Fascinating facts about starfish that you probably didn't know. Starfish in a home marine aquarium Ocean star

The underwater world is full of diversity. Among others, special attention is paid to the animals that live on the bottom - starfish. They can come in different shapes and colors. To talk about the most interesting species, we have created a selection that includes 10 of the most amazing starfish.

Starfish, ever since their discovery, have fascinated humanity. This is also confirmed by their high importance in some cultures and tribes. Perhaps the most common image of a starfish in art is Patrick from the cartoon about SpongeBob, so these crested ones are considered by many to be exclusively pink in color and perfectly proportional. Of course, wildlife is much more diverse, offering other shades and forms.

Among the most beautiful starfish in the world you will even notice those who would never be classified as such a species by eye. In our country they are very rare, because they prefer to live in warm regions, so interest in exotic creatures is only increasing.

1. Royal starfish (Astropecten articulatus)

The habitat of this species is the east coast of North America, where they can be easily found on the beaches. Previously, they lived only at a depth of about thirty meters, but now they rise higher and higher to find food and avoid predators. In the main part of the body, dark shades predominate, but the rays are most often red, orange or white. They are usually called “gluttons”; researchers have repeatedly noticed a swollen ball in the very center of the creature, which was a full stomach. Absorbing all the caught plankton whole, it is most often not able to digest it completely, so it spits out the remains.

2.

It is false to believe that one of the most unusual starfish on the planet is exclusively square in shape. This form is seen in only one individual out of ten, but even healthy creatures differ significantly from their relatives. Firstly, their rays are not separated from each other, that is, it looks more like a pentagon than a star. Secondly, their extraordinary thickness and shape are more reminiscent of freshly baked cookies or an ottoman for an armchair, which is why they got their name. The fact is that in English, biscuit means cookies, but domestic translators suggested that “gingerbread starfish” somehow doesn’t sound right.

3.

Before you is not only one of the most beautiful, but also the only poisonous starfish. In addition to its danger to humans, it causes significant damage to coral reefs, because they are its favorite food. Its gluttony allows this predator to destroy two square meters of polyps in just one day, enveloping each of them with its body and then dissolving it with poison. The number of rays is usually a multiple of five and ranges from 10 to 25, depending on age; blue, green and purple predominate among the shades. Under no circumstances take it with your bare hands - the needles will instantly inject poison, which, in the absence of timely assistance, will cause serious disruption of the nervous system.

4.

When planning to go on vacation to Egypt or Israel, be sure to pay attention to one of the most beautiful starfish on the planet. It is elegant, has an ideal five-pointed shape and an unusual color. Even for inexperienced divers, meeting it will not be a problem: individuals can be found already at a depth of five meters. The most common shades are red and orange, diving deeper you can see completely white or brown individuals. It is absolutely safe for humans, so do not hesitate to touch it with your hands.

5.

This creature got its name due to the perfect combination of two pentagons. The inner one looks like a biscuit star, even has almost identical dimensions, and the outer one has rays and gives the starfish a traditional shape. It does not have a clear range or depth of habitat, but the chance of finding it in the Indian Ocean is extremely high. The color is dominated by shades of beige and gray, and each ray is fragmented into small squares with veins.

6.

At first glance it looks quite ordinary, but if you take a closer look, you will be able to appreciate the whole variety of colors. The body itself is the same color, but the areas in front of the spines create a significant contrast, and the processes themselves are radically different. The horned star is usually chocolate-colored, but white and orange specimens can also be found. Due to their tiny size and strong skeleton, it is quite difficult for them to feed on their own, because a potential victim can simply swim into a gorge where the star cannot reach. This is precisely what becomes the main reason for the frequent death of representatives of this species in artificial conditions, as well as their love for the destruction of small invertebrate animals responsible for the cleanliness of the aquarium ecosystem.

7.

The most beautiful starfish in the world are sometimes very different from their relatives. This species is notable for the fact that it can be found in cold waters in the Sea of ​​Okhotsk area. Externally, the crossaster more closely resembles an octopus; the sphere, which is the body, is most often bright red, but the rays, the number of which ranges from 8 to 11, are pure white. She holds the record for the fastest movement of her family; young individuals can even cover a meter in a couple of seconds. And the diet is very unusual: most often it is a small fish; there have even been cases of attacks on victims significantly larger than the crossaster in size.

8.

Another representative of our homeland, its habitat is limited to Peter the Great Bay in the Sea of ​​Japan, where at a depth of about thirty meters it can be found everywhere. The rays are perfectly straight and extremely mobile, usually reaching as much as twenty centimeters in length, and their tips are bright orange, which contrasts qualitatively with the predominant white tint. The entire body is covered with needles, which perform two important tasks at once: protection from predators and camouflage, because at such a depth it is quite difficult to distinguish Dystolasteria from stones and algae.

9.

An inhabitant of the waters of Southeast Asia will amaze you with the number of shades present in its color. In the center there is a bright spot, red or purple, the rays are covered with tubercles, the color of which is different and extremely rarely coincides with at least one of the shades present on the fromia. However, aquarists who want to acquire such beauty will have to work hard: it does not react at all to artificial food, so they will have to spend about a year creating living conditions close to natural ones, otherwise the life expectancy of Phromia will be less than a year. True enthusiasts are confident that such a demonstration of a natural wonder is worth the effort.

If you find yourself in the Dominican Republic, don’t miss the chance to visit the Blue Lagoon and get acquainted with its beautiful and unusual inhabitants - starfish. You will find shocking facts about these creatures in this article!

Starfish are not just beautiful decorations and decoration of the seabed. At first glance, they seem primitive and somehow unreal. But appearances are deceiving. These animals have a complex nervous and digestive system.

Well, for example: did you know that the starfish is a real predator? And stars can move along the seabed over considerable distances. And this is not all that is known about starfish.

Facts about starfish

We have collected for you the most interesting facts about these amazing animals.

According to the texture of the body surface, starfish are:

• smooth
• spiky
• prickly
• rough
• velvety
• mosaic
• plain and patterned
• bright and faded

Starfish come in a wide variety of colors. Most often this

• various shades of red
• blue
• brown
• pink
• violet
• yellow
• black

The deeper the sea star's habitat, the paler it is. Those individuals that live in shallow waters are distinguished by the brightest colors.

Food and hunting

Starfish have a kind of sense of smell - they are able to detect chemicals. This helps them hunt.

Yes, yes - most starfish are real predators!

Here are just some of the inhabitants of the seabed that the stars hunt:

• shellfish
• crustaceans
• plankton
• sponges
• corals
• gastropods
• other invertebrates, including echinoderms. For example, sea urchins are one of the starfish’s favorite delicacies.

The process of hunting, absorption and subsequent digestion of prey requires a separate story. We advise the faint-hearted and impressionable to scroll through these details.

The starfish is not picky about food and eats everything it can digest. She does not disdain carrion.

On the abdomen of the starfish there is a mouth through which it absorbs prey. If any mollusk becomes its victim, then the starfish crawls onto it and sticks with its rays to its valves. Thanks to the adhesive lubricant, the star manages to stick very firmly to the shells of the mollusk.

After this, a long struggle begins: the mollusk squeezes the valves of its shell, protecting itself from the predator, and the star strives to open them to gain access to the contents.
As a rule, the outcome of this confrontation is disastrous for the mollusk: the starfish is much stronger. And besides, for a hearty lunch, a gap of only 0.1 mm is enough for her!

Then something fantastic happens: the starfish turns out its stomach, which can stretch up to 10 centimeters! The stomach penetrates the shell of the mollusk, where the entire digestive process takes place, lasting several hours.

Thanks to its expandable stomach, the starfish can even digest prey that is significantly larger than its size. There is a known case where a starfish died after swallowing a sea urchin so large that it could not spit out the remains.

Reproduction

Starfish reproduce in different ways:

• Reproduction by regenerative means.

Due to the softening of the connective tissue, the starfish breaks up into several parts or casts off its rays. Then full-fledged stars grow from these parts.

• Sexual reproduction.

In a starfish, the gonads are located in pairs at the base of each ray. During mating, males and females connect their rays and release sperm and eggs into the water.

Those species of starfish that bear offspring lay 200 or more eggs.

Female starfish, whose larvae are free-swimming, are capable of laying up to 200 million eggs!

Among starfish there are also unisexual species. The bodies of such stars produce both male and female reproductive products. They carry their offspring in a brood pouch or special holes on their back.

And there are also species that during their lives change sex from male to female (for example, the asterine starfish).

There are three types of starfish larvae:

• in one type of star, the egg hatches into a larva that swims freely and feeds on tiny pieces of algae. After a few weeks, it attaches to the bottom and gradually turns into a small star with a diameter of 5 centimeters.
• in another type, the larva has large reserves of yolk, which allows it to do without additional nutrition and grow into an adult star
• in those stars that live in cold waters, the larvae remain on the mother’s body and concentrate around her mouth. Therefore, during this period, the female has to do without food and move very, very carefully, arching her body so as not to harm the larvae.

The size of the larvae usually does not exceed 3-5 mm

Starfish larvae can be carried over enormous distances by currents.

The starfish becomes sexually mature only at the age of 2-3 years.

The starfish is almost invulnerable. It is protected from natural enemies by:

• sharp thorns (sometimes poisonous)
• ability to bury itself in sand in case of danger

• shrimps
• shellfish
• polychaete worms

They settle on the back of the starfish and cause damage to its covering. The star herself tries by all means to get rid of uninvited guests.

Benefits for the eco system

Starfish have a positive effect on the ecology of the oceans and the planet as a whole:

• absorb and utilize carbon dioxide, harmful to the planet, which is becoming more and more in the Earth’s atmosphere every year
• are orderlies of the seabed, eating carrion and the remains of dead marine organisms, as well as weaker and sicker individuals of marine animals

Some of the most colorful and beautiful representatives of this species live near the southern coast of the Dominican Republic. You can get to know them by visiting the Blue Lagoon. A visit to this natural pool, located right in the middle of the Caribbean Sea, is included in all excursions to the island of Saona.

The Blue Lagoon, as well as the islands of Saona, Catalina and Catlinita are part of the Eastern National Park. And all the nature in these territories is carefully protected.

The lives of starfish are also protected. In order to preserve the population of this species, as of October 2017, it was prohibited to remove starfish from the water. And yet, starfish, as before, decorate the bottom of the water area and no one will stop you from admiring them.

Let's take care of nature and the fragile lives of starfish!
And then everyone will be pleased to return to the Blue Lagoon again and again to visit their old star acquaintances.

Sea stars- amazing creatures that look so beautiful on the seabed! Today, friends, we want to tell you a little about them, starting with their general characteristics.

Description of starfish

Echinoderms There are about 1600 species, but today we will list the main ones. The size of the stars ranges from 1 mm to 25 cm, it all depends on the species. Of course, each view is beautiful and colored in its own way, some stars are bright, others are barely visible in the sea. The rays of the star serve as digestion, because it is in them that the processes of both the genital organs and the stomach itself are located. The starfish also has legs and a mouth!

The stars feed plankton, detritus, barnacles, clams, oysters, mussels and even corals! A life expectancy its average age is 20 years.

Interesting facts about starfish

The legs of a starfish are usually equipped with suction cups to make it convenient to move along the seabed.

Most starfish are predators

Dioecious stars

Stars reproduce right in the water, sweeping out both sperm and eggs.

Usually the fertilized “larva” is attached next to the parent, but some carry the baby in a special pouch

HABITAT AND SPECIES OF SEA STAR

Types of starfish

1. Ludia two-needle

2. Patiria comb

3. Solaster pacific

4. Henricia Hayashi

5. Lysastrosoma antisticta

6. Dystolasteria causticus

7. Letasteria nigra

8. Aphelasteria japonica

9. Eusteria spinosa

10. Eusteria reticularis

11. Common Amur star

Where do starfish live?

Sea stars are the oldest group of animals that have survived to our age! And strangely enough, a marine representative can be found in almost every salty sea and every ocean. By the way, it is in those seas where there is normal salinity that starfish can be found on the shore! It is for this reason that humanity has known about them since ancient times.

VIDEO: ABOUT SEA STARS IN THIS VIDEO, WE INVITE YOU TO WATCH A DOCUMENTARY ABOUT SEA STARS

Starfish are animals with an unusual body shape, thanks to which they attracted the attention of people back in ancient times. Starfish belong to the phylum Echinodermata, in which they are classified as a separate class, numbering almost 1,600 species. The closest relatives of these invertebrates are brittle stars, or snaketails, which are very similar to them, and more distant relatives are sea cucumbers and sea urchins.

The main distinguishing feature of starfish is, of course, their body shape. In general, the body of starfish can be divided into a central part - the disk, and lateral outgrowths, which are usually called rays or arms. These animals are characterized by radial symmetry, so their body is divided into symmetrical sectors, the number of which is usually five. However, among starfish there are organisms with a large number of axes of symmetry: in some species their number can reach 6-12 and even 45-50.

Nine-armed starfish (Solaster endeca).

Each sector, accordingly, includes part of the central disk and a hand. It would seem that such a similar structure should result in the monotony of these living organisms. But the body shape of starfish is very variable. Firstly, the relative length and thickness of the rays varies greatly: in some species they are elongated and thin, in others they have a triangular shape, sharply tapering towards the end, in others the rays are so short that they practically do not protrude beyond the edges of the central disk. The latter type of stars have a very high central disk, so they resemble pillows. Thus, in most species of sea stars, the length of the rays is 3-5 times greater than the diameter of the central disk, in the longest-armed ones it is 20-30 times, and in the cushion-shaped ones it tends to zero.

This colorful ottoman on the seabed is actually the New Guinea starfish (Culcita novaeguineae).

Secondly, starfish differ in surface texture and color. Here the variety simply defies description - smooth, spiky, prickly, rough, velvety, mosaic; monochrome and patterned, bright and faded. The color range of these animals includes almost all colors, but most often there are various shades of red, less often blue, brown, pink, purple, yellow, and black. Pale sea stars usually live in the depths, while shallow-water species are brightly colored.

This is the same New Guinea kulzita, but of a different color.

At first glance, starfish seem primitive, because they do not have any noticeable sensory organs, a brain, and poorly differentiated internal organs, but this simplicity is deceptive.

The Linkia starfish (Linckia laevigata) is bright blue in color and has sausage-like rays.

First of all, it should be noted that starfish have an internal skeleton. They do not have a backbone or individual bones, but have many calcareous plates connected to each other in an openwork system.

Openwork plexuses of skeletal elements on the surface of a starfish.

In a young starfish, the skeletal elements are hidden under the skin, but over time the skin over some calcareous spines wears off and they become visible from the outside. It is these spines that give starfish their spiny appearance.

The spines on the surface of the starfish are covered with skin, but some of them are already exposed and have a shiny surface.

In addition, on the upper side of the body in many species, calcareous plates may be visible, fused together or forming a network.

A bizarre pattern formed by the skin and skeletal elements of a starfish.

Finally, the third element that influences the appearance of a starfish is pedicellaria. Pedicellariae are modified needles that look like tiny tweezers. They play an important role in the life of a starfish; with their help, it cleans the upper side of its body from debris and sand. All skeletal elements are connected to each other by muscles, so after the death of a starfish, its skeleton crumbles into calcareous plates and not a trace remains of the animal.

The acanthaster starfish, or crown of thorns (Acanthaster ellisii) has spiny and poisonous spines.

The muscular system of starfish is relatively poorly developed. Each ray has a muscle cord that can bend the ray upward, and this, in fact, limits the muscle movements of the stars. But mobility is not limited at all. Starfish can crawl, dig, bend, and swim, but they do not do this with the help of muscles.

Scalloped sea stars (Patiria pectinifera) climb on the seaweed.

These animals have a special body system - ambulacral. Essentially, this system consists of channels and cavities connected together and filled with liquid. The starfish can pump this fluid from one part of the system to another, causing its body parts to flex and move. The central part of this system is the ambulacral legs - tiny blind outgrowths of the ambulacral canals on the underside of the starfish. Each leg moves independently of the others, but their actions are always coordinated. With the help of these microscopic elements, the starfish is able to perform miracles. For example, it is able to climb a vertical surface, can stick to the glass of an aquarium for a long time, can rear up, swelling up like an angry cat, or maybe, grabbing hold of two rays, push the valves of a mollusk shell apart. And all this is done by an animal practically devoid of a brain and eyes!

Translucent ambulacral legs are visible on the underside of the beam.

To be fair, it is worth noting that starfish do have some sense organs. These are the eyes located at the ends of each ray. The eyes are very primitive and only distinguish between light and darkness; starfish cannot see objects. Starfish are capable of detecting chemicals (analogous to smell), but they sense them differently. Some species are very sensitive and can crawl to the bait for several days in a row by smell, while others can crawl past the victim a couple of centimeters and not smell it. Sea stars have a very developed sense of touch; they try to get rid of the sand that covers them from above, and also always try to feel their way with the help of small tentacles at the end of each ray. The sense of touch tells the starfish whether it has encountered a victim or a predator. The starfish's brain is replaced by a group of loosely interconnected cells. It is surprising that despite such a primitive structure of the nervous system, starfish can develop elementary conditioned reflexes. For example, starfish that were often caught in nets began to get out of them faster than those that were caught for the first time.

At the end of the ray of the asterodiscus starfish (Asterodiscus truncatus) a formed eye is visible. The beam itself is covered with relief limestone plates.

Another “strong” system, in the literal and figurative sense of the word, of starfish is the digestive system. The mouth of these animals is located in the center of the disc on the underside, and the tiny anus is located on the dorsal side of the body. By the way, starfish rarely use it (in some species it even becomes overgrown), preferring to remove food debris through the mouth. The stomach of starfish has projections extending into rays; in these projections, reserves of nutrients are deposited in case of famine. And starfish regularly starve because they stop feeding during reproduction. The stomach in many species can turn outward through the mouth opening, and it stretches like rubber, taking any shape. Thanks to its expandable stomach, the starfish can digest prey that is larger than itself. There is a known case when the starfish Luidia swallowed such a large sea urchin that it died, unable to spit out its remains.

A tiny anal opening is visible in the middle of the central disc of Phromia monilis.

Other body systems are poorly developed in starfish. They breathe through special outgrowths of the skin on the upper side of the body, washed by sea currents. They do not have gills or lungs, so starfish are sensitive to lack of oxygen. They also cannot tolerate desalination of water, so they are found only in seas and oceans. The size of sea stars ranges from 1-1.5 cm for the miniature spherical star Podosferaster to 80-90 cm for the sea star Freyella.

The name of this starfish speaks for itself - elegant fromia (Fromia elegans).

Starfish have a global distribution. They are found everywhere in all seas and oceans from the tropics to the poles. Of course, species diversity is higher in warm waters than in cold waters. Most species prefer to live in shallow waters, some even end up on the shore during low tides. But among these animals there are also deep-sea species, including those that live at depths of over 9 km!

Starfish in shallow water.

Starfish crawl along the bottom most of the time, they do this very slowly, the usual speed of an average-sized starfish is 10 cm per minute, but a starfish can “hurry up” at a speed of 25-30 cm per minute. If necessary, starfish can climb onto rocks, corals, and algae. If a starfish falls on its back, it immediately turns over with its ventral side down. To do this, the animal bends two rays so that the ambulacral legs on the lower side touch the ground, and then the starfish turns its body and takes its usual position. Some species are even capable of swimming awkwardly over short distances. Starfish can be called sedentary animals; tagging of animals has shown that they do not move more than 500 m from the place of initial catch.

The coriaster starfish (Coriaster granulatus) looks like a bun.

Despite their outward primitiveness and apparent helplessness, starfish are formidable predators. They are quite voracious and never refuse prey, with the exception of the period of gestation. Only deep-sea species feed on silt, from which they extract food particles; kulcite sea stars, which prefer to eat fouling on corals, can also be called conditionally “non-predatory”. All other species actively hunt other animals.

A completely non-romantic relationship ensued between the sea star Solaster dawsoni and Hippasteria spinosa.

Most starfish are picky; they eat everything they can hold with their hands and whatever their “rubber” stomach can reach, not disdaining carrion. Some species can only feed on a certain type of food: sponges, corals, gastropods.

The pretty starfish (Pentagonaster pulchellus), also called the biscuit starfish for its biscuit-like body shape.

The favorite prey of sea stars are sedentary animals like themselves - sea urchins and bivalves. The star catches the sea urchin by crawling and eats it with its mouth. Bivalves have shells whose valves close tightly in case of danger, so starfish treat them differently. First, the starfish sticks with two rays to the shell flaps, and then begins to move them apart. It must be said that the ambulacral legs are firmly glued to the substrate thanks to an adhesive lubricant, and one single ambulacral leg can develop a force of up to 30 g! And on each ray of the starfish there are hundreds of them, so the star, like a real strongman, pushes the shells apart with a force of several kilograms. However, the starfish does not need to spread the shell flaps to their full width; for a hearty lunch, a gap of 0.1 mm is enough for it! The starfish turns its stomach into this truly microscopic gap (it can stretch up to 10 cm) and digests the mollusk in its own home.

Asteria starfish (Asterias rubens) reaches out to a clam.

Most starfish are dioecious; very few species have both male and female gonads. The gonads are located in pairs at the base of each ray. In the asterine starfish, the young are first male and then change to female. A special exception is the ophidiaster starfish, which has... no males at all. Females of this species lay eggs without fertilization, a process called parthenogenesis. During mating, males and females connect their rays and release sperm and eggs into the water. The number of eggs depends on the type of development of the larvae and ranges from 200 in those species that bear offspring, and up to 2-200 million in species with free-swimming larvae.

Mating starfish.

Starfish larvae come in three types. In some species, the eggs hatch into a free-swimming larva, which feeds on microscopic algae, and then attaches to the bottom and gradually turns into a small star. In others, the free-swimming larva has large reserves of yolk, so it does not feed and immediately turns into an adult form. In starfish that live in cold waters, the larvae do not separate from the mother’s body at all, but accumulate near her mouth or even in special stomach pockets. During this period, the caring female rests only on the tips of the rays, and arches her body into a dome, under which the larvae are located. Since the larvae are located near the mouth opening, the female does not feed during this period. The larval form is the most mobile in the life cycle of sea stars; it is during this period that the larvae can be carried by currents over very long distances.

The starfish larva has bilateral symmetry.

In addition to sexual reproduction, starfish can also reproduce asexually. Most often this occurs in multi-rayed species; the body of the animal is divided into two halves, each of which builds up the missing rays. In other species, asexual reproduction may be the result of regeneration following traumatic damage to the body. If a starfish is artificially divided into several parts, then a new organism will be formed from each. Even one beam is enough for restoration, but a piece of the central disk is required. Starfish grow slowly, so they look lopsided for many months.

A seagull caught a starfish.

But the starfish Astropectens is friends with polychaete worms. One star can have up to five cohabitants who prefer to stay on the lower side of the body close to the star’s mouth. The worms pick up the remains of the star's prey and even... stick their heads into its stomach. The echinaster sea star is inhabited by a special type of ctenophore, which cleans the surface of the star from fouling.

These bright spots on the Luzon starfish (Echinaster luzonicus) are ctenophores (Coeloplana astericola).

Since ancient times, people have paid attention to the colorful animals of shallow waters, but starfish were of no economic interest to them. Only in China are starfish sometimes eaten, while attempts to feed starfish to domestic animals can lead to the death of the latter. This is likely due to toxins that some species accumulate by eating coral and poisonous shellfish. But with the development of the maritime economy, people began to classify starfish as their enemies. It turned out that starfish often eat bait in bottom crab traps, and also raid plantations for breeding oysters and scallops. In a few years (that’s how long it takes to grow oysters), starfish can destroy an entire oyster bank. At one time they tried to destroy starfish by cutting them into pieces, but this only increased their numbers, because from each stump a new starfish grew. Then they learned to extract starfish with special trawls and kill them with boiling water.

A very impressive mosaic starfish (Iconaster longimanus).

The worst pest was the acanthaster starfish, or crown of thorns. This very large starfish feeds exclusively on corals; after itself, the crown of thorns leaves only a white lifeless trail on the coral reef. At one time, these stars multiplied so much that they literally destroyed a huge section of the Great Barrier Reef off the coast of Australia. The unique geological formation was under threat of destruction. The fight against the crown of thorns was complicated by the fact that its thorns are poisonous to humans; the prick of the crown of thorns causes burning pain, although it is not fatal. Specially trained divers collected the acanthasters into bags with sharp spikes or injected a lethal dose of formaldehyde into the body of the starfish. Only in this way was it possible to pacify the invasion of voracious predators and save the reef. Nowadays, all species of starfish are in a safe condition and do not need protection.

The crown of thorns eats the coral.

They raise many questions, among which the following are of particular interest: “What does a starfish eat?”, “For whom does it pose a mortal threat?”

Stars on the seabed

These extraordinary decorations of the seabed have existed on the planet for quite a long time. They appeared about 450 million years ago. There are up to 1600 types of stars. These animals inhabit almost all seas and oceans of the earth, the water of which is quite salty. Stars do not tolerate desalinated water; they cannot be found in the Azov and Caspian Seas.

Animals can have from 4 to 50 rays, sizes vary from a few centimeters to a meter. The lifespan is about 20 years.

The sea inhabitants do not have a brain, but on every ray there is an eye. The organs of vision resemble insects or crustaceans and distinguish between light and shadow well. Many eyes help animals hunt successfully.

Stars breathe almost through their skin, so it is very important for them to have a sufficient amount of oxygen in the water. Although some species can live at decent depths of the ocean.

Structural features

It is interesting how starfish reproduce and feed. Biology classifies them as invertebrate echinoderms. The starfish does not have blood as such. Instead, the star’s heart pumps sea water enriched with some microelements through its vessels. Pumping water not only saturates the animal's cells, but also by forcing fluid into one place or another helps the star move.

Starfish have a ray structure of the skeleton - rays extend from the central part. The skeleton of sea beauties is unusual. It consists of calcite and develops inside a small star from almost a few calcareous cells. What and how starfish feed largely depends on the characteristics of their structure.

These echinoderms have special pedicellaria on their tentacles in the form of tweezers at each tip of the outgrowth. With their help, the stars hunt and clean their skins from debris clogged between the needles.

Cunning hunters

Many people are interested in how starfish eat. A brief description of the structure of their digestive system can be found below. These amazing beauties create the impression of complete security. In fact, they are sea predators, voracious and insatiable. Their only drawback is their low speed. Therefore, they prefer a stationary delicacy - mollusk shells. The starfish eats scallops with pleasure, and is not averse to eating sea urchins, sea cucumbers, and even fish that carelessly swim too close.

The fact is that the starfish has practically two stomachs, one of which can turn outward. An unwary prey, captured by the pedicellariae, is transferred to the mouth opening in the center of the rays, then the stomach is thrown over it like a net. After this, the hunter can release the prey and slowly digest it. For some time, the fish even drags its executioner along with it, but the victim can no longer escape. Everything that a starfish eats is easily digested in its stomach.

She acts somewhat differently with shells: she slowly approaches the dish she likes, entwines the shell with her rays, places her mouth opening opposite the slit of the shell and begins to move the shells apart.

As soon as even a small gap appears, the external stomach is immediately pushed into it. Now the sea gourmet calmly digests the owner of the shell, turning the mollusk into a jelly-like substance. This fate awaits any eaten victim, no matter whether the starfish feeds on a scallop or a small fish.

Features of the structure of the digestive system

The predator does not have any devices for capturing prey. The mouth, surrounded by a ring lip, connects to the stomach. This organ occupies the entire interior of the disc and is highly flexible. A gap of 0.1 mm is enough to penetrate the shell doors. In the center of the aboral side, a narrow, short intestine opens, extending from the stomach. What a starfish eats largely depends on the unusual structure of its digestive system.

Love of the stars at the bottom of the ocean

Most starfish are heterosexual. During love games, individuals are so busy with each other that they stop hunting and are forced to fast. But this is not fatal, because in one of the stomachs these cunning creatures try to deposit nutrients in advance for the entire duration of mating.

The gonads are located in stars near the base of the rays. When mating, the female and male individuals connect the rays, as if merging in a tender embrace. Most often, eggs and male reproductive cells end up in sea water, where fertilization occurs.

If there is a shortage of certain individuals, stars can change sex to maintain the population in a certain area.

These eggs are most often left to their own devices until the larvae hatch. But some stars turn out to be caring parents: they carry eggs and then larvae on their backs. For this purpose, in certain species of starfish, during mating, special sacs for eggs appear on their backs, which are well washed with water. There she can remain with the parent until the larvae appear.

Reproduction by division

A completely extraordinary ability of starfish is reproduction by fission. The ability to grow a new ray arm exists in almost all animals of this species. A star grabbed by a beam by a predator can throw it away like a lizard's tail. And after a while, grow a new one.

Moreover, if a small particle of the central part remains on the beam, after a certain time a full-fledged starfish will grow from it. Therefore, it is impossible to destroy these predators by cutting them into pieces.

Who are starfish afraid of?

Representatives of this class have few enemies. Nobody wants to mess with the poisonous needles of sea celestials. Animals are also able to secrete odorous substances to scare away particularly voracious predators. In case of danger, the star can bury itself in silt or sand, becoming almost invisible.

Among those who feed on starfish in nature, large seabirds predominate. On the shores of warm seas they become prey for seagulls. In the Pacific Ocean, cheerful sea otters are not averse to feasting on the star.

Predators harm underwater plantations of oysters and scallops - what the starfish eats. Attempts to kill animals by cutting them into pieces led to an increase in the population. Then they began to fight them, bringing the stars ashore and boiling them in boiling water. But there was nowhere to use these remains. There have been attempts to make fertilizer from animals that also repels pests. But this method was not widely used.