Starfish is different. How and what does a starfish eat: features, description and interesting facts. Structure and organ systems of echinoderms

Sea stars

classis Asteroidea de Blainville, 1830

These echinoderms usually have a flattened body, smoothly turning into radial “arms” (5-40), called rays. The shape and structural features of the rays are very diverse: from wide and short, giving the animal pentagonal contours, to thin and long, reminiscent of tentacles. Unlike lilies, the movie star's mouth and ambulacral grooves are located on the lower surface of the body, facing the substrate.


In situations where movie stars have an anus, it, like the madrepore plate of the ambulacral system, is located on the upper (dorsal) surface of the body.
All stars are mobile organisms, moving along the substrate with the help of ambulacral legs located in the ambulacral grooves. Like lilies, movie stars do not have a pronounced anterior-posterior axis and lack any “head end”. Stars are perfect radial animals.
The skeletal plates and spines of movie stars are very diverse, sometimes transforming into special surface organs - pedicillaria. Under a microscope, it is possible to see that the pedicellaria is a group of a number of elongated “bones” that work like scissors or forceps. With these tweezers, stars can clean the surface of the body from various fouling organisms that constantly want to settle on these convenient “hosts”.
Most movie stars are predators and corpse eaters; stars are known to be detritivores and filter feeders. Cannibalism is also common. When capturing a large prey, the star's stomach is capable of turning outward from the mouth opening and enveloping the prey.
The larvae of movie stars are called bipinnaria and brachiolaria, but there are stars with direct development, capable of bearing their young and caring for their offspring. Larvae that are able to feed during their own development in plankton are called planktotrophic, while non-feeding planktonic larvae are called lecithotrophic larvae.
There are now about 1,500 known species of sea movie stars, most of which are inhabitants of tropical seas.
According to our data, 25 species of movie stars live in the waters of Southern Primorye. Let's talk about the most typical and frequently encountered representatives of this class of echinoderms.

Ludia two-needle

Luidia quinaria Martens, 1865 bispinosa Djakonov, 1952

This star has a strongly flattened body with 5 long, narrow rays, pointed at the ends. The span of the rays of the luidia reaches 30 cm. On the superficial (dorsal) side, the central disk and rays of the luidia are dark brown with a violet tint, sometimes almost black, and the lower (ventral) side and sides of the rays are orange-yellow. Along the edges of the rays on the dorsal side, the upper marginal (marginal) plates are clearly visible. The dorsal surface itself is smooth and covered with square-shaped paxillae - groups of small needles sitting on one rod. On the sides of the rays there are large flattened spines and small spines extending from the lower marginal (marginal) plates.
They live on muddy, silty or sandy soils at depths from 3 to 100 m. Luidia have planktotrophic larvae.

Patiria comb

Patiria pectinifera (Mueller et Troschel, 1842)

This star has a wide, flattened disk and very short, wide rays that are pointed at the ends. The dorsal side is somewhat convex, and the ventral side is completely flat. There are usually 5 rays, although 4, 6 and even 7-rayed pathiria are found. The ray span of the largest specimens reaches 18 cm. The color of the pathiria is very variegated: blue with orange and yellow spots on the dorsal side and orange-yellow on the ventral side. The dorsal side of the pathiria is covered with plates overlapping each other like tiles, the free edges of which always face the center of the disk. Patiria received its specific name for the combs of needles located on the ventral side, connected at the base by a soft membrane.
Patiria comb is a low-boreal-subtropical species, found mainly in the regions of Southern Primorye. These stars are very common in the littoral zone among stones and on rocky ground. On sandy, rocky and silty soils, pathiria are found up to a depth of 40 m. They prefer to settle on coarse sandy areas of the bottom mixed with pebbles and large stones with clumps and thickets of zoster and phyllopadex algae. Patiria is a predator that prefers to attack small mollusks.
In the waters of Southern Primorye, patiriyas spawn in the second half of August and early September. Patirium larvae are planktotrophic.

Solaster pacific

Solaster pacificus Djakonov, 1938

These cold-water stars prefer greater depths and are found in Southern Primorye, as a rule, deeper than 60-70 m.
Pacific solasters have a wide disk, slightly convex on the dorsal side, from which 7-8 rays, rounded on the sides and slightly swollen, extend, although other representatives of this genus of stars usually have more than 10 rays. These are large stars with a ray span of up to 30 cm. The central part of the disk and wide stripes along the rays are dark purple in color and stand out sharply against the general orange-red background. The upper (dorsal) surface of the solasters is covered with closely spaced bunches of low needles of different sizes, sitting on common bases – paxillae.
The reproductive characteristics and biology of Pacific solasters have not been sufficiently studied. The larvae are lecithotrophic.

Henricia Hayashi

Henricia hayashi Djakonov, 1961

The taxonomy of the genus Henrici is very difficult due to large quantity species and great species variability of these stars, especially Pacific representatives, so we do not present a photo of the starfish. For the northwestern part Pacific Ocean 28 species of Henricia were noted, of which 7 species were recorded for Peter the Great Bay in Southern Primorye. Henricias live at depths from several tens to several hundred meters.
Henricia are 5-rayed, thin stars, with a dorsal surface rough to the touch, characterized by a reticulated, looped microrelief on a relatively small central disk and rounded rays. In rare cases, 6-rayed stars are found. Lifetime coloration of Henricia is usually red, red brick, or orange.
We identified Henricia Hayashi as the shallowest-water species, living only in the Sea of ​​Japan and found in Southern Primorye at depths of 25 to 45 meters on rocky soils, while other coastal Henricias are usually found deeper than 40 m. The ray span of Henricia Hayashi is up to 10 cm.
The peculiarities of the biology of Henricia are very interesting, namely, the manifestation of care for the offspring. All species of this genus are viviparous and do not have free-swimming planktonic larvae. Before laying eggs, the female attaches her rays to underwater objects and raises the rest of the rays and the central disk, forming something like a bell. Eggs are laid in this enclosed space and develop in balls near the mouth (or even in the mother's mouth) into a lecithotrophic larval stage and then into a small star. All this time (usually up to 3 weeks), mother Henricia maintains her position and does not eat.

Lysastrosoma antisticta

Lysastrosoma anthosticta Fisher, 1922

This 5-rayed star is easily distinguishable from all others by the “loose”, soft consistency of the body, devoid of the elasticity characteristic of stars, as can be seen in the photograph. The softness of the dorsal cover is explained by the fact that the lysastrosome skeleton plates are located very loosely and are not connected to each other into a single shell. The dorsal surface is uneven and lumpy with thin, sparsely spaced spines. The upper marginal (marginal) plates are widely spaced and connected by chains of small plates. On the lower marginal (marginal) plates on the sides of the rays there are long needles, covered with a soft sheath, to which a bunch of cruciform pedicillariae is attached.
The span of the lysastrosome rays reaches 22 cm. The dorsal side is red or dark crimson with a prominent yellow madrepore plate. The lower (ventral) side is light orange.
This species is very widespread in Southern Primorye, occurring in the littoral zone and at shallow depths on a variety of soils: sand, rocky deposits, muddy substrates, among boulders and in algae thickets. Lysastrosomes are predators that attack mollusks, crustaceans and other echinoderms, including sea urchins. The larvae are planktotrophic.

Distolasteria causticus

Distolasterias nipon (Doderlein, 1902)

A very large star with a ray span of up to 45 cm, as can be seen in the photo, often found in Southern Primorye at depths from 2 to 50 m. Usually 5 long strong rays extend from the small central disk, tapering at the ends. The skeletal plates on the dorsal side are arranged in longitudinal rows and each of them is armed with a strong conical needle. The upper and lower marginal plates also bear long, blunt spines. All needles are surrounded by a thick ridge of cruciform pedicillariae.
Dystolasteria is very beautiful stars: on the back they are velvety black with large bright yellow needles and an orange madrepore plate, and the ventral side is light yellow. They prefer silty soils. Predators. Spawning occurs in late May - early July. The larvae are planktotrophic.

Letasteria black (photo)

Lethasterias fusca Djakonov, 1931

This seaside 5-rayed star is easily distinguished by the black or almost black color of the central disk and rays on the dorsal side. Dark gray letasteria are also found, and on the rays against a dark background there may be yellowish and whitish spots, sometimes arranged in the form of bands. The span of the rays reaches 23 cm. The rays are blunt at the ends, and along the middle of their dorsal side there is a row of wide needles, at the top of which there are small spines.
Letasteria live on rocky reefs and rocky soils at shallow depths (2-50 m). Less common on silty sands mixed with pebbles and stones. Juveniles are found on thalli of macrophyte algae. Lead predatory image life, attacking small shellfish, and is often found in oyster beds or on mussel banks. The larvae are planktotrophic.

Aphelasterias japonica Bell, 1881

Distinctive feature This small seaside star has narrow constrictions that lace long, relatively thick, but easily broken off rays from the small central disk. The scope of the rays, and these stars have 5 of them, is up to 24 cm. The plates of the dorsal skeleton and the spines of aphelasteria are arranged in transverse rows - combs. The dorsal side is bright crimson, often mixed with purple hues. The tips of the needles and the ventral side are whitish.
Japanese letasteria are quite common in the littoral zone in the area of ​​stone reefs and capes, and are also found on rocky soils to depths of 40-50 m. They are less common on silted sand mixed with pebbles and stones, and on shell rocks. They make seasonal migrations. They lead a predatory lifestyle, attacking mainly small mollusks. In Southern Primorye, afelasteria spawn in August-September. The larvae are planktotrophic.

Euasteria spinosa

Evasterias echinosoma Fisher, 1926

Spiny elasteria is the largest starfish not only in Primorye, but also in all Far Eastern seas Russia. The span of the rays of these huge stars reaches 80 cm. There are always 5 rays, they are long, thick, with rounded sides, with short, strong, blunt needles on the dorsal plates. The plates with needles are located along the rays in regular longitudinal rows. Around the needles are bundles of cruciform grasping pedicillariae. It is very easy to verify their presence and grip - place the outer part of your palm on the star and the pedicillaria will instantly grab the hairs on your hand.
The dorsal side is dark red with a crimson tint. It lives at shallow depths (5-100 m), where it is usually confined to sandy soils mixed with pebbles and silt. Less common on clean mud or rocks. A predator that can cope with almost all mollusks and other echinoderms. The larvae are planktotrophic.

Evasteria reticularis

Evasterias retifera f. tabulata Djakonov, 1938

Reticulate easteria are smaller representatives of this genus, but their ray span reaches 40 cm. Perhaps these are the most beautiful stars of the Far Eastern seas - against a crimson background there are turquoise-blue mushroom-shaped needles, collected in groups and forming a wide-loop network. The madrepore plate and ventral side are orange. Bizarre and bright patterns on the dorsal surface gave these eusteria their species name – reticulata.
These stars are found from the littoral zone to shallow (40 m) depths and are usually confined to sandy soils mixed with stones. At low tide, medium-sized reticulated elasteria are found among stones and boulders. Predators. The larvae are planktotrophic.

Common Amur star

Asterias amurensis Lutken, 1871

The most common and frequently encountered starfish in Southern Primorye. Asteria have a wide central disk, from which extend 5 wide, flattened, with thin, almost sharp, lateral edges, pointed at the ends of rays, the span of which is about large forms reaches 30 cm. The ventral side is very flat. The dorsal needles are small, usually bluntly cone-shaped, single. The largest of them are sometimes located along the midline of the beam. The color is very variable, ranging from ocher to dark purple, but yellowish-brown, sometimes pinkish-brown forms predominate. They are found in the littoral zone to depths of 30-40 m, and are rare deeper. They prefer sandy and rocky soils. In the littoral zone they are found among stones and algae thickets. On large algae thalli, juvenile asteria form huge accumulations (“kindergartens”), covering the surface of macrophytes with small beads. Large asteria are not uncommon in bays that are highly polluted by humans, where other types of stars no longer survive.
Amur stars are predators that attack mollusks (scallops, oysters, mussels) and other echinoderms, and are carrion eaters. In places of large concentrations, cannibalism is often observed. Sometimes under water you can observe peculiar “balls” of many asteria, clinging to the victim with their inverted stomachs.
Of the peculiarities of the biology of asteria, their symbiosis is interesting ( mutually beneficial cohabitation) with arctonoe polychaete worms (Arctonoe vittata) living in the ambulacral grooves of the star. The worm receives the remains of the predator's food, and in turn eats numerous epibionts (fouling organisms) from the surface of the star, acting as a cleaner.
In Southern Primorye, the spawning period of asteria is extended and usually consists of two stages: June-July and September. Amur asteria form dense spawning aggregations. The spawning behavior of these stars is interesting. Females rise above the ground on the rays and their reproductive products accumulate between the rays in the form of small (2-3 cm) orangish mounds. Males crawl around spawning females, slightly lifting central part and sweep out their reproductive products white. Then the stars of both sexes begin to crawl in the spawning areas, simultaneously mixing the sexual products and protecting them from juvenile fish and various crustaceans. This type of behavior can also be called caring for offspring. The larva of Asteria is planktotrophic.

And finally, how does a starfish walk?

Starfish are one of the most beautiful and mysterious sea creatures. These animals add extraordinary beauty to the seas and oceans. For the first time so unusual sea ​​creatures appeared more than 450 million years ago.

Starfish belong to the class of invertebrates and the phylum Echinodermata. They are very diverse not only in their colors, but also in shape. Today there are more than 1,600 species of starfish. Their close relatives are snaketails, luxurious sea ​​lilies, holothurians, as well as unusual sea ​​urchins.

Basic distinctive feature The difference between starfish and their relatives is their body shape. The body has the shape of a star, which is divided into 5 symmetrical sectors. However, among these graceful animals there are organisms that are endowed big amount sectors. In some individuals, their number can vary from 6 to 12, and sometimes even from 45 to 50.

The colors of these amazing sea creatures include almost the entire color gamut, but, in most cases, you can find shades of red, less often brown, blue, purple, pink, yellow and black. There are also pale starfish, but they usually live on the bottom of the sea or ocean, while bright ones live in shallow water.

At first, starfish may seem like primitive creatures, because they lack sense organs, a brain, and are also poorly divided internal organs, but such simplicity is nothing more than deception.

It is important to note that this type of invertebrate has an internal skeleton. Despite the fact that sea stars do not have a backbone, they have a huge number of calcareous plates that are connected to each other together.

In a young individual, the skeletal components are hidden under the skin, but after a certain period of time the skin wears off and the spines become visible from the outside. These spines give starfish their prickly appearance.

There is also another component that affects appearance these beautiful sea creatures are pedicillaria. Pedicillaria are modified needles, similar to tiny tweezers. They play an important role in the life of the starfish. Thanks to tweezers, they clean the upper side of their body from various debris and sand.

Starfish have an underdeveloped muscular system. However, they have a special system - ambulacral, which consists of cavities and channels woven together. Thanks to this system, starfish pump liquid from one part to another. When pumping liquid, parts of its body begin to wriggle and move.

It is important to note that these beautiful animals still have sense organs. These include the eyes located at the ends of each sector. The eyes are very primitive and can only distinguish between light and darkness, these are luxurious objects Marine life unable to see. They only catch chemical substances, only each of them feels them differently. Starfish have a well-developed sense of touch, which tells them whether they are encountering a prey or a predator.

They also have a well developed digestive system. The mouth of these unusually beautiful animals is located in the middle of the disc on the underside, and the small anus is located on the dorsal side of the body. The stomach of sea stars is endowed with outgrowths in which food reserves are accumulated in case of starvation. And starvation occurs regularly in starfish, because during the breeding season they stop eating food. The stomach of such an animal can stretch like rubber, taking various shapes. Thanks to this stretching of the stomach, sea beauties are able to digest prey whose parameters exceed their own size several times. There is a known fact when a species of starfish, Luidia, ate a huge sea urchin to such an extent that after eating such food, she died because she could not get rid of its remains.

Sea beauties are found in almost all seas and oceans. However, in warm waters The variety of starfish is much higher than in cold ones. Most of them live in shallow water, but there are also those that prefer to be in depth.

Initially, starfish may seem helpless, but this is far from the case. They are formidable predators. These delightful sea creatures are insatiable and never miss an opportunity to eat. The exception is the breeding season. Silt, or rather their mined particles, feed only on those species that live on the bottom of the sea or ocean. Conditionally, “non-predators” include culcites, which feed on growths on corals. The remaining species hunt for other prey.

Most starfish are unpretentious eaters; they eat everything they can hold with their rays until their stomach stretches, not even disdaining carrion. Certain species feed only on a different type of food: corals, gastropods and sponges.

The favorite food of sea stars are sedentary animals - bivalves and sea urchins. They chase the sea urchin crawling, after they have caught up with it, they begin to eat it with their mouth. Bivalves They have a shell, the valves of which close very tightly in case of any danger. For this reason, these shellfish are treated differently by starfish. At first, the starfish clings with its rays to the shell flaps and only after that begins to open them.

Like most representatives of fauna, starfish are heterosexual. But there are also species that have both female and male genital organs at the same time. They are located at the base of the rays in pairs.

Reproduction of starfish occurs both sexually and asexually. Basically, such reproduction occurs only in multirayed species. The starfish's body is divided into two parts, after which each of them multiplies the rays that are missing. All other animals asexual reproduction is possible only in case of recovery from damage to the body. One beam is enough for regeneration, however mandatory element for restoration is the presence of a piece of the central disk.

As a rule, these amazing sea animals have practically no enemies, because the spines, which may contain poison, repel more large predators. Moreover, starfish, sensing approaching danger, bury themselves in the sand so as not to attract the attention of a predator.

People have noticed these unusual, original animals in shallow water for a very long time. However, starfish did not arouse any economic interest for them. Only in China some people take it as food, but at the same time feed pets starfish No one dared, since after eating the treat, the pets could die. This is most likely due to toxins that accumulate in certain types with eating various corals and poisonous shellfish. But with the prosperity of the maritime economy, starfish began to be considered enemies. It later turned out that these animals very often ate bait intended in crab traps, and also made invasions on plantations where scallops and oysters were bred. At one time, these sea ​​predators they tried to eradicate them by cutting them into pieces. But this only increased their number, because from each piece a new starfish appeared. Over time, they learned to catch them using special trawls, after which the starfish were killed with boiling water.

Sunflower starfish, or pycnopodia (lat. Pycnopodia helianthoides) is the largest and fastest starfish in the world. This giant, with two dozen tentacles, growing up to one meter in diameter, lives in the northeastern waters of the Pacific Ocean, from the Aleutian Islands to the California coast.

Pycnopodia, despite its impressive size, are very active and mobile creatures, as well as experienced hunters. Their favorite prey is sea urchins, which they catch with tenacious tentacles that are almost as dexterous as the hands of octopuses. In the excitement of the chase, the pycnopodia develops a speed of 1 m/min, covering a space of 0.5 sq.m. with its body. At the same time, 15 thousand small legs, densely studded with suction cups, sway under her body.

This entire arsenal of the predator turns the starfish into a real killing machine, leaving the victim no chance of salvation. She swallows the sea fish whole, and after having lunch, spits out the shell, completely devoid of needles.

In addition to hedgehogs, pycnopodia just as easily deal with hermit crabs, weakened fish, and snails. If the prey is too large, the predator simply opens its mouth wider, and if this does not help, it pushes its stomach out and digests the prey on the spot.

Finding itself at the prey site, the pycnopodium, forced to flee, sheds part of its tentacles. However, this is no reason to worry - new ones will grow in just a few weeks.

Sunflower starfish can be different colors, from bright orange, red and yellow to brown or purple. Large specimens weigh more than 4.5 kilograms, and the number of tentacles varies from 16 to 24.

The underwater world is full of diversity. Among others, special attention is paid to the animals that live on the bottom - starfish. They can be different forms and flowers. To talk about the most interesting types we have created a selection of 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 Sponge Bob, so many people consider these crested ones to be exclusively Pink colour and perfectly proportional. Of course wild nature much more diverse, it offers other shades and shapes.

Among the most beautiful starfish in the world you will notice even those whom by eye you would never classify as similar type. 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 East Coast North America, where they can be found on the beaches without any problems. 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 point is that in English language biscuit - means exactly 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 coral reefs, because they are her favorite food. Voracity allows this predator to destroy two square meters polyps in just one day, enveloping each of them with his body, and then dissolving 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 Indian Ocean 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 type notable for the fact that it can be found in cold waters in the area Sea of ​​Okhotsk. 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 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.

Water Dweller South-East Asia will amaze you with the number of shades present in the 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.

Sea stars- These are very unusual animals that live in the seas and oceans. They are invertebrates, belong to the phylum echinoderms and are very similar to stars, as they have rays diverging in different directions. Most often, the sea star has five rays, but there are species with three, four and six rays. The color of the body is often very bright and varied; on the surface there are special hard plates with needles or spines. The sizes of stars vary greatly and can range from 2 cm to 100 cm, but most stars have a diameter of about 20 cm.

Spreading

Starfish are widely distributed across to the globe. They can be found in all oceans and seas and in all climatic zones, but in warm waters there are more starfish than in cold waters, and in fresh waters they are not found at all.

These animals prefer a bottom lifestyle, often live in shallow water, but can also live at depth, but not deeper than 8.5 km.

Now on earth there are 1.6 thousand species of starfish.

Nutrition

Almost all starfish are predators. They mainly feed on marine invertebrates - worms, mollusks, sponges, barnacles, corals and others. Some deep-sea starfish feed on the mud they find on the bottom.

The digestive system of starfish is quite unique. Their mouth opening is located on the ventral side, and two stomachs extend from it. One stomach has the ability to turn outward and envelop the victim, and the second stomach has ten processes that are located inside the rays of the starfish. This unusual digestive system allows the star to eat prey that is larger than itself.

Lifestyle

Starfish are slow, sedentary animals. They usually crawl lazily along the bottom, lie still, or may climb rocks and corals in search of prey. Their movement speed is very low - 10-30 cm per minute. Stars are considered animals leading sedentary image life. As a rule, they move no further than 0.5 km from their usual place of residence.

In their development, stars go through several stages of development. From the eggs that adults throw into the water, larvae are first formed and then they gradually turn into an adult starfish. Some species of starfish carry larvae in special brood pouches on their bodies.

Starfish can live 20 years or more.

• Starfish don't have a brain.
• Instead of eyes, starfish have light-sensitive cells located at the tips of their rays.
• Starfish are capable of regeneration - from a detached ray, a new star can develop.

Brief information about starfish.