Fish and other aquatic creatures



Animals like coconut crab are rare in our nature. Another name for this creature is the palm thief. Why was he called that?

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

Palm thief, or coconut crab (Birgus latro).

The crab got its name “palm thief” for the habit of hauling into its hole everything that it sees - a kind of “Plyushkin” among animals.

The appearance of this “claw-clad” creation is not at all attractive: it is very big and even scary! And yet, let's see it more closely ...

Appearance of coconut crab

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

The front pair of legs transformed into claws.

The two front legs are clawed and perform protective and grasping functions. With the help of such a device, an animal can easily crack the shell of nuts, for example, coconut.

This representative of crustaceans has another amazing ability: it has lungs, so it adapts to life on land and can go without water for a long time. But, it should be noted, when this “crab” becomes an adult, it doesn’t need water at all, therefore its gills cease to function.

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

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

The main activity of the palm thief is in the dark. That night they go out to search for food. In the daytime these crayfish hide in their shelter. It is a burrow covered with fibers from the surface of the coconut shell.

A 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 tree frogs.

The character 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 coconut pulp, for which they are called coconut crabs. When a crab is in adolescence, it lives in water and feeds on small crustaceans and organic matter that it finds in the ground.

Palm thief breeding

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

For about 30 days, the larvae are in free swimming, and then they begin to seek shelter, the role of which, most often, is the shell of a walnut or the shell of a mollusk.

Palm thief meat is the rarest delicacy.

In the house, crabs live until they have their own shell. But the process of growing up does not end there either. Further there is a molt. The body of the coconut crab is slightly modified and so. Finally, it becomes completely similar to the adult representative of a palm thief.

Commercial value

In culinary, these crayfish are a rarity, because they have a catch ban. It is believed that palm thief meat is a strong aphrodisiac.

Palm crab is a unique and amazing creature, though not very beautiful. Therefore, people must take measures to ensure that the population of these animals is preserved as long as possible on our planet!

Structure and systematic position

Palm thief is one of the largest terrestrial arthropods: body length can reach 32 cm, and weight - 4 kg. The claws of the front pair of walking legs are capable of developing an effort to crush small bones. The fourth and, in particular, the fifth pair of walking legs are less developed than the others. This feature, as well as the ability to turn down the abdominal section, indicate that palm thieves belonged to hermit crab, and not to crabs that look like crab.

The land way of life for representatives of this species allows for a powerfully developed calcified exoskeleton, as well as a modification of gas exchange organs. The walls of the gill cavities bear ugly outgrowths that significantly increase the respiratory surface. The gills of the palm thief proper are poorly developed.

Reproduction and development

In the breeding season, females with developing eggs migrate to the sea and lay them in the water, where the larvae hatch. The young individuals settled to the bottom have a typical appearance of hermit crab and hide the soft abdomen in empty sea shells (and after landfall - land) gastropods.

The lifespan of palm thieves is long enough: they reach 10 cm in length only at the age of five.

Nutrition and Lifestyle

The diet consists of the fruits of pandanas, the contents of chopped coconuts. Juveniles can feed on other crustaceans and detritus.

A palm thief digs up shallow burrows in the soil that lines the coconut fibers. Sometimes it is content with natural refuges - crevices in the rocks, cavities in the dried coral reefs, but even in such cases it uses plant material for their facing, which preserves the increased humidity in the dwelling. Able to climb trees. It has a well-developed sense of smell.

Palm thief eating coconut pulp. The abdominal region is bent, the fifth pair of walking legs is underdeveloped.

Birgus latro is a predominantly nocturnal creature and not very friendly, stumbling upon it, the locals do not have much enthusiasm. There are, however, those who seek meetings with him: the crab is a well-known delicacy, and its meat is considered an aphrodisiac.

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

Birgus latro, a coconut crab, or thief crab, became famous after researchers from the universities of Lund (Sweden) and New South Wales (Australia) found out that it has the same mechanisms of smell as insects. It is the largest arthropod in the world (they also include crustaceans, insects, spiders), up to half a meter in length and weighing up to 4 kg. Like any crab, it has bristles and hairs of different lengths - tactile receptors. But the coconut crab is the only one of its kind, its sense of smell is as strong as that of insects, besides it has organs of smell, which ordinary crabs are deprived of. This feature of birgus latro developed after it came out of the water and settled on land.

Swedish and Australian scientists have confirmed the veracity of all the stories about coconut crabs. For example, Pacific Islanders claimed that those over several kilometers could smell, for example, meat or ripe fruit. And indeed, special baits, planted by researchers, immediately attracted the attention of thieves crabs, who nevertheless disdained the usual pieces of bread, which are common crabs.

In the “childhood” birgus latro is not too different from the hermit crab: he carries his shell with him and spends most of the time in the water. But once he came out of the larval state and left the water, he was no longer able to return there, and at some point he would carry a small house with him. Unlike the abdomen of hermit crabs, its abdomen is not an Achilles' heel and gradually hardens, and the tail folds under the body, protecting the body from cuts. Thanks to a special light, he begins to breathe out of the water. Caught on firm ground, the coconut crab begins to drag everything that is badly tucked away (as locals say, it is not only food that seduces it, but also any shiny objects), and demonstrates its strength by cracking coconuts with its claws, behind which it climbs palm-trees to a height up to 6 m.

In truth, most of the legends noted precisely this feature of it - the first Europeans who arrived on the islands described coconut crabs as creatures with long claws hiding in the foliage of trees, which unexpectedly stretched to the very earth and captured prey, even 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 fruits. If he wants to eat coconut, he chops nuts, but this is still a job - it takes weeks. Therefore, given that he moves well and quickly enough, the thief crab prefers to use his powerful sense of smell in order to find edible, with which it is not necessary to bother, for example, food waste.

The caretaker's function is, of course, not bad and useful, however, since the birgus latro is a mostly night-time and not very friendly creature, having stumbled upon it, the locals do not have much enthusiasm. There are, however, those who seek meetings with him: the crab is a well-known delicacy, and its meat is considered an aphrodisiac. The decrease in its number forced the local authorities to set a limit on catching birgus latro. On Papua, New Guinea, it is forbidden to include it in restaurant menus, on Saipan Island, to catch crabs with a shell less than 3.5 cm, and also from June to September, during the breeding season.

As for breeding, the courtship of the thieves can be long and difficult. The female, being slightly lighter than the male, carries fertilized eggs under the 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. Then the "kids" are looking for solid protection - a shell or a nut-shell, and exist as hermit crabs until they grow up to 2.5 cm in length. From this point on, they discard the shell, and their abdominal cavity gradually becomes solid, having gone through several phases of mutations, during which they hide behind stones. Apart from mating, the coconut crab does everything slowly and calmly: its growth phase is very long. So long that no one has yet managed to figure out how much the thief crab lives.

Scientific classification
Kingdom: Animals
Type of: Arthropods
Subtype: Crustaceans
Class: Higher Crayfish
Squad: Decapods
Superfamily: Hermit crabs
Family: Coenobitidae
Rod: Birgus
View: Palm Thief

Coconut crab: where it is found

The habitat of such an amazing monster can be considered the Indian Ocean islands, in particular, Christmas Island, where these arthropods are represented in their largest concentration. Christmas Island is considered the territory of Australia and is located 2,600 km to the north-west from the city of Perth. Being the birthplace of coconut crab, Christmas Island has become famous for its other feature that has become a landmark and its hallmark. This is the migration of red crabs, which every year, in the amount of more than 50 million individuals, move from the forests to the coast of the ocean for breeding purposes. Moreover, such a massive journey covers the entire area of ​​the island and takes about a week by temporary standards. During this period, most of the roads are closed to all types of transport.

The largest arthropod, coconut crab, also successfully settled down and feels great on the western part of the islands of the Pacific Ocean - the largest ocean on the planet, striking a variety of life forms.

Coconut Crab Sizes

The average height of such an interesting specimen - coconut crab is 40 centimeters with a small weight (only about 4 kg), the length of one claw in its expanded form can exceed 90 centimeters. The life expectancy of an arthropod is about 60 years, although, according to scientists, this is a controversial issue and this age, due to the slowness of the life cycle, may exceed the estimated number. The coconut crab, which at the age of 5 reaches only 10 centimeters in size, is very popular with exotic lovers, many wonder-gatherers dream of replenishing their collections with such a cute pet.

Coconut Crab: Description

The body of coconut crab consists of two halves. The first is the head with ten legs, which is the front part, the second half is the abdomen. The front, most massive pair of legs is equipped with large claws, while the left claw is an order of magnitude larger than the right one. The next two pairs of legs, like the rest of the crabs, powerful and big, end in sharp ends. Thanks to them, crabs can easily overcome inclined or vertical surfaces. The fourth pair of legs is much smaller than the previous three and allows the young coconut crab to settle in the shell of coconuts or shells of mollusks for protection. The fourth pair is used by adults for walks and mountaineering. The last pair of paws, the smallest and least developed (as well as the fourth pair), usually hides inside the shell. It is used by males for mating, and females in the care of eggs. A coconut crab, whose photo fully conveys its unusual beauty and causes emotions of unstoppable fear, is in fact a harmless creature, unless, of course, you have to worry about it and take a closer look at it. Otherwise, you can stay without fingers.

Where does the crustacean monster live?

The habitat of coconut crab is exclusively dry; an adult cannot live in water due to the fact that the gill lungs (a cross between gills and lungs) are adapted for breathing ground air, despite the fact that tissues present in such a respiratory organ are present. gills. Rather, the ability to live in two environments (aquatic and terrestrial) is present at the initial life stage of the crab, as it grows up, such an individual moves to the land way of life. In addition, these arthropods do not know how to swim at all and will be drowned for more than an hour when they are in the water. The exception is when the coconut crab is still in the larvae stage, in this case the aquatic environment is native to it.

Coconut crab lifestyle

It is not easy to meet a coconut crab in the daytime, because it prefers to lead a nightlife, hiding in sunny time in sandy holes, cavities of coral reefs or crevices of rocks, the bottom of which is lined with foliage and fibers of coconuts. The coconut thief does this - “Crab with a capital letter” in order to maintain the optimum level of humidity in his home. Also during the holidays, he closes the entrance to his dwelling with one claw. This also contributes to the saving of a comfortable microclimate for a palm dweller.

The first impression of coconut crab

From the point of view of the first Europeans who arrived on the coconut crab habitat islands, the latter appeared to them as a creature with long claws, hiding in the green foliage of palm trees and suddenly catching prey passing under or under a tree, among which there were even goats and sheep. Indeed, palm coconut crab is the largest representative of decapod crayfish, it has tremendous strength and is capable of lifting a weight of about 30 kg. Mostly this skill is used by the crab to drag prey from place to place, and in the diet it prefers dead animals, crabs (of course, a little smaller than himself), young turtles and fallen fruits, in particular, pandan fruits and the contents of chopped coconut nuts. palm trees Also palm thieves (the second name of the coconut crab) were caught catching and eating Polynesian rats and gutting garbage cans, where they are looking for some kind of “snack”. Moreover, the presence of people is not at all the formidable factor that palm coconut crab would be afraid of. The photo clearly conveys the desire of the clawed to profit, the more he has a formidable weapon - huge claws of frightening dimensions.

What eats palm thief

Based on the name of the crab, we can conclude that coconuts are the favorite food for it. This arthropod is able to quickly climb palm trunks, and the conquest of 6-meter height for him is quite a habitual occupation. Looking from the side, as a huge multi-legged monster crawls along a smooth tree trunk, along with the delight of such an unusual spectacle, any person will experience fear and horror from the strangeness of what is happening: it would seem that the crab, the inhabitant of the water element, is also on the tree! Is it a paradox ?! The crab plucks coconuts with powerful claws, which fall to the ground and break. If the nut remains intact during the fall, the coconut crab will persistently gut it in order to get to the juicy nut pulp, this monotonous process can last more than two weeks. При безуспешности всех попыток ракообразное будет добиваться своей цели иным способом. Пальмовый вор (кокосовый краб, то бишь) поднимет плод обратно на пальму и снова сбросит вниз. Хотя информация о настойчивом раскалывании кокосовых орехов по некоторым данным является непроверенной, на самом деле крабы питаются уже расколотыми плодами, упавшими с дерева и лежащими на земле.

When descending to the ground, crabs, because of their own clumsiness, are sometimes not held and fall down. Without prejudice to themselves, they can safely move the fall from 4-5 meters in height.

Interesting features of coconut crab

Thanks to special organs located on antennas that determine the direction of smell and its concentration, coconut crab, unlike its crustacean relatives, has a great sense of smell. Like any crab, it has tactile receptors: hairs of different length and bristles. In addition, it has organs of smell, which are deprived of the rest of his brothers. Their presence is due to the specific features of the development of a palm thief, who at one moment failed to exist in the water and moved to live on dry land. Being hungry, he hears his prey even at a distance of several kilometers.

"Palm Thief" - coconut crab received its second name for the love of everything brilliant. If any brilliant object (such as a spoon, fork, metal appliance, household utensils, or something more attractive) meets the arthropod's path, the crab will not crawl by and will surely profit by an interesting find (even if the latter is completely inedible) crab lair.

Measures taken to save coconut crab

Separately, I want to talk about why so much appreciated coconut crab. The photo of such a monster with huge claws clearly does not cause sympathy for him. Why do women and men love him so much, if there is a constant hunt for such a unique islander? In addition to what is considered a delicacy, coconut crabs meat is also an aphrodisiac (a substance that triggers the process of sexual arousal in the body and enhances sexual attraction in the female and male sex), which leads to the maintenance of a rather intensive hunt for this arthropod species. It tastes like lobster or lobster meat and is cooked in the same way.

The most traditional dish on the islands is coconut crab, served with coconut milk sauce or boiled in such milk for a little over a quarter of an hour. By the way, in Guinea in order to save the coconut crab population of the latter it is forbidden to include in the restaurant menu.

In some countries, in order to prevent complete extinction, there are strict restrictions on the capture of coconut crabs. Thus, on Saipan Island, a ban has been imposed on catching crabs during the breeding season and on individuals whose shell size is less than 3.5 centimeters.

Tricks coconut crab

Although, for curiosity's sake, it's still interesting how they catch such huge, fearful centipedes? On the Mariana Islands for them arrange coconut baits, in which the coconut itself is finely rubbed. This bait is left for a couple of days for "souring", necessary for the crab to smell the dinner prepared for it. The trap does not even need to be hidden, it only needs to be tied to some tree so that the crab could not drag off its prey in an unknown direction.

Reproduction palm thieves

From early June to late August, palm thieves begin to multiply. The process of courtship lasts a long time, while the pairing occurs many times faster. For several months, the female bears fertilized eggs on the underside of the abdomen, and at the time of hatching, the female coconut crab releases the larvae into seawater at high tide. Over the next three to four weeks, the larvae swimming in the water go through several stages of development. After 25-30 days, already full-fledged crabs sink to the bottom, where gastropods live in the shells or in the shell of nuts, preparing gradually for migration to dry land, which is periodically visited.

How is the development of small crab

In this period of life, with a sink on the back, the crabs very much resemble hermit crabs and carry the house until the belly starts to harden. Further, in the development of the young crab, a period of molting occurs, during which the arthropod repeatedly drops its shell. The final stage of "growing up" of a young crab is the turning of its tail under the abdomen, which causes a kind of protective measure against possible damage. As they grow, crabs gradually lose the ability to breathe under water and soon finally move to their main habitat - on dry land.

Coconut crabs reach maturity about 5 years after hatching, reaching a maximum size of about 40 years.