Does a sand octopus care for its offspring? How cephalopods take care of their offspring. Octopuses are smart and quick-witted

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

How do cephalopods care for their offspring?

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

Even the most primitive of cephalopods - nautiluses - take care of their offspring. For example, females of Nautilus pompilius, which lay the most large eggs(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 reserve in their body in advance nutrients. Before reproduction begins, their production of digestive enzymes completely stops.

The female sand octopus (Bathypolypus arcticus), which lives in the waters of Primorye and near Northern Japan, takes care of her clutch for about a year. And the Arctic octopus Bathypolypus arcticus, which lives 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 is giving them some kind of specific signal, because before hatching, small mollusks already see well and move quite actively in their transparent egg shell.

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 could probably last 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 in the small firefly squid (Watasenia scintillans) these are two transparent strings of mucus, which contain mollusk eggs. In warm and temperate warm waters Small squid eggs develop in 5–10, sometimes up to 15 days.

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.

Researchers in California have found that octopuses can care for eggs in a nest for four and a half years - longer than other known animals. During this time, the female octopus cares for her offspring, constantly cleaning the eggs from dirt and protecting them from predators. Often, if there is a lack of food, it dies after the eggs hatch.

Scientists from MBARI have been conducting ocean floor surveys every few months for the past 25 years, observing the life of deep-sea animals in the Monterey Canyon area. During one of these dives in May 2007, experts discovered a female octopus at a depth of 1.4 thousand meters on one of the rocky ledges. It was a representative of the species Graneledone boreopacifica. She wasn't here a month before.

Over the next four and a half years, researchers made 18 dives in this place. Each time, scientists could observe the same octopus (biologists identified it by special markings). A few years later, the translucent eggs laid by the female increased in size, and experts were able to see small octopuses inside. After four years, the female lost weight and her skin became pale. During the dives, the researchers never saw the female eating. Moreover, she did not even show interest in the small crabs and shrimp swimming past.

The last time scientists saw the female was in September 2011. A month later, the octopus was no longer there. Judging by the remaining egg shells, the young octopuses had recently hatched and the female had left the area. After counting the remains of the eggs, the researchers came to the conclusion that there were about 160 of them.

Most female octopuses lay eggs only once in their lives. The eggs of Graneledone boreopacifica are teardrop-shaped. They are the size of small olives. Little octopus The inside of the egg requires a lot of oxygen, so the female must constantly provide a flow of fresh water to the nest, preventing dirt and silt from entering it.

Because young octopuses spend a lot of time in the egg, they hatch fully formed. After hatching, they can hunt small prey on their own. The hatched juvenile Graneledone boreopacifica is better developed compared to representatives of other species of octopus and squid. Octopus eggs, like many other invertebrates, are kept in cold sea water, which slows down their development. The water temperature at the depth of Monterey Canyon is about 3 degrees Celsius.