The coconut crab or palm thief is the largest representative of arthropods. coconut crab cancer palm thief

Palm thief, or coconut crayfish (Birgus latro) is a species of decapod crayfish from the superfamily of hermit crabs (Paguroidea) with a spectacular appearance. It is able to grow up to relatively giant size, it is likely that the palm thief is the largest among terrestrial arthropods in the world. Indeed, Charles Darwin described him as a "monster". Unlike most other hermit crabs, only very young coconut crabs find and use gastropod shells to protect their exposed belly. Later, tough skin develops there, as over the rest of the body. This protects the crayfish, reduces water loss and does not limit its growth, which allows the palm thief to reach 0.5 meters in length and weigh more than 4 kg.

photo:weedmandan

This huge crustacean is well adapted to life on land, with long, strong legs. It also has large, muscular claws that it uses to peel coconuts and open different shells. This is unique among crabs and explains why this species is called coconut. Its claws are actually so strong that the palm thief can lift objects weighing up to 20 kg. Its stalked red eyes and body color varies between islands from purplish blue to orange red. Studies show that the males of this species are significantly larger than the females.

photo:Andrew Lancaster

The palm thief is almost entirely terrestrial and has adapted to it so well that it actually drowns in water. However, it still breathes through modified gills. They are surrounded by a spongy "cloth" that must be kept moist. The coconut crayfish does this by dipping its foot into water and running it over its gills. The palm thief does require some contact with the sea, as it often drinks water to maintain its salt balance, and the females return to the sea to lay their eggs.

Photo: Jungle Diary

During the day, the palm thief sits in a hole where he is protected from withering and enemies, and at night he goes in search of food. As its name suggests, this crayfish feeds on coconuts. When coconuts are no longer available on the ground, he can climb a coconut tree, where he will pluck the coconut with his powerful claws. This crab also feeds on other fruits and other types of crustaceans, which are believed to provide it with calcium for carapace growth.

photo: marcushooi1

After mating on land, the female carries the fertilized eggs to the edge of the sea at high tide and releases the larvae. The larvae are pelagic and remain afloat in the sea for up to 28 days. In the amphibian stage, they are from 21 to 28 days, after which young crayfish occupy empty shells and migrate to land. They molt regularly to ensure their continued growth. Moulting takes place in a safe place and takes about 30 days, after which the palm thief eats the old exoskeleton. These crabs grow very slowly and have been proven to live for more than 40 years, after which they do not increase in size, although they continue to live for many years.

photo: Martin Navratil

The palm thief lives on oceanic islands and small offshore islands adjacent to large continental islands in a wide range geographical areas in the tropical Indo-Pacific region. It inhabits rock crevices and builds sandy burrows along the coastline. For example, on the island of Olango, Philippines, he lives in holes in coral rock, while on the island of Guam, in Oceania, he makes a hole inside the porous limestone.

Origin of the species and description

They do not like to live near people at all, and the more developed the island becomes, the less palm thieves remain there. Small, preferably generally uninhabited islands suit them best. They make their burrows near the coastline, in coral rock or rock crevices.

Interesting fact: Often these crayfish are called coconut crabs. This name arose due to the fact that it was previously believed that they climbed palm trees in order to cut the coconut and feast on it. But this is not so: they can only look for already fallen coconuts.

What does the palm thief eat

Its menu is very diverse and includes both plants and living organisms, and carrion.

Most often he eats:

• contents of coconuts;
• pandan fruits;
• crustaceans;
• and other small animals.

He does not care what he eats from living creatures - as long as it is not poisonous. He catches any small prey that is not fast enough to get away from him, and not careful enough not to catch his eye. Although the main sense that helps him when hunting is the sense of smell.

He is able to smell prey at a great distance, up to several kilometers for things that are especially attractive and odorous to him - namely, ripe fruits and meat. When the inhabitants of tropical islands told scientists about how good the sense of smell these crayfish had, they believed that they were exaggerating, but experiments confirmed this information: baits attracted the attention of palm thieves from a distance of kilometers, and they unmistakably aimed at them!

The owners of such a phenomenal sense of smell are definitely not threatened with death from starvation, especially since the coconut thief is not picky, he can easily eat not only ordinary carrion, but even detritus, that is, long-decomposed remains and various secretions of living organisms. But still prefers to eat coconuts. Finds the fallen and, if they are at least partially split, tries to break them with the help of claws, which sometimes takes a long time. It is not capable of breaking the shell of a whole coconut with claws - it was previously believed that they could do this, but the information was not confirmed.

Often they drag the prey closer to the nest to break the shell or finish eating the next time. It is not difficult for them to lift a coconut, they can even carry loads of several tens of kilograms. When the Europeans first saw them, they were so impressed with the claws that they claimed that palm thieves could even hunt goats and sheep. This is not true, but they may well catch birds and lizards. They also eat only newly born turtles and rats. Although for the most part they still prefer not to do this, but to eat what is available and so: ripe fruits and carrion that have fallen to the ground.

Features of character and lifestyle

You can rarely see them during the day, because they go out in search of food at night. In the light of the sun, they prefer to stay in the shelter. This may be a hole dug by the animal itself, or a natural shelter. Their dwellings are lined from the inside with coconut fiber and other plant materials that allow them to maintain the high humidity they need for a comfortable life. Crayfish always covers the entrance to its home with a claw, this is also necessary so that it remains wet.

Despite such a love for moisture, they do not live in water, although they try to settle nearby. They can often come to its very edge and get a little wet. Young crayfish settle in shells left by other mollusks, but then they grow out of them and are no longer used.

It is not uncommon for palm thieves to climb trees. They do this quite deftly, with the help of the second and third pairs of limbs, but sometimes they can fall - however, this is nothing to worry about for them, they survive a fall from a height of up to 5 meters without any problems. If they move backwards on the ground, then they descend from the trees head first.

They spend most of the night either on the ground, eating the prey found, less often hunting, or near the water, and in the late evening and early morning they can be found on trees - for some reason they love to climb there. They live for quite a long time: they can grow up to 40 years, and then they don’t die at all right away - individuals are known who have reached 60 years.

Social structure and reproduction

Palm thieves live alone and are found only during the breeding season: it begins in June and lasts until the end of August. After a long courtship, the crayfish mate. A few months later, the female waits for good weather and goes to the sea. In shallow water, she enters the water and releases eggs. Sometimes the water picks them up and carries them away, other times the female waits in the water for hours until the larvae hatch from the eggs. At the same time, it does not go far, because if the wave takes it away, then it will simply die in the sea.

Laying is done at high tide so that the eggs do not wash back to the shore, where the larvae will die. If everything went well, many larvae are born, which are not yet similar to an adult palm thief. For the next 3-4 weeks, they float on the surface of the water, noticeably grow and change. After that, small crustaceans sink to the bottom and crawl along it for some time, trying to find a home for themselves. The faster this can be done, the more likely it is to survive, because they are still completely defenseless, especially their abdomen.

An empty shell or a shell from a small nut can become a house. At this time, they are very similar to hermit crabs in appearance and behavior, constantly remain in the water. But the lungs gradually develop, so that over time, young crayfish come to land - someone earlier, someone later. Initially, a shell is also found there, but at the same time, their abdomen becomes harder and harder, so that over time the need for it disappears, and they discard it.

As they grow, they regularly molt - they form a new exoskeleton, and they eat the old one. So over time, they turn into adult crayfish, changing dramatically. Growth is slow: they reach sexual maturity only by the age of 5, and even by this age they are still small - about 10 cm.

Natural enemies of palm thieves

There are no specialized predators for which palm thieves are the main prey. They are too big, well protected and even dangerous to be constantly hunted. But this does not mean that nothing threatens them: large and, more often, birds can catch and eat them.

But only big bird, not every tropical island has such. Basically, they threaten young individuals that have not even grown to half the maximum size - no more than 15 cm. They can be caught by birds of prey such as kestrel, and so on.

There are much more threats to larvae: they can become food for almost any aquatic animals that feed on plankton. Mostly fish and marine mammals. They eat most of the larvae, and only a few of them survive to landfall.

We must not forget about the man: despite the fact that palm thieves try to settle on islands as quiet and uninhabited as possible, they often turn out to be victims of people. All because of their delicious meat, and the large size does not play in their favor: they are easier to spot, and catching one such cancer is easier than a dozen small ones.

Interesting fact: This crayfish was known as a palm thief because he likes to sit on palm trees and steal everything that glitters. If he comes across tableware, jewelry, and indeed any metal, the cancer will definitely try to take him to his home.

Population and species status

How many representatives of this species are found in nature has not been established due to the fact that they inhabit poorly inhabited places. Because they are not listed rare species, however, in those areas where records are kept, there has been a disturbing decline in their numbers over the past half century.

The main reason for this is the active capture of these crayfish. Not only is their meat delicious, and therefore expensive - palm thieves taste like lobsters; in addition, it is also considered an aphrodisiac, which makes the demand even higher. Therefore, in many countries, restrictions are placed on their production or bans on catching are introduced at all. So, if earlier dishes from this crayfish were very popular in New Guinea, more recently it has been generally forbidden to serve it in restaurants and eateries. As a result, one of the important sales markets for smugglers has been lost, although exports continue in large volumes, so there is still work to be done to prevent it.

In some countries and territories there are bans on catching small crayfish: for example, in the Northern Mariana Islands it is allowed to catch only those that are larger than 76 mm, and only under license and from September to November. For this entire season, under one license, you can get no more than 15 crayfish. In Guam and Micronesia, the capture of pregnant females is prohibited, in Tuvalu there are territories where production is allowed (with restrictions), and there are forbidden ones. Similar restrictions apply in many other places.

All these measures are designed to prevent palm thieves from disappearing. It is still too early to judge their effectiveness, since in most countries they have been operating for no more than 10-20 years; but the basis for comparison and selection of the optimal strategy for the future due to the variety of legislative measures in different territories is very extensive. These large crayfish need protection, otherwise people can simply exterminate them. Of course, certain measures are being taken, but it is not yet clear whether they are sufficient to preserve the species. On some islands where palm thief used to be widespread, they are almost never found - this trend cannot but frighten.

Animals such as coconut crab- a rarity in our nature. Another name for this creature is the palm thief. Why was it named like that?

These representatives of higher crayfish can be found on islands located in the Pacific and Indian Oceans, in the tropics.

The crab got its name "palm thief" for the habit of dragging everything it sees into its hole - a kind of "Plyushkin" among animals.

The appearance of this "claw-legged" creature is by no means attractive: it is very large and even scary! Anyway, let's take a closer look at it...

Appearance of a coconut crab

The animal grows to a very decent size: the body length of a palm thief can reach 35 centimeters, and its weight is about 4 kilograms.

The two front legs are equipped with claws and perform protective and grasping functions. With the help of such a device, the animal can easily crack the shell of nuts, such as coconuts.

This representative of crustaceans has another amazing ability: it has lungs, so it adapts to life on land and can do without water for a long time. But, it should be noted, when this "crab" becomes an adult, he does not need water at all, so his gills cease to function.

How does the palm thief live in the wild, and what does he eat?

These animals have a well-developed sense of smell, the coconut crab can smell the smell of food for several kilometers!

The main activity of the palm thief falls on the dark time of the day. It is at night that they come out in search of food. During the daytime, these crayfish hide in their shelter. It is a hole lined with fibers from the surface of the coconut shell.

The palm thief has an excellent ability to climb trees, especially palm trees. They can be found on a tree trunk at a height of six meters!

Coconut crabs are excellent poison dart frogs.

The nature of palm thieves is not very friendly, which makes them outcasts. But they don't really need everyone's attention!

The food of these animals consists of the pulp of coconuts, for which they were called coconut crabs. When the crab is in its teens, it lives in the water and feeds on small crustaceans and organic matter that it finds in the ground.

Reproduction of the palm thief

The mating season for these animals begins in July and ends in September. The fertilized female lays eggs and carries them on her belly until maturation. Then he leaves them in the water.

The larvae are free-swimming for about 30 days, and then they begin to seek shelter, which is most often the shell of a nut or a shell of a mollusk.

Palm thief meat is a rare delicacy.

Crayfish live in the house until they have their own shell. But the process of growing up does not end there. Next comes the molt. The body of the coconut crab changes a little and here it is. Finally, he becomes completely similar to the adult representative of the palm thief.

Just imagine you will see such a "cockroach" in your trash can :-)

The palm thief (Birgus latro), the coconut crab or thief crab, became famous after researchers from the universities of Lund (Sweden) and New South Wales (Australia) found that it has the same smell mechanisms as insects. This is the largest arthropod in the world (recall, they also include crustaceans, insects, spiders), up to half a meter long and weighing up to 4 kg. Like any crab, it has bristles and hairs of different lengths - tactile receptors.

But the coconut crab is unique in its kind, its sense of smell is as highly developed as that of insects, and besides, it has organs of smell that ordinary crabs lack. This feature of birgus latro developed after it emerged from the water and settled on land.

Clickable 2000 px

This thief with an incredible sense of smell is a creature whose appearance gave rise to many legends on the islands of the Pacific and Indian Oceans. If this giant crab throw it into the water, it will suffocate. His story is a typical example of "convergent evolution". So researchers call evolution, in which the same needs cause the same adaptation in organisms far from each other.

Like any crab, it has bristles and hairs of different lengths - tactile receptors. But the coconut crab is unique in its kind, its sense of smell is as highly developed as that of insects, and besides, it has organs of smell that ordinary crabs lack. This feature of birgus latro developed after it emerged from the water and settled on land. 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.

In "childhood" birgus latro is not too different from a hermit crab: he drags his shell along with him and spends almost all his 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. Once on solid ground, the coconut crab begins to drag everything that is poorly hidden (according to locals, he is seduced not only by food, but also by any shiny objects), and demonstrates his strength by splitting with pincers coconuts, behind which it climbs on palm trees to a height of up to 6 m.

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. If he wants to eat coconut, he cracks nuts, but it's a job - it takes weeks. Therefore, given that it moves well and fairly quickly, the thief crab prefers to use its powerful sense of smell in order to find edibles that do not have to be fiddled with - for example, food waste.

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. There are, however, those who are looking for a meeting with him: the crab is a well-known delicacy, and its meat is considered an aphrodisiac. 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.

With regard to reproduction, courtship in thief crabs can be long and difficult. The female, being slightly lighter than the male, carries fertilized eggs under her body, they are protected by three special processes.

When the eggs mature, the female goes to the surf line and leaves them at high tide so that the larvae can swim in the water for about a month. The "babies" then look for solid protection - a shell or nut shell - and exist as hermit crabs until they grow up to 2.5 cm in length. From that moment on, they shed their shells and their abdomens gradually harden through several phases of mutation during which they hide behind rocks. Apart from mating, the coconut crab does everything slowly and calmly: its growth phase is very long. So long that no one has yet been able to find out how long the thief crab lives.

scientific classification
Kingdom: Animals
Type: Arthropod
Subtype: Shellfish
Class: Higher crayfish
Detachment: Decapods
Superfamily: Hermit crabs
Family: Coenobitidae
Genus: Birgus
View: Palm Thief

On the inner surface of the walls of the gill cavities, this terrestrial descendant of hermit crabs develop grape-like 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 it uses plant material for their lining, which retains high humidity in housing.

In "childhood" birgus latro is not too different from a hermit crab: he drags his shell along with him and spends almost all his 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. Once on solid ground, the coconut crab begins to drag everything that is poorly hidden (according to local residents, it is tempted not only by food, but also by any shiny objects), and demonstrates its strength by splitting coconuts with its claws, after which it climbs up the palm trees to a height up to 6 m.

The palm thief, or as it is also called the coconut crab, is the world's largest representative of the decapod crabs from the superfamily of hermit crabs. Having studied the way of life of the palm thief, it is extremely difficult to call him a land arthropod, since he spends most of his life under water. Although the palm thief is not really a crab, although it is extremely similar to it. His appearance will make any person scared, as he looks like a terrible monster. And his claws can easily break bones, so it's best to avoid meeting in wild nature with this crab.

habitats

The palm thief also has many different names, for example: a thief - he received this name because he really steals booty, so according to the stories of travelers, this representative of arthropods hides in the grass and waits for the opportunity to jump out and drag its prey, which lies on the ground. It also has the name coconut crab - so it was called because he eats mostly coconuts, which is able to break with its powerful front claws.

The coconut crab is related to the common hermit crab and is very similar in appearance. But unlike him, palm thieves only use shells for two years, after which they discard them, since they have very durable exoskeleton.

These representatives of crabs live on the islands of the Indian Ocean, most of population is found on Christmas Island.

Appearance

The palm thief is the largest of the arthropods. The size of its body can reach a length of up to 40 centimeters, and the mass of the crab reaches four kilograms.

The body of the palm thief, like all representatives of arthropods, is divided into the front part, which includes all limbs and the stomach. The largest pair of legs are large and powerful claws, with which they can easily break coconuts. It can also be noted that the left claw is many times larger than the right one. The next pair of legs have sharp ends, with which they can safely climb any tree. The next pair of legs is responsible for protection when the palm thief is in his shelter and they also use it for walking. The last pair of legs is the smallest, it is mainly located inside the shell and is used only by females to care for eggs, while males use them in the mating process.

The palm thief's body is protected by a powerful calcified exoskeleton. Inside his body there is a special modification capable of producing gas exchange., which allows him to lead a terrestrial lifestyle. And also the arthropod has gills, but they are extremely poorly developed, so that it will not be able to live under water for a long time.

Lifestyle

• The diet of the palm thief includes various fruits of pandans, coconuts are a favorite delicacy, and it can also safely eat other representatives of arthropods. But in principle, the palm thief is an omnivore and can eat anything it finds as food.
• Coconut crabs live in the ground. To do this, they dig, with the help of claws, shallow minks, in which fibers from coconuts are covered. And I can also live in various crevices and coral reefs.
• Active activity is mainly shown in the dark. During the day they hide in their shelters.
• Representatives of arthropods live alone. Because they do not like other creatures. They are extremely aggressive towards anyone who enters his territory.

Reproduction of coconut crab

Crabs usually start breeding in the middle of summer, and finish with the advent of autumn. The courtship of the male for the female takes a long time, after which they mate. The female then carries the eggs on her belly. When it's time to hatch, the female puts eggs in water and leaves them there.

Crab cubs are born in the form of larvae, after which they swim freely for about a month, and then look for a place for themselves to live permanently. Having found a shelter, they sit there until they have a shell. This period lasts about twenty days. After that, they begin to molt, during which the body of the crab changes. Now he becomes like an ordinary representative of the palm thief.

Still a young crab lives mainly under water, but is already beginning to crawl out a little to the surface. As soon as the palm thief completely moves to land, he throws off the shell from his back and becomes like a hermit crab. They become fully grown crabs only in the fifth year of their life. A maximum dimensions they reach only by the age of forty.

Value for a person

This representative of crabs has always been very valuable for its uniqueness. Palm thief meat is a very rare delicacy.. It tastes like lobster or lobster meat. And also it is highly valued for the fact that its meat gives a strong aphrodisiac effect that promotes sexual desire.

Due to the mass hunting of crabs, the authorities of some countries were forced to ban the hunting of palm thieves in order to preserve their population.

• Representatives of palm thieves have a very highly developed sense of smell, so they can smell food for several tens of kilometers.
• Coconut crabs have an excellent ability to climb trees, so they can safely climb within a few seconds to a height of about ten meters.
• Although the crab's appearance is intimidating and capable of terrifying anyone who sees it. A large land crab is absolutely safe for a person if he does not touch it, in which case the crab can easily break the bones of the hand with its powerful claws.
• In Guinea, the meat of the palm thief was a traditional dish, until the moment when the government of the country banned the capture of these representatives of arthropods. Now it is a rare delicacy, for which you will have to pay a large amount of money.