Does a sand octopus care for its offspring? Octopuses and octopuses are sea chameleons. Octopuses are skilled camouflages
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 are expressed in the fact 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
He has no equal in the art of camouflage. Is he capable of thinking? Does he have consciousness? Some scientists believe this is quite possible.
Imagine that you are plunging into the sea off the coast of the Indonesian island of Lembeh. It’s shallow here—about five meters—and everything is flooded with sunlight. The water is very warm - as it should be in a tropical paradise. The bottom is covered with wavy fine dark gray sand with greenish spots of silt. Looking around the area, you notice a lone bivalve, quite massive. Six sharp spines protrude from it: perhaps the owner of the shell is hiding inside. Or maybe he died a long time ago, and now a hermit crab has settled in the bivalve. Out of curiosity, you decide to turn the shell over... But instead of snail horns or stalked eyes of a crayfish, large, almost human eyes, surrounded by a halo of tentacles with suction cups, look at you. Here is an octopus, namely the coconut octopus (Amphioctopus marginatus), so nicknamed for its loyalty to the coconut shell - it is in it that it prefers to hide. Sometimes this mollusk even travels with its shelter - after all, it may well come in handy in case of danger. However, if he comes across an empty shell, he will take it too. “These animals are walking pieces of meat, a kind of filet mignon in sea depths».
Having secured itself with suction cups, the octopus carefully holds the doors. You continue to watch and notice that, having slightly loosened his grip, he pulls himself up and sticks out: he assesses the situation. Freezing so as not to scare away a mollusk the size of thumb, you see how he, making sure that there is no danger, leaves the shell. Moving through the sand, the octopus becomes as dark gray as the soil. Has he really decided to leave? Not at all: crawling along the sand, the mollusk climbs onto the shell. Then, with a deft movement, he turns it over and crawls inside again. You were about to decide to swim away, when suddenly a barely noticeable movement catches your eye: an octopus, with streams of water, washes away the sand under the shell until a gap forms there. And now our hero is already looking out from under the shell. You lean closer and your eyes meet. He looks into your eyes carefully, as if studying you. Yes, among invertebrates, octopuses have perhaps the most human features. Even among vertebrates, you rarely see such an intelligent, searching gaze: try to imagine some fish trying to look into your soul!
The spots on the body of the nocturnal octopus Callistoctopus alpheus are sacs filled with pigments. If the clam decides to open them all, its skin will be covered with a pattern of white polka dots on a red background.
Octopuses also resemble people in that they are famous for their agility - with the help of tentacles strewn with hundreds of suckers, they can manipulate objects just as well as we can with our fingers, easily open bivalve shells, unscrew lids from jars, and even disassemble the water filtration system in aquariums. This sets them apart from marine mammals, after all, the same dolphins, although smart, are very limited by the anatomy of the body - with all the desire and intelligence, they cannot open the jar. At the same time, it’s hard to imagine creatures more unlike us: did you know that an octopus has three hearts and blood of blue color? What about the fact that they don’t have a skeleton? A parrot-like beak and dense cartilage that protects the brain are all the hard parts of the body. Therefore, they easily penetrate through cracks and can escape from almost anywhere. And each sucker is capable of moving independently of the others and is covered with taste buds - as if the human body were studded with hundreds of tiny tongues. And in the skin of a mollusk many light-sensitive cells are concentrated. But this is not the most alien quality of cephalopods. Before we reveal all the cards, let's get to know the representatives of this tribe better. If humans belong to the class of mammals, then octopuses also belong to the class of cephalopods (Cephalopoda). The name of the class perfectly reflects the essence of their anatomy: the “legs,” that is, the tentacles, are on one side of the large head, growing from it, and the short, bag-like body is on the other. The class Cephalopods refers to a phylum of molluscs that also includes gastropods (snails and slugs), bivalves (mussels and oysters), polyvalve chitons, and several lesser-known classes. Their history goes back half a billion years and begins with a tiny creature with a cap-like shell. After 50 million years, these mollusks already dominated the ocean, turning into the largest predators. Some individuals reached enormous sizes - for example, the length of the shells of the giant endoceras (Endoceras giganteum) exceeded five meters. The planet is now inhabited by more than 750 known to science cephalopod species. In addition to 300 species of octopuses, this class includes squid and cuttlefish (with 10 tentacles each), as well as several species of nautiluses - unusual mollusks with ninety tentacles that live in a multi-chambered spirally coiled shell. Representatives of this genus are the only direct descendants of the most ancient external-shell cephalopods.
Modern octopuses are very diverse: from the giant North Pacific octopus (Enteroctopus dofleini), whose tentacle alone can reach two meters in length, to the tiny Octopus wolfi, whose mass does not exceed 30 grams. Shallow-water species prefer to settle among corals, stay in muddy pools or hide in the sand, emerging only to get from one point to another, or to escape predators. Kinds open sea They cut through the sea, following ocean currents. They are found everywhere - from the tropics to the polar regions. Let us return, however, to the shores of Lembeh Island. A new day is just beginning Sun rays penetrate the water column. You are sailing over a coral reef located at shallow depths. Local guide Amba gives you a sign that he has spotted an octopus, and quite a large one at that. You look around, trying in vain to see the mollusk, but you see only rocks covered with corals and colorful sponges. Amba insists, gesturing: “Big!” You look where he points his finger, but you still don’t see anything. However, taking another look at the dark velvety coral, you realize that it is not any coral, but a blue octopus (Octopus cyanea). And why didn’t you immediately notice this creature, the size of a serving dish! Many animals hide, merging with the objects around them - for example, that orange sponge over there is actually not a sponge at all, but an angler fish, hiding in anticipation of unwary prey. A leaf floating at the bottom is not a leaf at all, but also a fish pretending to be a leaf. The bright sea anemone is by no means a poisonous polyp, but a harmless sea slug that cleverly confuses everyone with its appearance. But a small section of the seabed suddenly took up and floated - in fact, it was a flounder, merging in color with the ground. But even in such company, octopuses and cuttlefish (and also, to a lesser extent, squid) have no equal in the art of camouflaging on the move, or rather, while afloat - one moment they look like coral, the next a ball of snakes, and the next minute you can’t see them anymore on a sandy bottom. They adapt so skillfully to the surrounding objects that it seems as if they are using their body and skin to create three-dimensional images of various objects. How do they do this?
Photo: Many species of cephalopods are poisonous to varying degrees, but the venom of the southern blue-ringed octopus Hapalochlaena muculosa can be fatal to humans. Author: David Liittschwager; photo taken at Pang Quong Aquatics, Victoria, Australia"> 
Many species of cephalopods are poisonous to varying degrees, but the venom of the southern blue-ringed octopus, Hapalochlaena muculosa, can be fatal to humans.
Photo: David Liittschwager; photograph taken at Pang Quong Aquatics, Victoria, Australia
Photo: Pacific red octopus (Octopus rubescens) showing off its suckers. Each of them can move independently of the others, bend and twist in such a way as to provide tight suction, impressive strength and enviable agility. Author: David Liittschwager, photos taken at Dive Gizo, Solomon Islands"> 
Pacific red octopus (Octopus rubescens) showing off its suckers. Each of them can move independently of the others, bend and twist in such a way as to provide tight suction, impressive strength and enviable agility.
Photo: David Liittschwager, taken at Dive Gizo, Solomon Islands
Photo: Most octopuses grow very quickly - the photo shows a young blue octopus (Octopus cyanea). Author: David Liittschwager, photograph taken at Dive Gizo, Solomon Islands"> 
Most octopuses grow very quickly - the photo shows a young blue octopus (Octopus cyanea).
Photo: David Liittschwager, taken at Dive Gizo, Solomon Islands
Octopuses have three degrees of protection (camouflage). The first is color mimicry - pigments and reflectors are used for it. The pigments are granules of yellow, brown and red colors and are located inside numerous sacs in top layer skin (there can be several thousand of them, and when closed they look like tiny spots). To change color, the clam squeezes the muscles around the pouches, pushing them outward, where they expand. By deftly controlling the size of the pouches, the octopus is able to change patterns on the skin - from spots to wavy lines and stripes. Reflector cells are of two types: the first simply reflect the rays falling on them - in white light they are white, in red light they turn red. Cells of the second type are similar to the film of a soap bubble: they shine different colors depending on the angle of incidence of light rays. Together, pigments and reflective cells allow the octopus to create a full range of colors and complex patterns. The second element of the camouflage system is skin texture. By engaging certain groups muscles, octopuses easily transform the smooth surface of the body into lumpy or even spiky. For example, Abdopus aculeatus imitates algae so plausibly that without some skill it is almost impossible to distinguish it from a plant. The third secret that allows octopuses to remain undetected is their soft body, which can transform into anything. For example, curl up into a ball and slowly move along the bottom, depicting a piece of a coral reef: “Like, I’m not a predator, but just a lifeless block.”
I wonder if octopuses understand what needs to be depicted at any given moment? An ordinary freshwater snail has about 10 thousand neurons, lobsters have about 100 thousand, and jumping spiders have 600 thousand. Bees and cockroaches, the leaders in the number of neurons among invertebrates - naturally, after cephalopods - have about a million. The nervous system of the common octopus (Octopus vulgaris) consists of 500 million neurons: this is a completely different level. In terms of the number of neurons, it significantly exceeds mice (80 million), as well as rats (200 million) and can easily be compared with cats (700 million). However, unlike vertebrates, in which most neurons are concentrated in the brain, in cephalopods two thirds of all neurons nerve cells concentrated in the tentacles. Another important fact : The higher the level of development of the nervous system, the more energy the body spends on its functioning, so the benefits should be worth it. Why do octopuses need 500 million neurons? Peter Godfrey-Smith is a philosopher by training but now studies octopuses at the City University of New York and the University of Sydney. He believes that the emergence of such a complex nervous system is due to several reasons. Firstly, this is the structure of the octopus’s body - after all, the nervous system is transformed as the whole organism develops, and the octopus’ body is unusually complex. The mollusk can turn any part of the tentacle wherever it wants (it has no bones, which means there are no limiting joints). Thanks to this, octopuses have complete freedom of movement. In addition, each tentacle is capable of moving independently of the others. It is very interesting to watch the octopus during the hunt - it lies on the sand with its tentacles spread out, and each of them carefully examines and searches the area allocated to it, without missing a single hole. As soon as one of the “hands” stumbles upon something edible, for example a shrimp, the two neighboring ones immediately rush to the rescue so as not to miss the prey. The suction cups on the tentacles can also move independently of each other. Add to this the need for constant monitoring of skin color and texture; processing a continuous stream of information coming from the senses - taste and tactile receptors on the suction cups, organs of spatial orientation (statocysts), as well as from very complex eyes - and you will understand why cephalopods need such a developed brain. Octopuses also need a complex nervous system for navigation, because their usual habitat – coral reefs – has a rather complex spatial structure. In addition, mollusks do not have a shell, so you have to constantly be on alert and watch out for predators, because if the camouflage suddenly does not work, you will need to immediately “make your moves” to take refuge in a shelter. “These animals are walking pieces of meat, like filet mignons in the depths of the sea,” explains Mark Norman, a world-class expert on modern cephalopods from the Victoria Museum in Melbourne. And finally, octopuses are fast, agile hunters with a wide range of taste preferences. They eat everything from oysters, hidden in powerful shells, to fish and crabs, which are not a miss themselves: with strong claws or sharp teeth. So, a body without bones, a difficult habitat, a varied diet, the need to hide from predators - these are the main reasons, according to Peter Godfrey-Smith, that led to the development mental abilities cephalopods. Being the owners of such a developed nervous system, how smart are they? Assessing the level of intelligence of animals is not an easy task; often in the course of such experiments we learn more about ourselves than about the individuals being studied. Traditional signs by which the presence of intelligence in birds and mammals is assessed, such as the ability to use tools, are not suitable in the case of octopuses, because the main tool for these mollusks is their own body. Why would an octopus make something to extract a treat from a hard-to-reach crevice or use foreign objects to open an oyster? For all this he has tentacles. Tentacles are tentacles, but back in the 1950s and 1960s, scientists began conducting experiments during which they found that octopuses are well trained and have good memory - and these are two main signs of intelligence. Roy Caldwell, who studies octopuses at the University of California (Berkeley), says: “Unlike the smartest common octopus (Octopus vulgaris), many of my charges turned out to be dumb as Siberian felt boots.” - “Who is this?” - you ask. - “For example, tiny Octopus bocki.” - “Why are they so undeveloped?” “Most likely, because they don’t have to deal with difficult situations in life.”
David Liittschwager, photographed at Queensland Sustainable Sealife, Australia Callistoctopus alpheus is propelled forward by a jet of water released by the muscles of the mantle through a funnel located just below the eye.
It doesn't matter whether octopuses are smart or stupid, whether they think about food or think in spiritual categories - in any case, there is something special about them. Something bewitching and alluring. ...One more dive left. It's sunset time on Lembeh Island. You stopped at the bottom of a rocky slope. A couple of fish are swimming in front of you, they are spawning. Not far from them, an eel curled up in a hole. A large hermit crab slowly drags its shell, and it thumps dully on the bottom. A small octopus is hiding on a rock. You decided to take a closer look at him: he begins to move slowly, hovering for a moment in the water column, like an eight-armed yogi. Then he goes about his business again. Now he has already climbed over the rock, but you still couldn’t see exactly how he was moving - either he was pulling himself up with his front tentacles, or he was pushing himself off with his back ones. Continuing its movement, the mollusk finds a small crevice and instantly disappears there. Well, he left. No, not really: a tentacle sticks out from the crack and checks the space surrounding the hole, grabs a few pebbles and seals the entrance with them. Now you can sleep peacefully.
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. The female emperor penguin “stands” in the midst of 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, incubates eggs for 12-14 months. 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 supply of nutrients in the liver (like a bird before migrating) and uses it up 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 all the rest have large and very large eggs, direct development (from the eggs young hatch 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?
Z. von Boletsky tried to calculate the duration of incubation of cephalopods in cold waters. He extrapolated to the side low temperatures graph of incubation time versus temperature for inhabitants of temperate waters. 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, on the coast of the Aleutian Islands would do this for a year and a half, and the sand octopus off Hokkaido, at a depth of 50-70 m, would do this for 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 other than octopuses, no other cephalopods laid eggs are not protected (they are not even buried 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 Indian and western 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 Pacific (R. pasifica) and northern Russian (R. palpebrosa, R. moelleri) eggs at a temperature of 0-2°C is 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.
Smart sea chameleons 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 recent years, various myths and fables about octopuses as “monsters” have given way to true stories from 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, they know that 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 coloring 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.