Various types of crabs. Land hermit crab - a crab that can drown in water How small crabs develop
Seeing this amazing arthropod, any faint of heart will shudder with horror and surprise - after all, there is no one in the world more interesting and, at the same time, more terrible than a coconut crab. In any case, among arthropods - after all, he is rightfully considered their largest representative.
1. The coconut crab has many other "names": for example, the thief crab or the palm thief - after all, this strange arthropod really steals its prey. Travelers of past centuries, who visited the islands spread in the West Pacific Ocean and in the Indian Ocean, talk about the fact that the coconut crab hides from prying eyes in the dense greenery of palm trees in order to suddenly grab its prey lying right under a tree or nearby From him.
2. Coconut crab (lat. Birgus latro) is actually not a crab at all, despite its striking resemblance to the arthropod relative mentioned in the name. This is a land hermit crab belonging to the species of decapods.
Strictly speaking, it is also a stretch to call a palm thief a land arthropod, since part of its life passes in the sea, and even tiny crustaceans are born in the water column. Newborn babies with a defenseless soft abdominal cavity are busily crawling along the bottom of the reservoir in search of a reliable house, which can serve as a nut shell, and an empty shell of a mollusk.
3. In "childhood" birgus latro is not too different from a hermit crab: he drags his shell along with him and spends almost all the time in the water. But having once left the larval state and left the water, he is no longer able to return there, and at some point even carry a shell-house behind him. Unlike the abdomens of hermit crabs, its abdomen is not an Achilles' heel and gradually hardens, and the tail curls under the body, protecting the body from cuts. Thanks to special lungs, he begins to breathe out of the water.
In truth, most of the legends noted this particular feature of it - the first Europeans who arrived on the islands described coconut crabs as creatures hiding in the foliage of trees with long claws that suddenly stretched to the very ground and captured prey, up to sheep and goats. Scientists have confirmed that birgus latro has great strength and can lift up to 30 kg of weight. However, they found out that the crab uses its abilities to drag cargo from place to place, preferring to eat dead animals, crabs and fallen fruit.
4. How do crayfish manage to exist equally comfortably both in water and on land? It turns out that wise nature provided them with two breathing instruments at once: lungs, ventilated by air on the surface of the earth, and gills, allowing them to breathe underwater. But over time, the second organ loses its functions, and palm thieves have to completely switch to a terrestrial lifestyle.
5. Those wishing to meet such a miracle would have to go to the tropics - coconut crabs are found on the islands of the Indian Ocean and on some western Pacific islands. It is not easy to see them in the daylight: palm thieves are nocturnal, and in sunny time they hide in rock crevices or in sandy burrows lined with coconut fibers - this helps to maintain the required level of humidity in the home.
6. And although the version that the crayfish is able to crack a coconut with its front claws failed miserably, its limbs, nevertheless, are sufficiently developed to quickly climb a palm tree trunk or bite off a person’s finger phalanx. And cancer is really not indifferent to coconuts: nutritious pulp is the main dish in its menu, to which it owes its “coconut” name.
7. Sometimes the diet of crayfish is enriched with the fruits of pandans, and according to some sources, palm thieves happen to eat their own kind. Hungry crayfish accurately finds the nearest "restaurant": an excellent sense of smell serves as an internal navigator, which brings it to the source of food, even if it is many kilometers away.
8. As for the "thieves' status" of cancer, this is due to its irrepressible desire to pull into its mink all sorts of things from the category of the one that lies badly - edible and not very much.
Coconut crab meat is not only among the delicacies, but also belongs to aphrodisiacs, so these arthropods are actively hunted. In order to prevent their complete extinction, some countries have established severe restrictions on the capture of coconut crabs.
9. The body of the coconut crab, like all decapods, is divided into the front part (cephalothorax), on which there are 10 legs, and the stomach. The front, largest pair of legs has large claws (claws), and the left claw is much larger than the right one. The next two pairs, like those of other hermits, are large, powerful with sharp ends, used by coconut crabs to travel along vertical or inclined surfaces. The fourth pair of legs is much smaller than the first three, which allows young coconut crabs to settle in shells of mollusks or coconut shells, to protect themselves. Adults use this pair for walking and climbing. The last, very small pair, which is usually hidden inside the shell, is used by females to care for eggs, and by males for mating.
10. With the exception of the larval stage, coconut crabs cannot swim, and they will certainly drown if they stay in the water for more than an hour. For breathing, they use a special organ called gill lungs. This organ can be interpreted as a developmental stage between the gills and lungs, and is one of the most important adaptations of the coconut crab to its environment. Gill lungs contain tissues similar to those found in gills, but are suitable for absorbing oxygen from the air rather than water.
11. The coconut crab has a highly developed sense of smell, which it uses to find food. Like most water crabs, they have specialized organs located on their antennae that determine the concentration and direction of scent.
12. During the day, these arthropods sit in burrows or rock crevices, which are lined with coconut fibers or foliage to increase the humidity in the dwelling. While resting in its burrow, the coconut crab closes the entrance with one claw to maintain a humid microclimate in the burrow, which is necessary for its respiratory organs.
13. As the name suggests, this crab feeds on coconuts, and is actually able to climb a coconut tree, up to 6 meters high, where it plucks coconuts with powerful claws if they are not yet available on the ground. If a fallen coconut does not split when it falls, the crab will gut it for a week or even two until it gets to the juicy pulp of the nut. If this dreary job bothers the crab, he lifts the coconut up the tree and throws it down in order to make his work easier. Descending back to the ground, they sometimes fall, but without damage to health they can endure a fall from a height of 4.5 meters. The coconut crab will not refuse other fruits, newborn turtles and carrion. They have also been seen catching and eating Polynesian rats.
14. Another name for it is the palm thief, he received for his love for everything shiny. If a spoon, fork, or other shiny object gets in the way of a crab, you can be sure that he will certainly try to drag it into his mink.
15. From the beginning of June to the end of August, the palm thieves begin the breeding season. The courtship process lasts long and tedious, but the mating itself takes place quite quickly. The female carries fertilized eggs for several months on the underside of the abdomen. When the eggs are ready to hatch, the female descends to the seashore at high tide and releases the larvae into the water. During the next three to four weeks, the larvae floating in the water go through several stages of development. After 25 - 30 days, already small crabs sink to the bottom, settle in the shells of gastropod mollusks, and prepare to migrate to the ground. At this time, babies sometimes visit land, and gradually losing the ability to breathe underwater, they finally move to the main habitat. Coconut crabs reach sexual maturity about five years after hatching, but do not reach their maximum size until they are 40 years old.
16. Palm thieves live in the tropics, on the islands of the Indian and Western Pacific Oceans. Christmas Island in the Indian Ocean has the highest population density of coconut crabs in the world.
17. Swedish and Australian scientists have confirmed the veracity of all the stories about coconut crabs. So, the inhabitants of the Pacific islands claimed that they could smell, for example, meat or ripe fruits a few kilometers away. And indeed, the special baits planted by the researchers immediately attracted the attention of thieving crabs, who nevertheless disdained the usual pieces of bread that ordinary crabs are greedy for.
18. The janitor function is, of course, not bad and useful, however, since the birgus latro creature is predominantly nocturnal and not very friendly, stumbling upon it, the locals are not particularly enthusiastic. The decrease in its numbers forced the local authorities to set a limit on the capture of birgus latro. In Papua New Guinea, it is forbidden to include it in restaurant menus, on the island of Saipan - to catch crabs with a shell less than 3.5 cm, and also from June to September, during the breeding season.
19. On the inner surface of the walls of the gill cavities, this terrestrial descendant of hermit crabs develop grape-shaped skin folds, in which numerous blood vessels branch. These are real lungs, allowing the use of oxygen from the air filling the gill cavities. The lungs are ventilated due to the movements of scaphognathite, as well as due to the ability of animals to raise and lower the carapace from time to time, for which special muscles serve.
It is remarkable that the gills are also preserved, although they are relatively small in size. The removal of the gills did not harm the breath in the least; on the other hand, the crayfish has completely lost the ability to breathe in water. Submerged in water, the palm thief died after 4 hours. Residual gills, apparently, do not function. The palm thief digs shallow holes in the soil, which he lines with coconut fibers. Charles Darwin relates that the natives on some islands select these fibers from the burrows of the palm thief, which they need in their simple economy. Sometimes the palm thief is content with natural shelters - crevices in rocks, cavities in drained coral reefs, but even in such cases, he uses plant material to line them, which retains high humidity in housing.
Names: land hermit crab, tropical land hermit crab, Caribbean hermit crab, tree crab .
Area: the hermit crab lives in the Caribbean Sea (Bahamas, Belize, Venezuela, the Virgin Islands, the West Indies and Florida), up to 880 m above sea level.
Description: there are seven varieties. The land hermit crab has five pairs of legs. The first pair is the claws. The left claw is for defense, while the right claw is for eating. When threatened by the left claw, the crab blocks the entrance to the shell. The second and third pair of legs are used for walking. The fourth and fifth pair of legs are very small and the hermit crab never sticks them out of its shell. Breathing takes place through the gills. The body is cylindrical, elongated, covered with hairs. The front part of the crab's body is covered with a hard shell, the abdominal part is softer. Two pairs of retractable antennae: a long pair is used for touch, a short pair for smell. Vision is good. Sex can be determined from a crab that is outside the shell. The male has hairs on the first segment of the last pair of legs and lacks appendages on the abdomen.
Color: the claws are purple (in most crabs), brown, lemon and red.
The size: up to 3 cm.
The weight: adult hermit crab weighs up to 110 grams.
Lifespan: in captivity up to 11 years.
Habitat: sandy shores of the Caribbean islands, 1.8-3.5 km from the water's edge. Can be found in coastal plants: trees and mangroves. The hermit crab avoids places with dense vegetation and swamps. Prefers water of low salinity.
Enemies: fish prey on the larvae.
Food/food: feeds at night. Omnivorous scavenger, eats even the fruits of cacti and fresh horse or cow droppings.
Behavior: nocturnal animal. Dislikes sun and heat. During the day it hides in shallow burrows, under leaves, stones and logs. With a long stay in the water - sinks. An adult hermit crab sheds every 12-18 months, young ones - several times a year. After molting, it passes into a new, larger shell. Peak activity occurs at 8:00 pm. At a temperature of 20 "C and below, activity decreases, at 18" C it hibernates.
Social structure: social animal - lives in large groups.
Reproduction: sex ratio: in crabs weighing less than 10 grams. - 4-25 females per male; weighing 20-50 gr. - 1-2 females for three males weighing more than 50 grams. - 3-4 males per female. For mating, males and females come out of their shells. One young female lays 800-1200 eggs, an adult - 40-50000. Freshly laid eggs are red-brown in color. Over the next month, they gradually turn gray or blue. Three weeks after mating, the female goes to shallow water. There, with her fifth pair of legs, she collects eggs and transfers them to wet stones, where they are washed away by waves into the sea.
Season/breeding period: August-October.
Puberty: in the second year of life.
Offspring: the larva goes through several stages of development: zoe, glaucotoe, young hermit crab. The larva undergoing metamorphosis settles to the bottom and later gets out on land. Zoe (zoea) - long, thin, with two large eyes, reaches a length of up to 3 mm. Feeds on plankton. Grows through a molt (3-4 molts). After 4-5 molts, the zoe passes into the stage of glaucotoe. Now the eyes of the larva are on the stalks. Two pairs of microscopic antennae appear. The first pair of legs turns into claws. At this stage, the larva is similar to the adult. The glaucotoe stage lasts about a month (at the end of the stage, the larva reaches a length of 5 mm). Before the end of this stage of development, young crabs begin to look for suitable shells. Crabs that come out of the sea without a shell usually die. Once on land, young crabs are predominantly nocturnal. During the day, they hide in various cracks, under logs, or burrow into the sand.
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The land hermit crab is a land crab that can drown if it stays in the water for a long time. It lives in the Caribbean Sea, it is also common in Venezuela, the Bahamas, Belize, India, Florida, the Virgin Islands. These crabs are also called tree crabs, tropical land hermit crabs, and Caribbean hermit crabs.
Description of the land hermit crab
There are 7 varieties of tropical land hermit crabs. These crabs reach a length of about 3 centimeters, the weight of an adult reaches 110 grams.
The body shape is cylindrical, elongated. The body is covered with small hairs. The front part of the body is protected by a hard shell, and the abdominal part is much softer.
Land hermit crabs have 5 pairs of legs. The first pair are pincers. With the help of the right claw, the crab eats, and the left one is used for protection, for example, it can close the entrance to the hole in time of danger. Most crabs have purple claws, but they can also be lemon, brown, or red. The second and third pair of crab legs are for walking. The last two pairs of legs are very small and sometimes do not protrude from the shell.
Caribbean hermit crabs breathe with gills. There are 2 pairs of retractable antennae: long antennae are used for touch, and short ones perform the function of smell. Land hermit crabs have good eyesight.
When the crab is outside the shell, its sex can be determined: the male has hairs on the last pair of legs, and there are no appendages on the abdominal cavity.
Lifestyle of land hermit crabs
Tree crabs are social animals that live in large groups. They lead a nocturnal lifestyle, their peak activity is observed at 20 o'clock. Land hermit crabs do not like high temperatures and the sun, so during the day they hide in small holes, under stones, logs, leaves, and the like.
Land hermit crabs live on the sandy shores of the Caribbean islands, at a distance of 1.8-3.5 kilometers from the water. They are found among coastal plants. They avoid swamps and places with dense vegetation. Hermit crabs prefer low salinity water.
If a tropical land crab is left in the water for a long time, it will drown. Adults molt every 12-18 months, while juveniles molt several times a year. After molting, the crab chooses a new, larger shell.
At temperatures below 20 degrees, the activity of land hermit crabs decreases, and at temperatures below 18 degrees, they hibernate. These crabs can make various sounds: chirping, crackling, croaking.
Tropical land hermit crabs feed at night. They are omnivorous scavengers. Also, their diet includes cactus fruits and even fresh litter of horses and cows. In captivity, they can live up to 11 years.
Reproduction of land hermit crabs
The breeding season for tree crabs is August-October. To mate, males and females have to leave their shells. Young females lay 800-1200 eggs, and adult females - 40-50000 eggs. The color of newly laid eggs is red-brown, within a month they turn blue or gray.
3 weeks after mating, the female goes to shallow water, her eggs are on the 5th leg, she collects them and transfers them to wet stones. The eggs are washed away by the waves into the water.
In the larvae of land hermit crabs, several stages of development are observed: zoe, then glaucotoe, after the young crab. During metamorphosis, the larva settles to the bottom, and then crawls out onto land.
Zoe is thin and long, its size reaches 3 millimeters. She has 2 large eyes. At this stage, the larva feeds on plankton. Zoe makes 3-4 molts, during which it grows.
After 4-5 molts, the larva passes into the stage of glaucotoe. At this stage, it develops very small antennae, eyes are located on stalks, and the first paws are transformed into claws. Glaucotoe looks like an adult crab. This stage lasts about a month, after which the larva grows to 5 millimeters.
Before the last stage, young crabs begin to look for a shell. If a crab comes out of the sea without a shell, it usually dies.
On land, young crabs are active mainly at night, and during the day they hide in various cracks and crevices.
These crabs are kept in horizontal type terrariums. The soil is partially flooded with water, but the water level must be very low, as land hermit crabs drown easily.
Crabs are a large group of aquatic and semi-aquatic animals belonging to the order Decapod Crustaceans. Crabs differ from their related crayfish, shrimp, lobsters and spiny lobsters by a noticeably shortened abdomen, tucked under a wide cephalothorax. This gives them a specific, well-recognized form. At the same time, crabs have reached an unprecedented diversity: 6793 species of these animals are united in 93 families, which is half the number of the entire detachment.
Spotted rock crab (Grapsus grapsus) is an inhabitant 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 chest and abdominal. The first 3 pairs of thoracic limbs are very short, they are called mandibles, because they do not participate in movement, but serve only to bring food to the mouth. The remaining pairs of pectoral legs serve to move, capture and cut food, and can also perform other auxiliary functions. The pair of largest and most massive legs are pincers. With their help, crabs can not only hunt, but also defend themselves, participate in mating battles. The narrow specialization of these organs is reflected in their appearance: often the right and left claws have different sizes and shapes, giving the crab body a noticeable asymmetry. As for the ventral legs, they are small and are used for fertilization (in males) or gestation (in females). Such vital organs as gills are connected with the pectoral legs of crabs. Often their petals are located directly on the segments of the legs or near the place of their attachment to the body.
Due to the huge difference in claw size, fiddler crabs appear to be one-armed. Like people, these animals are right-handed and left-handed, with right-handers making up 85%.
Crabs are one of the most perfect crustaceans, so they have developed sensory organs. Vision plays an important role in their lives. The eyes of these animals are complex, faceted. They consist of thousands of eyes, each of which sees only a tiny part of the space directly in front of it. The final assembly of the image takes place already in the brain of the animal. Numerous observations have shown 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 the animal is blinded, it will only lose the ability to see danger, and find food and a partner with almost the same efficiency. In this he will be helped by antennas ("antennae") that can capture odors. If the crab also cut off the antennae, 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 eye stalks play a huge role in their physiology. These are real endocrine glands that are able to secrete hormones and regulate body functions such as the frequency of molting, the onset of puberty and even color change!
The terrestrial bigeye Latreille (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 not able to stretch, which makes normal linear growth impossible. Crabs solve this problem with regular moults. When the old shell bursts, a soft and defenseless animal is selected from it. It takes from several weeks to six months to harden the new cover, during this period the crab hides in a secluded place and grows intensively. Chitin can be impregnated with all sorts of pigments, so the color of crabs can be almost any.
The Bicolor Vampire Crab (Geosesarma bicolor) gets its name from its unusual combination of bright yellow eyes with a deep purple shell. Due to its imposing appearance, it is often kept by amateur aquarists.
In addition, the chitinous cover may have outgrowths: rare and hard, like thorns, short and hard, like bristles, or long and thin, like wool.
Chinese mitten crab (Eriocheir sinensis) stands out among relatives with a "fur" muff on claws.
The sizes of these animals also vary widely. The diameter of the shell of the smallest pea crab in the world 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 the greatest diversity in the tropics. The habitat of these crustaceans has a very wide range: crabs can be found in the shallow waters of the seas and oceans, among coral thickets on reefs, at depths of up to 5000 m, in cave reservoirs, in the tidal zone, mangroves and even in the depths of islands away from the coast. The vast majority of them live in salt water, about 850 species live in fresh water. Crabs that spend a long time on land store water under their shells or develop lungs-like organs. Their underdeveloped gills almost do not work, and with constant immersion in water, such individuals die. Bottom-dwelling species are often active in the dark; land crabs are most active during the day.
The Tasmanian giant crab (Pseudocarcinus gigas), the second largest on the planet, weighs up to 13 kg with a shell width of 46 cm.
When moving, these crustaceans never put both legs of one pair on the ground at the same time, which makes their gait stable, but the short body length and a large number of legs make it inconvenient to move forward, so crabs prefer to walk sideways. At the same time, this does not in the least prevent them from developing a decent speed, for example, a grass crab overcomes 1 m in 1 s! But these animals swim poorly and reluctantly.
The exception is swimming crabs, in which the back pair of legs is transformed into paddles, thanks to which they feel at home in the water element.
The nature of these crustaceans is quarrelsome, they all live alone and jealously guard their sites or shelters; males are especially aggressive. At the same time, the areas of small crabs are very small, so there can be up to 50 of their minks per 1 sq.m. Danger is the only thing that makes the inhabitants of the colony forget about strife. In the event of a threat, crabs signal their neighbors by waving their claws, making sounds, or tapping on the ground. Thanks to vibrations, even those individuals who do not see the enemy have time to hide.
Blue soldier crabs (Dotilla myctiroides) form large concentrations on the beaches.
Shelters deserve special attention. In the simplest case, these animals hide among coral twigs, in crevices between stones or shell valves, and in sponge cavities. But many crabs do not expect favors from nature, but dig holes themselves in viscous silt or sand. These houses may have one straight passage (often quite deep), or several branched passages with emergency exits; alluring crabs equip the entrance to the hole with a lid. Some species settle under the dome of jellyfish, among the tentacles of sea anemones, in the mantle cavity of mollusks, among needles, or even in the rectum of sea urchins.
These minks on one of the beaches of Malaysia were dug by the closest relatives of soldier crabs - scopimers. Each individual, pushing sand out of the dwelling, rolls it into a neat ball. The droppings of crabs have the same shape when they eat soil.
Crabs have practically no food specialization, they are all omnivores to one degree or another. These animals can eat the bacterial film covering rocks, algae, fallen leaves and flowers, bivalves, polychaete worms, starfish, small crustaceans, and even octopuses. Like crayfish, crabs willingly feast on carrion. Species living in shallow water are happy to “bite” the usual food with soil. Passing sludge through their intestines, they assimilate the microorganisms contained in it. Crabs do not just grab large prey, but butcher it like real gourmets. At the same time, they use 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 mollusc.
Reproduction in crabs has a pronounced seasonal character, in different species it is timed to coincide with certain natural phenomena (rainy season, highest tides). For example, Christmas Island red crabs (Gecarcoidea natalis) live on land far from the coast, but move to the surf line to lay their eggs. Their migration is one of the most grandiose phenomena in nature.
Millions of individuals rush towards the 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 transport and the feet of people who are tired of bypassing countless travelers.
To prevent the death of crabs, barriers are being set up along roads on Christmas Island, directing migrants to bypass dangerous routes.
Notice 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 alluring crabs. With their hypertrophied signal claw, they threaten rivals and even fencing with it in a collision. Then, with waving movements, they give a signal to the female, as if announcing 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).
Duel of alluring crabs.
Before mating, the couple sometimes becomes in a "face to face" position and may remain in this position for several days. Interestingly, one mating is enough for a female to lay fertilized eggs all 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 fecundity of crabs is very high and amounts to tens of thousands and millions of eggs. The female bears them on ventral legs from a couple of weeks to several months. The hatched larvae are free-swimming.
Swimming crab larva.
After several molts, they turn into young crabs, which settle in biotopes characteristic of a particular species. The life expectancy of these crustaceans ranges from 3-7 years in small species to 50-70 years in a huge spider crab.
Japanese spider crab (Macrocheira kaempferi).
Due to the great diversity and abundance, crabs have many enemies. Fish, octopuses, crocodiles, starfish, gulls and almost all predatory animals that wander along the coast encroach on their lives. Raccoons-crayfish generally specialize in picking up crabs on the shore. Such intense interest from carnivores forced these crustaceans to create a variety of ways to protect themselves. The simplest of them is disguise. It is achieved in some cases by coloring, which very accurately reproduces the color and even the pattern of the substrate on which the given species occurs.
The caramel crab (Hoplophrys oatesii) mimics the color and shape of the dendroneftia coral on which it lives.
In other cases, surrounding objects are used for cover. For example, bashful crabs cover themselves with a shield-shell, decorator crabs cut pieces of bryozoans, hydroids with claws and plant them on their backs, gluing them with special secretions. On the back of the crab, these colonial animals continue to develop and turn its shell into a flower bed.
It is difficult to recognize a well-camouflaged decorator crab (Camposcia retusa) in this creeping bush.
Dromia crab looks for a sponge and, like a real seamstress, cuts a piece out of it exactly the size of its back.
Dromia crab (Dromia erythropus) resembles an old woman in a beret. Since his body is rather fleshy, the drome has to look for a flap with a curve that perfectly repeats the bulges of his carapace.
If the disguise did not help, active methods of protection are used. Large crabs become in a fighting stance and raise their claws up. If the hint is not understood by the offender, they use their wire cutters and are able to inflict deep cuts. Boxer crabs always keep 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. Egg laying is visible on the abdomen of this individual.
Many species are capable of autotomy (self-amputation). At the sight of an enemy, the crab throws off its leg by contraction of special muscles. At the same time, the valves at the place of separation immediately close the wound and stop the bleeding. If such a handout was not enough, the victim offers the next limb to the predator. Severed legs grow back after several molts.