What is the crab's habitat? King Leopard Crab (Parathelphusa Pantherina)

For those who saw Kamchatka crabs for the first time in their lives, these animals make a great impression.

Kamchatka crab in size - distinguished representative not only decapods, but also all crustaceans. Characteristics The structures of crustaceans, reproduced in the Kamchatka crab on a large scale, are strikingly striking even with the most superficial glance at this animal.

The width of the shell of the average male Kamchatka crab is about 16 centimeters, the span of its legs is almost 1 meter, and its weight exceeds 2 kilograms. The largest specimens reach 25 centimeters in carapace width, one and a half meters in leg span and 7 kilograms in weight.

The body of the Kamchatka crab consists of a cephalothorax, covered with a common shell, and a belly, folded under the cephalothorax. Therefore, if you look at a crab from above, only its shell and legs are visible. A powerful shell with large sharp spikes reliably protects the animal and, in addition, serves as a support for the muscles. The shell, like that of the crayfish, fuses with the body only on the back, and on the sides it lags behind the walls of the body and hangs down like the sides of a jacket, covering the gills. The gills in the resulting cavities are protected from damage and at the same time are easily washed with water. At the front, two pairs of antennae, eyes on stalks, jaws and legs are attached to the cephalothorax. Leading edge The shell is armed with a sharp outgrowth that protects the eyes.

The abdomen of the crab, always tucked under the cephalothorax, in females bears special appendages for bearing eggs. The abdomen contains the intestine and internal genital organs. The first pair of crab legs are armed with powerful claws, the next three pairs are used for movement, and last pair reduced legs are always located under the shell and are used to clean the gills. The muscles of the walking legs are very well developed.

What do Kamchatka crabs eat?

Kamchatka crabs are predators. They eat marine bottom polychaetes, mollusks, amphipods, echinoderms, small sea acorns and other bottom animals. The crabs tear their prey with their claws and, using their legs and jaws, crush, grind and send it into their mouths. The right - large - claw is used to crush shells of mollusks and skeletons sea urchins. With its left claw, the crab can tear only soft prey. Very interesting experiments were carried out to find out what sense guides crabs in search of prey. Food was lowered into a large aquarium where Kamchatka crabs were kept. The animal immediately reacted to the smell characteristic movements antennas and began searching for prey. The crab cannot determine the direction to the prey by smell, so it begins to move slowly, feeling the bottom with the ends of its claws. The crab lowers its claws vertically downwards and, touching the ground with the ends of its claws, quickly opens and closes them, as if snapping scissors, to see if anything gets caught. These probing movements are very energetic and "nervous".

The crab searches blindly, describing the most incredible loops along the bottom of the pool. As it approaches the feeder, when the smell of food intensifies, the crab becomes very excited and probes the bottom with its claws even more often. However, even in close proximity to the food (for example, at a distance of 1 centimeter from the end of the claws to the food), the crab repeatedly misses and moves away from it again. This suggests that the crab's sense of smell and vision are poor helpers, and it finds its prey only through touch.

Finally, the crab probes for food with the tip of its claw and quickly grabs it with one claw or both at once. In search of prey, the animals lost an unusually large amount of time, traveling an unnecessary long distance.

Kamchatka crabs spend their entire long lives wandering, repeating the same route every year. The Kamchatka crab is an exclusively running animal and is completely unsuited to either swimming or burrowing into the ground. The crab cannot burrow, because then its open gills can become clogged with silt. Powerfully developed leg muscles allow you to cover long distances. The crab runs both forward and sideways, alternately throwing out and bending its walking legs. The claws of the feet act like pegs stuck into the ground. The body is supported by weight when walking. The speed of movement of Kamchatka crabs in a straight line reaches 2 kilometers per hour. However, the crab usually moves in zigzags, and the distance it travels per day does not exceed 10-13 kilometers. Individual crabs wander in different directions, and the speed of movement of the entire school is only 2-4 kilometers per day. Crab schools all year round walk within their migratory area. The size of such areas for one school is almost 200 kilometers. Some crabs stray from their schools and move into schools in neighboring areas. The reason for such transitions is strong competition for food. Animals often move to areas where fishing is more active. There, the number of crabs drops significantly due to fishing, and competition for food decreases.

Where do Kamchatka crabs winter?

The wintering grounds of crabs are located quite far from the coast at depths of 110 to 200 meters. In fact, the crab does not hibernate, but continues to lead the same active lifestyle in winter as in summer. The departure to depth is explained more low temperatures water in shallow waters and ice formation. In the spring, when the bays of the sea are cleared of ice, the crabs move to shallower areas. During this period, males and females of the king crab stay in separate herds and move to the shore in parallel paths. Female crabs carry eggs on their abdominal legs, which have been developing since last year, and halfway through the adult crabs' journey to the shore, a mass hatching of larvae occurs. The fully developed crab embryos in the eggs, whose translucent eyes gave them the name “caviar with eyes,” tear the shells of the eggs into two halves and float up into the water column.

Reproduction of Kamchatka crabs

About a month after the start of migration, schools of males and females meet in shallow waters and mix. The mating period begins. The females at this time look very unpresentable: a dirty shell overgrown with barnacle shells, empty egg shells on the abdominal legs. Nevertheless, the males choose their mates and clamp the claws of the females with their claws. Couples can remain in this “handshake” position for 3 to 7 days. Then the males help the females moult by pulling off the contaminated old shell from them, and attach spermatophores to the bases of the third pair of walking legs of the female. After this, the partners separate. After some time, the female lays eggs on her abdominal legs, which are fertilized from the spermatophore and which the female carries on herself until next spring.

After mating, the schools of females and males again migrate separately, now the crabs go in search of food and feed all summer. Before the summer migration, the males molt, but in complete solitude, hiding among the underwater rocks. During the feeding period, crab schools gradually move from one field to another with average speed about 4 kilometers per day, destroying a significant number of bottom animals.

Where do Kamchatka crabs live?

The largest quantity of Kamchatka crab, as its name suggests, is found off the coast of Kamchatka, as well as in Primorye. Its distribution area goes from Posyet Bay through the northern part Sea of Japan, through the Sea of Okhotsk and most of the Bering Sea along the Aleutian Islands to the Pacific coast of Canada.

After the introduction of a food embargo in 2014 on agricultural products, raw materials and food from countries that applied economic sanctions against Russia, there is a shortage of many products on the market. European cheeses, fruits, fresh berries and seafood have disappeared from restaurant menus. Many establishments had to not only look for alternative suppliers, but also completely change their concept. As a result, over the past few years, restaurants have appeared in Moscow, the menu of which contains mainly Russian ingredients, primarily meat: “Voronezh”, “Ryba Net”, “Yuzhane” and many others. Russian fish and seafood also began to be in demand, and crabs replaced lobsters. To find out all about the latter, The Village spoke with the chef of the Erwin restaurant. RiverSeaOcean" by Alexey Pavlov and compiled a detailed guide to these crustaceans.

What kind of crabs are served in Moscow restaurants?

There are many varieties of crabs, but restaurants usually use only five to seven types, since other crustaceans have little meat. The most popular crab is Kamchatka crab. Other types are most often served to attract guests. Crabs differ among themselves in habitat and seasonality - these factors affect the appearance of the crustacean, its filling with meat and taste.

Kamchatka crab

Weight: from 3 to 7 kilograms

Catch: from September to April

Peculiarity: large size, caviar

Price: 10 thousand rubles for a live crab

It is also called royal, because among crustaceans Far East he is the largest. Kamchatka crab began to be bred in the Barents Sea in the mid-20th century, from where it is now caught and delivered to restaurants around the world. Kamchatka crab meat consists of dense and thick spaghetti-like fibers and usually has a sweetish taste. Although some crabs of this species may be salted, this depends on the sea in which the crustacean lived.

One of the features of this species is caviar. It is the size of a grape and has a light purple color when raw. Sometimes it occurs when ordering a whole crab. No one extracts caviar separately: it is expensive and illegal.

spiny crab

Weight: from 800 grams to 1.8 kilograms

Catch: cannot be caught during the molting period (mid-summer)

Peculiarity: spines all over the shell

Price: 6 thousand rubles for a live crab

The shell of this crab is covered with sharp spines from the head to the claws - hence the name. Despite its small size, the spiny crab is not inferior to the Kamchatka crab in terms of meat content. It tastes just as juicy and sweet, although it has less fiber than king crab. The “thorn” is brought to Moscow from the southern part of the Bering, Okhotsk and Japanese seas.

Hairy crab

Weight: from 900 grams to 2 kilograms

Catch: from August to October

Peculiarity: unusual meat structure, liver

Price: 400 rubles per 100 grams

Hairy crab is being brought to Moscow from coastal waters Sakhalin. Hair crab is filled with meat and is fully used in cooking, just like king crab and spiny crab. This crab has a short season - only three months, but even during this time it contains a lot of meat. It has a rather specific taste, as it consists of very thin fibers, similar to threads.

The main value of the hairworm is the liver. It has the same positive effect on the human body as, for example, oysters. The hairworm's liver is small, about the size of a teaspoon, gray and tastes like a delicate dessert with sourness. However, the liver is not found in all hairworms.

frog crab

Weight: from 200 to 400 grams

Catch: throughout the year

Peculiarity: appearance

Price: 200 rubles per 100 grams

The crab got its name because of its resemblance to a frog: it has a large shell and small claws on top and bottom. There is little meat in the “frog” - only in the back of the crab, like crayfish. Its structure resembles pulp, and its taste is similar to fish such as sea bass or sea bream.

Frog crab is caught in Indian Ocean not far from Seychelles and delivered to Russia in boiled and frozen form. Some restaurants may serve the whole frog to make the dish interesting. But due to the strong shell, it is not easy to get to the meat, so it is better to ask to fillet the crab and process it.

Blue crab

Weight: from 400 to 500 grams

Catch: throughout the year

Peculiarity: the most tender meat

Price: 300 rubles per 100 grams

Blue crab lives on Atlantic coast Northern and South America, as well as in the Baltic, Mediterranean, Adriatic and North Seas. This crustacean has the softest and most tender meat due to the lack of fiber in it. But poor fillability - only 40% of the meat total mass bodies. Therefore, blue crab is usually used as an additional ingredient rather than as a main dish.

Snow crab

Weight: from 200 to 400 grams

Catch: from October to April

Peculiarity: looks like a spider

Price: 300 rubles per 100 grams

Snow crab is also called opilio. It is supplied to Moscow from Murmansk. Restaurants most often offer its phalanges - long (about 30 centimeters) and thin, like pencils, with a small amount sweetish meat, which is not very easy to get. Also used in cooking are the claws and “fists” of this crab. Opilio is dense, juicy and rich in vitamins meat.

How are crabs caught and prepared?

All crabs are caught, in principle, the same way - it’s just that some do it legally, and some don’t. Restaurants deliver crabs live, as well as fresh frozen and boiled-frozen. Live crabs are transported by plane in special containers with small briquettes that cool the container. After transportation, the crab is allowed to rest in its natural environment, otherwise it will die, and only then is it delivered to restaurants.

Live crabs can only be found during the season, since the rest of the time the crustaceans go to the bottom and feed from the resources of their own body - they cannot be caught. To cook crabs throughout the year, restaurants buy them fresh frozen or boiled-frozen. The taste of this meat is no different from freshly cooked meat.

Crabs can be prepared in different ways, it all depends on the imagination of the cook. But most often they are simply boiled or steamed, slightly processed olive oil, herbs and serve. Cooking time depends on the weight of the crab, but on average 30 minutes.

What do you eat crabs with?

Most often, crabs are served with hot melted butter, to which garlic and finely chopped herbs (for example, wild garlic) are added if desired. Among the sauces, the best is a simple aioli based on homemade mayonnaise. Some people like to eat crab with tartar, wasabi mayonnaise and other bright-tasting sauces, but they can overpower the taste of the meat. As for dishes with crab, it is better to combine it with simple products - cereals, spaghetti, bread. Classic dishes with crab include risotto, fettuccine, and bruschetta. Rose wine also goes well with crabs.

In the places where crabs are brought from, they are considered quite regular product. Some people specifically travel, for example, to Murmansk to try crab meat. But if we talk about large enterprises involved in growing these crustaceans, they do not sell anything to the locals, preferring to give all the goods to wholesalers, especially abroad.

How to eat crabs correctly?

Most easy way To cut a crab is to ask the cook to serve it to you open. If you want to do everything yourself, then you should pick up scissors and start, for example, with the phalanx. The phalanx must be cut at the root and cut across to the very end on both sides. After which you need to remove the top cover and remove the meat with a special device that looks like a spatula with a clove. The claw attachment has three threads that hold everything together, so you have to pull the meat onto the plate from them.

To get the meat out of the “fist”, you just need to break it with a special hammer. The meat in the “fists” differs from the meat in the phalanges in its denser structure. As for the crab head, there is practically no meat in it. But if you wish, you can open it too. To do this, cut the crab with scissors starting from either side. Crabs only have a hard shell, and the bottom is soft, so it can be cut through without difficulty.

At least once in their life everyone has had the opportunity to try this amazing and useful seafood delicacy with a delicate pleasant taste - crab meat. We are not talking about a popular substitute - the so-called “ crab sticks", made from fish protein and dyes, and about natural product- meat of sea animals. There is a world large number all kinds of crabs, many of which reach very significant sizes - up to three and a half meters, and can weigh up to three kilograms.

For consumption, the tender white crab meat contained in its claws and paws is used. The meat is pre-boiled and then frozen or canned. Crab meat is considered a dietary product.

Composition of crab meat:
Crab meat contains many useful substances, including vitamins A and group B (B1, B2, B5, B6, B9 and B12), micro- and macroelements such as iron, potassium, calcium, iodine, copper, phosphorus, selenium and other minerals. IN crab meat contains fatty acids such as Omega-3 and Omega-6. Crab meat contains essential amino acids.

Calorie content of crab meat:
The calorie content of crab meat is about 90 kcal per 100 grams of product.

Useful properties of crab meat

Crab meat has a positive effect on work cardiovascular system, strengthens the heart muscle, normalizes cholesterol levels in the blood, reduces the likelihood of vascular and heart diseases.
It has a beneficial effect on the thyroid gland and the functioning of the endocrine system.
Crab meat is good for the digestive system.
Helps improve vision.
Helps fight stress and depression, improves mood, strengthens the nervous system.
Experts recommend including crab meat in the diet of overweight people.
Crab meat helps protect the body from premature aging.
Positively affects the condition of the skin.
Crab meat is considered an aphrodisiac and helps increase potency in men.

From a zoological point of view, crabs are the same crayfish, only with short tails. Their small head is hidden in a special recess under the edge of the shell. In terms of the shape of their body, all crabs differ sharply from the rest of their crustacean relatives. The fact is that in adult individuals the abdomen is shortened and bent down, and if you look at this creature from above, you can only notice its rounded cephalothorax. Like all other representatives of the fauna world, these creatures have their own hierarchy, which is headed by the so-called king crab.

King among crabs

The second name for king crab is Kamchatka. This is one of the largest crustacean animals inhabiting the reservoirs of the Far East. Tasty, tender and nutritious meat has made Kamchatka crab an object of constant fishing, including illegal fishing. The history of the appearance of this creature in the waters Russian Federation is quite simple: in the middle of the last century, this species of crustacean was deliberately introduced into

The Kamchatka crab is a massive and powerful crustacean. Often the width of its shell reaches 26 cm, and in individuals inhabiting it in general it is 29 cm! The span of the walking limbs of this creature ranges from 1 to 1.5 meters, and its weight is up to 7 kg. The crab's claws are located on the first pair of walking legs, with the right claw slightly larger and stronger than the left. The animal needs it to break mussel shells, to destroy shells, etc. He needs the left claw to crush food. By the way, this crab feeds exclusively with the help of its left claw.

Where does the king crab live?

The habitat of this creature is very large and diverse. Kamchatka crab can be found in Okhotsk, Japan and Scientists who observed the life activity of these crustacean animals came to the conclusion that their greatest concentration is concentrated on the western coast of Kamchatka. It is there that the main crab fishing takes place year after year.

Reproduction of Kamchatka crabs

The king crab (photo presented in the article) reaches sexual maturity by 8-10 years, if, of course, we're talking about about males. Females become sexually mature a little earlier. These creatures can be called real travelers: from year to year they repeat the same seasonal route. They while away the winter cold underwater at a depth of 250 m, spending almost the entire winter there. With the onset of spring, crabs return to their native coast for molting and subsequent reproduction. When autumn comes, they go deeper again. And so on all the time.

It is estimated that one female king crab can lay up to 300 thousand eggs during the breeding season! Like all crayfish, the females of these crabs carry eggs on their abdominal legs throughout the year. The nature of the wanderings of these creatures largely depends on fluctuations in water temperature. From their permanent wintering places, they move to the shores in whole schools: during this period, hundreds of thousands of long-legged king crabs move along the bottom of the sea. The spectacle is, of course, amazing!

It is worth noting that during this period, females carry almost fully formed larvae. On the way to the treasured shallow water, the latter hatch from their eggs and begin to swim independently in the water column. Their mothers, meanwhile, continue on their way. Unfortunately, many larvae do not live to reach adulthood, since they are the favorite prey of various

In general, Kamchatka crabs are slow-growing creatures, and water temperature is decisive here. For example, in warm waters American coasts they are growing and developing twice as fast.

Kamchatka crab is a valuable fishery object

The natural lifespan of king crabs is 20 years, but many of them are not destined to live that long. And all because of the constant hunting for them by humans: king crab is a valuable commercial product that is in demand all over the world! When catching them, preference is given to males with a shell length of more than 13 cm. Females are usually not caught.

Crab claws are a delicious delicacy. Its right claw, which contains the most tender and nutritious meat, is especially valuable and tasty. By the way, the meat of this crab is rich in all the necessary vitamins, amino acids and minerals: zinc, protein, iodine and other substances provide invaluable benefits to our body. The shells and entrails of these creatures are processed into useful fertilizer.

Beware, poachers!

The uniqueness of king crabs and the high demand for them from consumers have provoked illegal fishing of these animals. Poachers are not asleep: there are many crabs of dubious quality on the domestic market. This is poached products.

Mostly “illegal” crabs come to us from Barents Sea, and the catch of Far Eastern poachers almost never reaches the European part of our country. All this leads to the fact that crustaceans are massively exported to Japan. Rospotrebnadzor employees do not recommend eating such products, because only God knows what quality the king crab is.

The price of the meat of these animals corresponds to its quality. For example, a kilogram of a Kamchatka crab knee will cost about 1,300 rubles, and a kilogram of the second phalanx will cost about 1,700 rubles. For a whole crab, say, weighing 5 kg, you will have to pay about 10,000 rubles. Here it is expensive pleasure! And it’s no coincidence.

As mentioned above, Kamchatka crab meat is an irreplaceable source of all the microelements, vitamins and, of course, minerals that our body needs. Doctors recommend eating as many dishes prepared from this animal as possible. This helps to increase visual acuity, improve the body’s condition in case of cardiovascular diseases and anemia.

Crabs are a large group of aquatic and semi-aquatic animals belonging to the order Decapod Crustaceans. Crabs differ from related crayfish, shrimp, lobsters and lobsters by a noticeably shortened abdomen, tucked under a wide cephalothorax. This gives them a specific, well-recognized shape. At the same time, crabs have reached unprecedented diversity: 6,793 species of these animals are united in 93 families, which is half the number of the entire order.

The spotted-footed rock crab (Grapsus grapsus) is a native of the Galapagos Islands.

Along with a special body shape, crabs are characterized by the presence of 10 pairs of limbs. They are divided into thoracic and abdominal. The first 3 pairs of thoracic limbs are very short, they are called maxillae because they do not participate in movement, but only serve to bring food to the mouth. The remaining pairs of thoracic legs are used for locomotion, grasping and cutting food, and can also perform other auxiliary functions. The pair of the largest and most massive legs are claws. With their help, crabs can not only hunt, but also defend themselves and participate in mating fights. The narrow specialization of these organs affected their appearance: often the right and left claws have different size and shape, giving the crab's body a noticeable asymmetry. As for the abdominal legs, they are small and are used for fertilization (in males) or bearing eggs (in females). Vital organs such as gills are connected to the chest legs of crabs. Often their petals are located directly on the leg segments or near the place of their attachment to the body.

Due to the huge difference in the size of the claws, lure crabs appear to be one-armed. Like people, these animals are right-handed and left-handed, with 85% being right-handed.

Crabs are one of the most advanced crustaceans, so they have developed sensory organs. Vision plays a big role in their lives. The eyes of these animals are complex, faceted. They are made up of thousands of eyes, each of which sees only a tiny part of the space directly in front of them. The final assembly of the image occurs in the animal’s brain. Numerous observations have proven that with the help of vision, crabs identify a potential enemy, find a partner during the breeding season, and navigate in search of food. But if an animal is blinded, it will only lose the ability to see danger, but will find food and a partner with almost the same efficiency. Antennas (“antennae”), capable of capturing odors, will help him with this. If the crab's antennae are also cut off, then it... will find food again. True, in this case he will have to spend a lot of time and effort, because he will literally move towards the prey by touch, tapping his claws on the ground. Some types of crabs have balance organs - statoliths. By the way, the eyestalks play a huge role in their physiology. These are real endocrine glands, capable of secreting hormones and regulating such body functions as the frequency of molting, the onset of puberty, and even color changes!

The Latreille's land bigeye (Macrophthalmus latreillei) has especially long eye stalks, which is associated with the need to inspect the area at a great distance.

Crabs do not have skin as such; it is replaced by a layer of hard and impenetrable chitin, which forms a kind of shell. Chitin is unable to stretch, making normal linear growth impossible. Crabs solve this problem by molting regularly. When the old shell bursts, a soft and defenseless animal emerges. It takes from several weeks to six months for the new cover to harden; during this period, the crab hides in a secluded place and grows intensively. Chitin can be impregnated with all kinds of pigments, so crabs can have almost any color.

The bicolor vampire crab (Geosesarma bicolor) gets its name from its unusual combination of bright yellow eyes with a dark purple shell. Due to its impressive appearance, it is often kept by amateur aquarists.

In addition, the chitinous cover may have outgrowths: sparse and hard, like spines, short and hard, like bristles, or long and thin, like wool.

The Chinese mitten crab (Eriocheir sinensis) stands out among its relatives with a “fur” muff on its claws.

The sizes of these animals also vary widely. The diameter of the shell of the world's smallest pea crab does not exceed 1 cm, while the leg span of the largest Japanese spider crab reaches 4 m and weighs 20 kg.

Pea crab (Pinnotheres boninensis) lives on the coast of the Azov and Black Seas.

Crabs inhabit all the seas and oceans of the planet, but they reach their greatest diversity in the tropics. The habitat of these crustaceans has a very wide range: crabs can be found in the shallow waters of seas and oceans, among thickets of corals on reefs, at depths of up to 5000 m, in cave ponds, in the intertidal zone, mangroves and even in the depths of islands far from the coast. The vast majority of them live in salt water, about 850 species live in fresh water. Crabs, long time Those that live on land store water under their shells or develop organs like lungs. Their underdeveloped gills almost do not work, and when constantly immersed in water, such individuals die. Bottom-dwelling species are often active in the dark, land crabs most active during the day.

The second largest Tasmanian giant crab on the planet (Pseudocarcinus gigas), with a carapace width of 46 cm, weighs up to 13 kg.

When moving, these crustaceans never place both legs of one pair on the ground at the same time, which gives their gait stability, but the short body length and large number of legs make forward movement inconvenient, so crabs prefer to walk sideways. At the same time, this does not in the least prevent them from developing decent speed, for example, a grass crab covers 1 m in 1 second! But these animals swim poorly and reluctantly.

The exception is swimming crabs, whose back pair of legs are transformed into paddle-blades, thanks to which they feel in water element like home.

These crustaceans have a quarrelsome character; they all live alone and jealously guard their areas or shelters; Males are especially aggressive. At the same time, areas of small crabs are very small, so there can be up to 50 burrows per 1 sq.m. Danger is the only thing that makes the inhabitants of the colony forget about strife. When threatened, crabs signal their neighbors by waving their claws, making sounds, or tapping on the ground. Thanks to vibrations, even those individuals that do not see the enemy manage to hide.

Blue soldier crabs (Dotilla myctiroides) form large aggregations on beaches.

Shelters deserve special attention. In the simplest case, these animals hide among coral branches, in crevices between stones or shell valves, and in the cavities of sponges. But many crabs do not expect favors from nature, but instead dig holes in viscous silt or sand. These houses may have one straight passage (often quite deep), or several branched passages with emergency exits; beckoning crabs equip the entrance to the hole with a lid. Some species live under the canopy of jellyfish, among the tentacles of sea anemones, in the mantle cavity of mollusks, among the spines, or even in the rectum of sea urchins.

These holes on one of the beaches of Malaysia were dug by the closest relatives of soldier crabs - scopimera. Each individual, pushing sand out of its home, rolls it into a neat ball. The crab droppings have the same shape when they eat the soil.

Crabs have practically no food specialization; they are all omnivores to one degree or another. These animals can eat the bacterial film covering stones, algae, fallen leaves and flowers, bivalves, polychaete worms, starfish, small crustaceans and even octopuses. Like crayfish, crabs readily feast on carrion. Species living in shallow water happily “snack” the soil on regular food. By passing sludge through their intestines, they assimilate the microorganisms contained in it. Crabs not only grab large prey, but cut it up like real gourmets. At the same time, they use their claws like a knife and fork: they hold the prey with one, and cut off neat pieces with the other.

A grass crab (Carcinus maenas) is about to dine on a bivalve.

Reproduction in crabs has a pronounced seasonal character; different types it is dedicated to one or another natural phenomena(rainy season, highest tides). For example, Christmas Island red crabs (Gecarcoidea natalis) live on land away from the shore, but move to the surf line to lay eggs. Their migration is one of the most ambitious phenomena in nature.

Millions of individuals rush towards their goal like a living river, overcoming roads, ditches and other obstacles along the way.

At this time, crabs die en masse under the wheels of vehicles and under the feet of people who are tired of avoiding countless travelers.

To prevent the crabs from dying, Christmas Island is creating barriers along roads to divert migrants away from dangerous routes.

Pay attention to the insects in the frame. These are yellow crazy ants brought to the island by people. They turned out to be a very aggressive and prolific species and have already destroyed 1/3 of the crab population - 20 million individuals!

No less interesting are the mating battles of beckoning crabs. With their hypertrophied signal claw, they threaten their opponents and even fencing with it in a collision. Then they signal the female with waving movements, as if declaring their victory. Such emphasized ritualism has led to the fact that in many species there is a very noticeable difference between males and females (sexual dimorphism).

A duel of beckoning crabs.

Before mating, the couple sometimes takes a “face to face” position and can remain in this position for several days. Interestingly, one mating is enough for a female to lay fertilized eggs throughout her life. This is explained by the fact that the male presents her with sperm packed in special bags - spermatophores. In them, germ cells remain viable for many years During the next season, the female dissolves the spermatophore membrane with special secretions and fertilization occurs again. The fertility of crabs is very high and amounts to tens of thousands and millions of eggs. The female carries them on her abdominal legs from a couple of weeks to several months. The hatched larvae begin to swim freely.

Swimming crab larva.

After several molts, they turn into young crabs, which settle in the biotopes characteristic of a particular species. The lifespan of these crustaceans ranges from 3-7 years for small species to 50-70 years for the huge spider crab.

Japanese spider crab (Macrocheira kaempferi).

Due to their great diversity and abundance, crabs have many enemies. Their lives are encroached upon by fish, octopuses, crocodiles, starfish, seagulls and practically everything beasts of prey wandering onto the coast. Crayfish raccoons generally specialize in collecting crabs on the shore. Such intense interest on the part of carnivores has forced these crustaceans to develop many methods of defense. The simplest of them is camouflage. This is achieved in some cases by coloring, which very accurately reproduces the color and even the pattern of the substrate on which the species is found.

The caramel crab (Hoplophrys oatesii) imitates the dendronephthia coral on which it lives in color and shape.

In other cases, surrounding objects are used for cover. For example, shy crabs cover themselves with a shell-shield, decorator crabs cut out pieces of bryozoans and hydroids with their claws and place them on their backs, gluing them together with special secretions. On the crab's back, these colonial animals continue to develop and transform its shell into a flower bed.

It is difficult to recognize the perfectly camouflaged decorator crab (Camposcia retusa) in this crawling bush.

The Dromia crab looks for a sponge and, like a real seamstress, cuts a piece out of it exactly to the size of its back.

The Dromia erythropus crab resembles an old woman in a beret. Since its body is quite fleshy, the dromia has to look for a flap with a curve that perfectly follows the convexities of its shell.

If disguise does not help, active methods of defense are used. Large crabs take a fighting stance and raise their claws up. If the offender does not understand the hint, they use their wire cutters and are capable of inflicting deep cuts. Boxer crabs always hold sea anemones in their claws, the stinging cells of which are dangerous even for relatively large animals.

A female boxer crab (Lybia tessellata) in a fighting stance with sea anemones. A clutch of eggs is visible on the abdomen of this individual.

Many species are capable of autotomy (self-amputation). When it sees an enemy, the crab throws its leg away by contracting special muscles. In this case, the valves at the tear site immediately close the wound and stop the bleeding. If such a handout was not enough, the victim offers the predator the next limb. Severed legs grow back after several molts.