopuses - reproduction

The last and most important house in the life of a female octopus, this is the place where her offspring are born. Having received sperm from the male, the female stores it in her body until the eggs mature and are ready for fertilization. However, all that time she does not sit idly by, but spends several weeks searching for a suitable place for a nest.

When the house is ready, the female attaches a cluster of thousands of eggs to the ceiling. Only blue-winged octopuses do not make houses. Their bright color warns predators: our bite is very poisonous. Therefore, females prefer to care for their offspring in open places.

Female octopuses are caring mothers! Having laid eggs, the mother octopus stops feeding because new responsibilities have appeared. She relentlessly protects, cleans and rinses the eggs, repairs her nest, and when predators swim up, she takes on a threatening pose and drives them away.

The female takes care of the eggs until small octopuses emerge from them. After this she dies. Cousteau once said about this: “No one has ever seen a female octopus leave her eggs.”

Newborn octopuses of most species float to the surface of the sea and become part of the plankton. Many of them will be eaten by other sea creatures. But after a few weeks, the survivors will return to the bottom and gradually turn into adult octopuses. Their lifespan is almost three years.

Are octopuses smart and quick-witted?

Some people believe that if we say “smart” about an animal, then this only applies to its ability to learn from own experience and the ability to overcome any difficulties.

And here’s what Cousteau said about this: “Octopuses are timid, and this is precisely their “wisdom.” For them, it all comes down to caution and prudence... If a diver is able to show that he is not a threat, then the octopus quickly, even faster than other “wild” animals, forgets about its timidity.”

Among invertebrates, octopuses have the most developed brain and eyes. Eyes, like ours, can focus accurately and respond to changes in light. The vision region of the brain deciphers signals from the eyes and, along with its remarkable sense of touch, helps the octopus make surprisingly wise decisions.

Researchers reported that octopuses, in order to get their favorite dish- shellfish, they even manage to unseal the bottles. It is said that the octopus can learn to unscrew the lid on a jar to get food from it. And an octopus from the Vancouver Aquarium (Canada) every night made its way through a drainage pipe into neighboring reservoirs and caught fish there.

In the book “Exploring the Mysteries of Nature” (English), it is written about the ingenuity of octopuses: “We are accustomed to thinking that among animals the smartest primates. But there is a lot of evidence that octopuses are also smart animals.” These creatures are a real curiosity. Both scientists and divers, unlike Victor Hugo, no longer use the word “horror” about them.

Those who study octopuses have every reason to admire and wonder at this clever sea chameleon.

An octopus species unknown to science. An unusual creature received the nickname Casper for milky color and resemblance to a Disney character.

Marine biologists have come to the conclusion that due to a number of differences from their relatives, we can talk about the discovery of not only a new species, but also a whole new genus of octopuses. The fact is that this octopus lives at an incredible depth for cephalopods - more than four thousand meters. "Casper" has no fins, and all the suckers are located in one row on each limb, which is also uncharacteristic of octopuses. In addition, the representative of the new species completely lacks pigment cells - chromatophores. That is why the creature is almost transparent.

A team of scientists led by Autun Purser from the Institute of Polar and Marine Research. Alfred Wegener, observed 30 individuals using remotely operated underwater vehicles.

The discovery made by scientists turned out to be surprising and frightening at the same time. They managed to find out that “ghost” octopuses are characterized by unusual strategy parenthood. She would be a real gift for the scientific community, if not for one thing: precisely because of her unique look threatened with extinction.

Female "ghost" octopuses care for the eggs until the offspring hatch. Because of low temperatures, prevailing at great depths, this happens for quite a long time - sometimes up to several years (although after this it is difficult to surprise scientists with the timing).

At the same time, the strategy of caring for the offspring, as the researchers note, turned out to be incredibly touching for these octopuses: the female wraps her whole body around the eggs and protects them from other deep-sea inhabitants, without even swimming away to get food. She almost always ends up dying when the babies hatch.

But this was not the main threat to the new species. Observations have shown that “ghost” octopuses are accustomed to laying eggs on dead sponges - these are deep-sea multicellular organisms that lead an attached lifestyle. Near the Hawaiian Islands, where Casper was first spotted, these sponges attach to deposits of ferromanganese nodules - formations that contain a large number of valuable metals (manganese, copper and nickel), which are used, for example, in the production of mobile phones.

Sites ocean floor, covered with such deposits, . In this regard, the breeding area for octopuses is under threat.

Relatives of “Casper” are recognized as long-lived, which means that if the nodules and sponges living on them disappear completely, it will be almost impossible to restore the “ghost” octopus population. According to scientists, if this region begins to be used in industrial purposes, the local fauna will not recover even 26 years later. This, in turn, will harm the ecosystem as a whole, since octopuses feed on small organisms, the populations of which will unpredictably increase when the first ones disappear.

Scientists suggest that octopuses prefer to lay eggs on sponges near manganese deposits because of the connection with the source of food, as well as because of the safety of such locations (from the point of view Everyday life ocean), but this is only a hypothesis that remains to be tested.

So far, very little is known about “ghost” octopuses, and marine biologists intend to protect the ecosystem and rare view from extinction, because further study of it may provide valuable information. In addition, many more may live at great depths. unknown creatures, which will also suffer from anthropogenic activities.

Kir Nazimovich Nesis, doctor biological sciences

A chicken sits on eggs for 21 days. Great spotted woodpecker - only 10 days. Small passerine birds usually incubate for two weeks, and large predators- up to one and a half months. An ostrich (an ostrich, not an ostrich) hatches its giant eggs for six weeks. Female emperor penguin“stands” in the midst polar night a single egg, weighing half a kilo, nine weeks old. The record holder from the Guinness Book is the wandering albatross: he sits on the nest for 75-82 days. In general, eggs are small or large, in the tropics or in the Arctic, and all are laid in three months. But this is in birds.

Don't you want a year? How about two? A female sand octopus (Octopus conispadiceus) that lives in Primorye and northern Japan has been sitting on eggs for more than a year. The arctic octopus (Bathypolypus arcticus), common in our northern seas. It's actually incubating! It should be noted that only in very few birds does the female sit on the eggs constantly, and the male feeds her; in most cases, the hen runs away or flies away from time to time to feed a little. That's not what an octopus is like! She doesn't leave the eggs for a minute. In octopuses, eggs are oval and with a long stalk; different species vary greatly in size: from 0.6-0.8 mm in length - in pelagic Argonaut octopuses to 34-37 mm - in some Sea of ​​Okhotsk, Antarctic and deep-sea bottom octopuses. Pelagic octopuses carry eggs on their own hands, but bottom-dwelling octopuses are simpler in this regard - they have a burrow. The female weaves small eggs with the tips of her hands into a long cluster with stems and with a drop of special glue that hardens firmly in water, she glues each cluster (and there are more than one hundred of them) to the ceiling of her home; in species with large eggs, the female glues each one one by one.

And now the octopus sits in the nest and incubates the eggs. Well, of course, he doesn’t warm them with his body - octopuses are cold-blooded, but he constantly goes through them, cleans them (otherwise they become moldy), washes them with fresh water from the funnel (the jet nozzle under the head) and drives away all sorts of small predators. And all this time he eats nothing. And she can’t eat anything - wise nature decided not to tempt the starving female with the proximity of such fatty, nutritious and, probably, tasty eggs: shortly before laying them, all incubating octopuses completely stop producing digestive enzymes, and therefore nutrition. Most likely, your appetite disappears completely! Before breeding, the female accumulates a reserve nutrients in the liver (like a bird before migrating) and consumes it during incubation. By the end she is exhausted to the limit!

But before she dies, she has one more important task to do: help her octopuses hatch! If you take the eggs from the female and incubate them in an aquarium, they develop normally, except that there is a little more waste (some of the eggs will die from mold), but the process of eggs hatching from the clutch is greatly extended: from the birth of the first octopus to the last it can take two weeks , and two months. With a female, everyone is born on the same night! She is giving them some kind of signal. And before hatching, octopuses see perfectly and move quickly in their transparent cell - the egg shell. The octopuses hatched (pelagic larvae - from small eggs, bottom crawling juveniles - from large eggs), spread out and spread out - and the mother dies. Often - the next day, rarely - within a week. I held on with my last strength, poor thing, just to have children in great life direct.

How long does she have the strength to last? Octopuses have been kept in aquariums for a long time, and there are many observations of their reproduction, but in the vast majority of cases they were made on inhabitants of the tropics and temperate waters. Firstly, heating water in aquariums to tropical temperatures is technically easier than cooling it to polar temperatures, and secondly, catching a deep-sea or polar octopus alive and delivering it to the laboratory is also not easy. It has been established that the duration of incubation of octopus eggs ranges from three to five days for tropical argonauts with the smallest eggs and up to five to six months for octopuses of temperate waters with large eggs. And, as I already said, two species have more than a year!

The duration of incubation depends on only two factors: egg size and temperature. Of course, there are specific features, but they are small. This means that the incubation period can also be calculated for those species that have not yet been possible to grow in an aquarium, and it is unlikely that they will be able to grow it soon.

This is especially interesting for our country. Only one or two species of benthic octopuses from Sea of ​​Japan(near the southern part of Primorsky Krai) eggs are small and develop at the stage of planktonic larvae. The giant North Pacific octopus (Octopus dofleini) has medium-sized eggs and is also a planktonic larva. And everyone else has large and very large eggs, direct development (the eggs hatch into juveniles similar to adults), and they live at low or very low temperatures. The sand octopus has large eggs, 1.5-2 cm, but far from being record-breaking. In the northeast of Hokkaido (where by Japanese standards it’s almost the Arctic, but by ours it’s quite a cozy place, you can even swim in the summer) a female with an egg laying life lived in an aquarium for almost a year, although she was caught already developing eggs, and if with freshly deposited ones, I could probably do one and a half. Arctic Bathypolypus - a resident of the Arctic - was kept in an aquarium in Eastern Canada, where it is not very cold. This means that in our waters and for our octopuses, a year is not the limit! Let's try to calculate, but how much?

Calculate the duration of incubation cephalopods Z. von Boletsky tried in cold waters. He extrapolated a graph of incubation time versus temperature for inhabitants of temperate waters towards low temperatures. Alas, nothing came of it: already at +2°C the line for the octopus went to infinity, and for squids and cuttlefish with eggs of much smaller octopuses it reached the region of one to three years. But in the Arctic and Antarctic, octopuses successfully hatch their offspring even at subzero temperatures. They haven't been doing this for decades!

V.V.Laptikhovsky from the Atlantic Research Institute fisheries and oceanography in Kaliningrad brought together all available information on the duration of embryonic development of cephalopods and developed mathematical model, which relates the duration of incubation to egg size and water temperature. We know the size of the eggs for almost all octopuses in our waters, the temperature of their habitat as well, and Volodya Laptikhovsky explained to me some of the “pitfalls” of his formulas. This is what happened.

The sand octopus in the South Kuril shallow waters, at a depth of about 50 m, incubates its eggs, according to calculations, for more than 20 months, and the giant North Pacific octopus on the edge of the Bering Sea shelf - a little less than 20 months! This coincides with the data of Japanese scientists: giant octopus, which incubates eggs off the western coast of Canada for six months, would do this for a year and a half on the coast of the Aleutian Islands, and sand octopus near Hokkaido, at a depth of 50-70 m, one and a half to two years. The Arctic bathypolypus in the Barents Sea incubates eggs, according to estimates, for two years and a week, and the fishing benthoctopus (Benthoctopus piscatorum - so called by the American zoologist A.E. Veril in gratitude to the fishermen who brought him this deep-sea inhabitant) on the slope of the Polar Basin - 980 days , almost three years. Graneledone boreopacifica at a kilometer depth in the Sea of ​​Okhotsk - two years and two months, tubercular bathypolypus sponsalis and different types benthoctopus in the Bering and Okhotsk Seas - from 22 to more than 34 months. In general, from one and a half to almost three years! Of course, this is an estimate, because the size of the eggs varies within certain limits, and the temperature of the bottom water is different at different depths, and Laptikhovsky’s formula may not work well at very low temperatures, but the order of magnitude is clear!

It has long been suggested that polar and deep-sea animals have some kind of metabolic adaptations to low temperatures, so that the rate of metabolic processes in their eggs is higher than in the eggs of animals from temperate latitudes, if they were placed in water with a temperature close to zero. However, numerous experiments (though not with octopuses, but it is unlikely that octopuses have a different physiology than crustaceans and echinoderms) have not revealed any metabolic adaptation to cold.

But maybe deep-sea octopuses do not sit on their eggs as inseparably as shallow-water octopuses, but crawl around and feed? Nothing like this! Both me and my colleagues have more than once come across female tuberculate bathypolypus in trawls with eggs neatly glued to dead deep-sea glass sponges (very reliable protection: A glass sponge is as “edible” as a glass glass). Imagine the horror of a small, palm-sized octopus when, with a grinding sound, surrounded by frightened fish, a monster of incredible size approaches it - a fishing bottom trawl. But the female doesn’t throw eggs! And female Arctic Bathypolypus in a Canadian aquarium honestly sat on their eggs in constant care for them for a whole year until the young hatched.

True, neither I nor my colleagues have ever seen female benthoctopus and graneledon with eggs in trawl catches. But we have repeatedly come across large females of these octopuses with a flabby, rag-like body and a completely empty ovary. Most likely, these were brooding (scavenging, i.e., scavenging eggs) females, frightened off their eggs by the approaching trawl. But we have never seen the eggs they swept. They probably hide them well.

It is believed that, apart from octopuses, no other cephalopods guard laid eggs (they don’t even bury them in the ground, like crocodiles and turtles). How long does it take for their eggs to develop?

So far we have talked about finless, or ordinary, octopuses, but there are also finned ones. These are deep-sea, very strange-looking octopuses - gelatinous, like a jellyfish, and with a pair of large, spaniel-like ears, fins on the sides of the body. Cirroteuthis muelleri lives in the depths of the Norwegian, Greenland Seas and the entire Central Polar Basin, right up to the Pole - on the bottom, above the bottom and in the water column. At rest, it looks like an open umbrella (when viewed from above), and when fleeing from danger, with folded hands, it looks like a bell flower (when viewed from the side). Two species of opisthoteuthis - inhabitants of the Bering Sea, Sea of ​​Okhotsk and the North Pacific. These octopuses at rest, lying on the bottom, look like a thick, fluffy pancake with “ears” on the top of the head, and when swimming and hovering above the bottom, they look like a wide tea cup. All of them have large eggs, 9-11 mm long. The female lays them one at a time directly to the bottom and does not care about them anymore, and there is no need: they are protected by a dense chitinous shell, similar to a shell, and so strong that they can even withstand being in the stomachs deep sea fish. The duration of development of these eggs, according to calculations, is no less than that of common octopuses, protecting the masonry: 20-23 months at the bottom of the Bering and Okhotsk seas, 31-32 months in the depths of the Polar Basin!

The largest eggs of all cephalopods are those of the nautilus (Nautilus pompilius). The same one whose name was taken by a once unknown, but now famous rock band. It is unlikely that the guys have ever seen a living nautilus: it is not our fauna, it lives in the tropics of the eastern part of the Indian and western parts Pacific Oceans, on the slopes of coral reefs. And they certainly didn’t know that he was the cephalopod world record holder for egg size. In the nautilus they reach 37-39 mm in length and are surrounded by a very durable leathery shell. The female lays them on the bottom one by one with long (two weeks) breaks. Usually nautiluses live at depths of 100-500 m at a temperature of 10-15°C, but to lay eggs the female rises to the shallowest water, where the temperature is 27-28°. Yes, he hides them so cleverly that, no matter how much research has been carried out on the reefs, no one has yet found nautilus eggs in nature. We saw only freshly hatched juveniles slightly larger than the current five-ruble. But in aquariums, nautiluses live well and lay eggs, but they do not develop. Only recently, after many failures, in aquariums in Hawaii and Japan it was possible to find the necessary temperature regime and get normally hatched fry. The incubation period turned out to be 11-14 months. And this is with almost tropical temperature!

Cuttlefish also lay eggs on the bottom and either camouflage them by painting them black with their own ink, or tie them with a stem to stinging lobed soft corals (so that the egg sits on a coral branch, like a ring on a finger), or glue them to the bottom, hide under empty shells shellfish And our ordinary northern cuttlefish from the genus Rossia (Rossia - not in honor of our country, but after the English navigator of the early last century, John Ross, who first caught the northern cuttlefish Rossia palpebrosa in the Canadian Arctic) stuff eggs covered with durable calcareous shells into soft flint-horned sponges. According to calculations, the duration of incubation of eggs in the Pacific (R. pasifica) and northern russians(R. palpebrosa, R. moelleri) at a temperature of 0-2°C for about four months. However, in the aquarium of the American city of Seattle, the eggs Pacific Russia developed for five to eight months at a temperature of 10°C, so in reality the duration of their incubation in our northern and Far Eastern seas may be significantly more than six months.

It’s hard to believe, but among mollusks there are species that, although in a rather primitive form, nevertheless take care of their offspring. And the small calyptrea snail, which lives in warm seas at shallow depths.

And although she does not dig holes or build nests, she nevertheless does not abandon her offspring to the mercy of fate.

The mother snail packs the laid eggs into special capsules, which it then covers with its shell and partly with its foot.

Something similar to the desire to show care for the offspring can also be seen in some keelfoot mollusks. These peculiar maternal instincts is that the eggs, released by the female during reproduction, are attached to a light cylindrical thread, the end of which is located inside the mollusk. That is, it turns out that for some time the eggs continue to swim behind the female, thus remaining under her, although not very reliable, but still protection.

Octopuses demonstrate a special and very responsible attitude towards their offspring. It has long been noticed that the females of these mollusks are very attached to their clutch. And so much so that when they incubate the eggs, they starve for many weeks and even months. Only a few females allow themselves to have a snack near the protected eggs.

These hunger strikes are caused by the need to protect the eggs from contamination. And for this, first of all, there must be clean water. Any organic matter that may rot is immediately removed from the nest. Therefore, fearing that waste may get from the “dining table” into the nest, the females starve. In addition, they constantly wash the masonry with fresh water, spraying it with a stream from a funnel on their body.

Before laying eggs, females look for well-protected and inconspicuous places. Usually for small octopuses such shelters are oyster shells. First, the octopus eats the owner of the shell, and then climbs inside, attaches itself to both of its flaps and in this position keeps them tightly closed.

Among zoologists for a long time There has been debate about how octopuses manage to open the tightly compressed shells of their prey. But even the Roman naturalist Caius Pliny suggested that the octopus spends a long time next to the oyster shell, waiting for it to open the valves. And, as soon as the mollusk can’t stand it and opens its “house”, the octopus throws a stone inside. After this maneuver, the mollusk can no longer close the shell valves, and the octopus first calmly feasts on the hostess, and then settles in her home.

Most scientists reacted to this version of Pliny with a fair amount of skepticism. But when they observed the octopuses in the aquarium, the legend of throwing stones had to be accepted as true.

But the octopus uses stones not only when hunting oysters. He also uses them when building his nests. In this case, he demolishes the stones, as well as the shells and shells of the crabs he has eaten, into one pile, and makes a depression on top of it, in which he hides.

And in case of a threat, he doesn’t just hide in his stone cave, and also covered from above, like a shield, with a large stone.

Octopuses build their “castles” at night. During construction, they sometimes drag in quite massive stones. At least some of them weigh several times more than the animals themselves. In some areas of the seabed, an entire “town” is formed from such nests. One of these settlements was described by the famous aquanaut J. Cousteau:

“On the flat bottom of a sandbank northeast of the Porquerolles Islands we attacked a city of octopuses. We could hardly believe our eyes. Scientific data, confirmed by our own observations, indicated that octopuses live in crevices of rocks and reefs. Meanwhile, we discovered bizarre buildings, clearly built by the octopuses themselves. A typical design had a roof in the form of a flat stone half a meter long, weighing about eight kilograms.

On one side, the stone rose about twenty centimeters above the ground, supported by a smaller stone and debris building bricks. A recess twelve centimeters deep was made inside.

In front of the canopy a shaft of all sorts of things stretched out construction waste: crab shells, oyster shells, clay shards, stones, as well as sea ​​anemones and hedgehogs.

Leaning out of the house long arm, and above the shaft the owl eyes of an octopus were looking straight at me. As soon as I approached, the hand moved and moved the entire barrier towards the entrance hole. The door closed. We filmed this “house” on color film. The fact that the octopus collects building materials for its house, and then, lifting a stone slab, places supports under it, allows us to conclude that its brain is highly developed.”

But if octopuses build shelters for themselves and their offspring from stones, then some species bivalves make nests from their byssus.

Moreover, on the outside they inlay them with pebbles, fragments of shells or pieces of seaweed.

Similar “nests” can be built from threads of their byssus and pieces of algae by some species of the genus Musculus, which is close to Modiolas.

They lay the mucous cords of their oviposition in such a nest. Moreover, in these nests the embryos develop without passing through the stage of a free-swimming larva. Thus, in this case, there is one type of care for the offspring.

The sea scallop, the gaping lima, exhibits special abilities in this matter. It holds together small fragments of shells, tiny pebbles, and pieces of coral with a byssus. Then the lima lines the inside of its home with the same thin threads of yarn, turning it into a cozy, bird-like nest.

But one of the snails living on Sangir Island lays eggs between the bent halves of a leaf; All the manipulations necessary to prepare such a house are performed by the snail with its foot, and the secreted mucus plays the role of cement here.

From the book “100 Great Animal Records”, author Anatoly Bernatsky

Cephalopods are the most highly organized of all representatives of their phylum. Class Cephalopods ( Cephalopoda) is divided into two subclasses: fourgills ( Tetrabranchia) with a single order, family and genus of Nautiluses ( Nautilus) and bibranchs ( Dibranchia) with four orders: octopuses ( Octopoda), vampires ( Vampyromorpha), cuttlefish ( Sepiida) and squid ( Teuthida).

Even the most primitive of cephalopods - nautiluses - take care of their offspring. For example, females Nautilus pompilius, which lay the largest eggs among cephalopods (up to 4 cm in length), carry out this process very responsibly. The female lays eggs on the bottom one by one with long (about two weeks) breaks. Typically, nautiluses live at depths of up to 500 m, but to lay eggs they rise to the shallowest waters, where the temperature reaches 27–28 °C. At the same time, the female hides her eggs so carefully that until now not a single researcher has seen nautilus eggs in nature. Only recently, after many failures, were these mollusks able to be propagated in aquariums. It turned out that the incubation period of their eggs is 11–14 months.

The eggs of some species of octopuses take no less time to develop. Moreover, the females of many representatives of this order “hatch” their clutch, not leaving it for a minute: they constantly sort through the eggs, clean them, and wash them with fresh water from a funnel. In some species, the female, with her sensitive tentacles, carefully weaves the stalks of small eggs into a long cluster and, with a drop of special glue, attaches it to the ceiling of an underwater cave, in which there can be more than one hundred such clusters. In species that lay large eggs, the female attaches them to the ceiling one by one.

During the entire period of egg development, females of “brooding” octopus species do not feed, accumulating a supply of nutrients in their bodies in advance. Before reproduction begins, their production of digestive enzymes completely stops.

Female sand octopus ( Bathypolypus arcticus), living in the waters of Primorye and near Northern Japan, takes care of its clutch for about a year. And the arctic octopus bathypolypus ( Bathypolypus arcticus), living in our northern seas, “hatches” eggs for 12–14 months. After the babies are born, the exhausted female dies. A similar phenomenon - death after the completion of a single reproductive cycle - is generally very typical for female cephalopods. But their males sometimes survive 2-3 breeding seasons.

Before her death, the female octopus must help the babies hatch from the eggs. In an aquarium, without a mother, the hatching process of octopuses is very protracted and up to two months pass from the birth of the first baby to the hatching of the last one in the same clutch. When the mother is alive, the cubs are born in one night. Perhaps the octopus gives them some kind of specific signal, because before hatching, small mollusks already see well and move quite actively in their transparent egg shell.

Cephalopod eggs: 1 - Eledone; 2 - Cirroctopus; 3 - Loligo; 4 - Sepia

Other representatives of bibranched cephalopods do not incubate eggs as carefully as octopuses, but show concern for their safety in other ways. For example, cuttlefish, laying their eggs on the bottom, camouflage them either with ink, or by covering the clutch with empty mollusk shells, or even by tying the eggs to the stems of stinging corals. One species of cuttlefish stuffs its eggs into soft flint-horned lips. Development of cuttlefish eggs in northern waters may will probably continue for more than six months.

As for squid, in known oceanic species the clutch is a gelatinous formation with eggs suspended in it. In the most important commercial species Todarodes pacificus And Illex illecebrosus These are huge, 1 m in diameter, balls of transparent mucus, which contain hundreds of thousands of small eggs. And the little firefly squid ( Watasenia scintillans) these are two transparent strings of mucus that contain mollusk eggs. In warm and temperate warm waters Small squid eggs develop in 5–10, sometimes up to 15 days.