10 Facts About Starfish (Sea Stars) 10 Facts About Starfish (Sea Stars) 10 Facts About Starfish (Sea Stars) Learn About This Popular Echinoderm By Jennifer Kennedy Updated April 25, 2016. Starfish (sea stars) are beautiful animals that can be a variety of colors, shapes and sizes, although all resemble a star. While some appear smooth, they all have spines covering their upper surface and a soft underside. If you gently turn over a live sea star, you'll see its tube feet wiggling back at you. These iconic marine animals are fascinating creatures. Learn more about them below. Jeff Rotman/The Image Bank/Getty Images • Sea stars are not fish. Although sea stars live underwater and are commonly called " starfish ," they are not fish. They do not have gills, scales, or fins like fish do and they move quite differently from fish. While fish propel themselves with their tails, sea stars have tiny tube feet to help them move along (see more on that below). continue reading below our video Test Your General Science Knowledge Starfish and purple sea urchin. Kathi Moore / EyeEm / Getty Images • Sea stars are Echinoderms.

Sea stars belong to the Phylum Echinodermata . That means they are related to sand dollars (yes, they are a real animal), sea urchins , and sea cucumbers . All echinoderms have five-point radial symmetry , which means that their body plan has five sections (or multiples thereof) arranged around a central disk. Next time you're in a beach-themed store, see if you can find a dried sea star, sand dollar and sea urchin and find the 5 sections in each. More » Colorful sea star in the Galapagos. Ed Robinson / Getty Images • There are thousands of sea star species. There are about 2,000 species of sea stars. Some live in the intertidal zone , some in deep water , some in tropical areas, some in cold water. Sun star with many arms. Joe Dovala / Getty Images • Not all sea stars have 5 arms. While the five-armed varieties of sea star are the most well known, not all sea stars have 5 arms. Some have many more. Take the sun star for instance, which has up to 40 arms! Sea star regenerating four arms.

Daniela Dirscherl / Getty Images • Sea stars can regenerate a lost arm. Amazingly, sea stars can regenerate lost arms . This is useful if the sea star is threatened by a predator - it can drop an arm, get away and grow a new arm. Sea stars house most of their vital organs in their arms, so some can even regenerate an entirely new sea star from just one arm and a portion of the star's central disc. It won't happen too quickly, though. It takes about a year for an arm to grow back. More » Crown-of-Thorns Starfish (Acanthaster planci) on Coral Reef, Phi Phi Islands, Thailand. Borut Furlan / WaterFrame / Getty Images • Sea stars are protected by armor. Depending on the species, a sea star's skin may feel leathery, or slightly prickly. Sea stars have a tough covering on their upper side, which is made up of plates of calcium carbonate with tiny spines on their surface. A sea star's spines are used for protection from predators, which include birds, fish and sea otters . One very spiny sea star is the crown-of-thorns starfish, which is shown here.

More » Closeup of the arms of a sea star under a pier, showing its tube feet. Courtesy pfly , Flickr • Sea stars do not have blood. Instead of blood, sea stars have a water vascular system , in which the sea star pumps sea water through its sieve plate, or madreporite , into its tube feet to extend them. Muscles within the tube feet retract them. Tube Feet of Spiny Starfish. Borut Furlan / Getty Images • Sea stars move using their tube feet. Sea stars move using hundreds of tube feet, which are located on their underside. The tube feet are filled with sea water, which the sea star brings in through the sieve plate, or madreporite, on its top side. Sea stars can move more quickly than you might expect. If you ever get a chance, try visiting a tide pool or aquarium and take a moment to watch a sea star moving around. The sea star's tube feet also help the sea star hold its prey , which includes bivalves like clams and mussels. More » Sea star eating a bivalve. Karen Gowlett-Holmes / Getty Images • Sea stars eat with their stomachs inside-out.

Speaking of prey, sea stars have a rather unique way of eating theirs. A sea star's mouth is on its underside. They prey on bivalves like mussels and clams, as well as small fish, snails, and barnacles. If you've ever tried to pry the shell of a clam or mussel open, you know how difficult it is. Sea stars wrap their arms around the animal's shell and pull it open just enough. And then it does something we could never imagine - it pushes its stomach through its mouth and into the bivalve's shell. It then digests the animal and slides its stomach back into its own body. This unique feeding mechanism allows the sea star to eat larger prey than it would otherwise be able to fit into its tiny mouth. Common Sea Star (visible eye spots circled). Paul Kay / Getty Images • Sea stars have eyes. While they can't see as well as we do, sea stars have an eye spot at the end of each arm. This is a very simple eye that looks like a red spot. The eye doesn't see much detail, but can sense light and dark. More » Starfish Facts, Information and Worksheets | Teaching Resources This worksheet has a free sample available.

Download the sample here » Download This Sample This sample is exclusively for KidsKonnect Basic members! To download this worksheet, click the button below to signup for free (it only takes a minute) and you'll be brought right back to this page to start the download! Already a member? Log in to download. Starfish are echinoderms (spiny skinned sea urchins). They are also known as sea stars and are not really fish despite the name been given to them. Starfish cannot swim, and they do not use gills to breathe. For more information on these interesting sea urchins, see the fact sheet below or download the complete worksheet pack. There are over 2,000 species of starfish. All echinoderms have five-point radial symmetry, which means that their body plan has five sections arranged around a central disk. Starfish are found in the deep blue sea of the ocean and shallow water as well. They are found in every ocean of the world. They are never found in fresh water. Most starfish have a spiky shell which offers them protection. Depending on the species, a sea star’s skin may feel leathery, or slightly prickly.

This tough covering on their upper side is made up of plates of calcium carbonate with tiny spines on their surface. A sea star’s spines are used for protection from predators, which include fish, sea otters and birds. Starfish come in a variety of colors and have many different types of patterns. While the five-armed varieties of sea star are the most well known, not all sea stars have 5 arms. Some have many more. Take the sun star for instance, which has up to 40 arms. The Coscinasterias Calamaria also known as the eleven-armed sea star has an armspread that can go up to 30 cm. As the name suggests, it does have eleven arms but there are times when the number can go up to 14. Amazingly, sea stars can regenerate lost arms. This is useful if the sea star is threatened by a predator. The starfish can drop an arm to get away. Sea stars house most of their vital organs in their arms, so some can even regenerate an entirely new sea star from just one arm and a portion of the star’s central disc. It takes almost a year for this to happen.

Starfish have hundreds of tiny projections known as tube feet on the underside of their body. The tube feet allow the starfish to move along the ocean bottom and open upon the scallops and clams they hunt for food. The starfish has two stomachs. The cardiac stomach eats the food outside the starfish’s body. When the cardiac stomach comes back into the body, the food in it is transferred to the pyloric stomach. After the tube feet open the shell of its prey, the cardiac stomach is extended into the shell to pull the food inside. The tube feet play an important role in helping the starfish to procure its food. The tube feet are used to open up the oysters or clams. Then the stomach is extended into the shell to pull the food inside. They prey on bivalves like mussels and clams, as well as small fish, snails, and barnacles. Instead of blood, sea stars have a water vascular system, in which the sea star pumps sea water through its sieve plate, or madreporite, into its tube feet to extend them. Muscles within the tube feet retract them.

The starfish have microscopic eyes at the end of each arm; this enables the starfish to view movement and differentiate between light and dark. They don’t, however, see much detail. Starfish Worksheets This bundle includes 12 ready-to-use Starfish worksheets that are perfect for students to learn about Starfish also known as sea stars and are not really fish despite the name been given to them. Starfish cannot swim, and they do not use gills to breathe. This download includes the following worksheets: Introduction Sea Stars are not Fish Research Activity Starfish (Sea Stars), Starfish (Sea Star) Pictures, Starfish (Sea Star) Facts - National Geographic Size relative to a tea cup Please add a "relative" entry to your dictionary. Marine scientists have undertaken the difficult task of replacing the beloved starfish’s common name with sea star because, well, the starfish is not a fish. It’s an echinoderm, closely related to sea urchins and sand dollars. There are some 2,000 species of sea star living in all the world’s oceans, from tropical habitats to the cold seafloor.

The five-arm varieties are the most common, hence their name, but species with 10, 20, and even 40 arms exist. They have bony, calcified skin, which protects them from most predators, and many wear striking colors that camouflage them or scare off potential attackers. Purely marine animals, there are no freshwater sea stars, and only a few live in brackish water. Beyond their distinctive shape, sea stars are famous for their ability to regenerate limbs, and in some cases, entire bodies. They accomplish this by housing most or all of their vital organs in their arms. Some require the central body to be intact to regenerate, but a few species can grow an entirely new sea star just from a portion of a severed limb. Most sea stars also have the remarkable ability to consume prey outside their bodies. Using tiny, suction-cupped tube feet, they pry open clams or oysters, and their sack-like cardiac stomach emerges from their mouth and oozes inside the shell. The stomach then envelops the prey to digest it, and finally withdraws back into the body.

19 bizarre and beautiful starfish species | MNN - Mother Nature Network 19 bizarre and beautiful starfish species Who knew that starfish could come in so many shapes and colors ... and with so many arms! Photo: Ethan Daniels /Shutterstock Starfish, or more technically accurate, sea stars, are fascinating creatures and amazingly diverse. Most commonly thought of as a five-armed intertidal species, starfish come in myriad shapes, sizes, colors, arm counts, and are found from shorelines to the deep sea. And while they seem like docile creatures, they can actually be voracious and rather savage predators. Here are some of the many beautiful, odd and surprising species of sea stars around the world. Leather star (Dermasterias imbricata):Found along the west coast of North America, from Alaska to Mexico, the leather star lives in the intertidal zone down to depths of about 300 feet where it dines on everything from algae to sponges to sea cucumbers. Meanwhile, it does its best to avoid the morning sun star, another species of sea star that makes a quick meal (well, relatively speaking) of the leather star.

Leather stars make up to 50% of the diet of the morning sun star. Photo: Ed Bierman /Flickr *** Morning sun star (Solaster dawsoni): And here is that voracious predator. With anywhere from 8 to 16 arms and usually red or orange coloring, the morning sun star looks, well, like a cartoon sun. It is found in the northern Pacific , from Japan to Siberia and down the coast of North America down to California. Other sea stars literally run away from it if they're touched by it. Some, however, fight back, including the velcro star and rainbow star which can pinch the morning sun star to make it recoil and provide a window for escape. Others have defense mechanisms -- the slime star inflates itself and exudes a noxious mucus, and the sunflower sea star can detach an arm in order to get away. If a morning sun star can't catch a star of a different species, it has no problem chowing down on an individual of its own species.

Photo: NatureDiver /Shutterstock *** Sunflower star (Pycnopodia helianthoides): The sunflower star is the largest sea star in the world, reaching an armspan of 3.3 feet. That space is taken up by 16-24 arms. They're found along the coast of North America, from Alaska to California, but they're largest in the northern areas. They dine on sea urchins , clams and snails and are usually found in subtidal areas where there is always water, since they can't support their bodies out of water. Photo: Ethan Daniels /Shutterstock *** Pink short spined star (Pisaster brevispinus): Even starfish look pretty in pink. This sea star can reach a whopping two feet in diameter, and can weigh up to two pounds. It dines on clams and sand dollars, so is usually found on sand or mud, but its soft texture allows it to also grip on coral and rocks where it can feast on mussels, tube worms and barnacles. This is also a celebrity species: Spongebob Squarepants' neighbor Patrick Star is a pink starfish. So next time you see one, ask for an autograph.

Photo: jkirkhart35 /Wikipedia *** Granulated sea star (Choriaster granulatus): This species goes by many names, including the cushion sea star or doughboy star, for obvious reasons. The plump starfish is found in shallow waters on coral reefs and rubble slopes where it feeds on algae, coral polyps, and scavenges on dead animals. Photo: Ethan Daniels /Shutterstock *** Royal starfish (Astropecten articulatus): This vividly colored species is found along the east coast of North America, primarily in the southeast. While it can live at depths of up to 700 feet, it mostly hangs out at around 70-100 feet deep where it dines on mollusks. Unlike many other species of starfish, the royal starfish eats its prey whole. Photo: TheMargue /wikipedia *** Bat sea star (Asterina miniata): This fascinating species is called the bat star because of the webbing between its arms, which (so some say) look like bat wings. It is found along the west coast of North America, from Alaska to Baja.

While the species usually has five arms, it can have up to nine, and it can be a wide range of colors from green to orange to purple. So if you're wondering if you're looking at a bat sea star, check if it has the tell-tale webbing. Photo: stevehullphotography /Shutterstock *** Crown-of-thorns starfish (Acanthaster planci): The name of this species is fairly clear. The spines covering its upper surface make it look like, well, you know. Those spines are also venomous, which aid it in its quest for world domination. Found over a wide range in subtropical waters, from the Red Sea to across the Indian Ocean, and across the Pacific Ocean to the western coast of Central America, this species preys on coral polyps. As one of the largest starfish in the world, it has a voracious appetitive. When numbers are low, crown-of-thorns starfish help boost the biodiversity of coral reefs by preying on the fastest growing coral species. But if their populations become too high, they can wreak havoc on coral reefs .

Their population booms are due in part from human fishing of and collection of their natural predators, the humphead wrasse and triton snail. Photo: Ethan Daniels /Shutterstock *** Pacific blood star (Henricia leviuscula): Despite the creepy name, this common starfish is actually a very small, slender species that feeds on sponges and bacteria. Meanwhile, its main predators are birds and humans. They are among the most brightly colored sea star species in the intertidal zone and are found at depths of over 1,000 feet. Photo: Medtrails /wikipedia *** Egyptian sea star (Gomophia egyptiaca): Found along the coasts of eastern Africa and Madagascar, this spiky sea star stays at depths of around 20-25 feet. Like may starfish, it can regenerate parts of its body that are damaged. But with those spikes, it doesn't look like a sea star you want to reach out and mess with.

Alexander Vasenin /wikipedia *** Nine-armed Sea Star (Luidia senegalensis): It may not be the only sea star to have nine arms, but it's the only species to be named for the fact that it has nine arms. Found in the western Atlantic ocean , this starfish, like many species, everts its stomach to engulf its prey, and essentially "swallows" with its stomach. The nine-arm sea star dines on mollusks, small crustaceans, and sea worms, as well as filters stomachfuls of sediment to feast on tiny organisms. Photo: Andrea Westmoreland /Flickr *** Brisingid sea star: Skipping a specific species, these sea stars are so cool, we're highlighting the entire order! The 70 or so species within this order live in the deep sea, at depths between 330 feet to over 19,000 feet below. They are suspension feeders, using their arms, which number from six to 16, to filter water and capture food as it drifts by. They look almost more like a seaweed or coral than a sea star.

Photo: NOAA /Flickr *** Necklace Starfish (Fromia monilis): This jewel-like starfish is found in the Indian Ocean and western Pacific Ocean. Found in shallow water in rocky areas, it feeds on sponges and small invertebrates. It can get as large as 12 inches across, and has unusual and beguiling coloring. That plus its relative hardiness makes it a favorite for people who keep salt water aquariums. It is also called the red tile starfish for obvious reasons. Photo: Hectonichus /wikipedia *** Giant spined star (Pisaster giganteus): This bedazzled sea star is found on the western coast of North America, from southern California up to British Columbia. Found in rocky areas along the low tide mark, they feast on mollusks. This species can grow as huge as two feet in diameter, hence the name that includes "giganteus". Though they have few predators, they are prey items for sea otters and birds.

Photo: Ed Bierman /Flickr *** Pincushion starfish (Culcita novaeguineae): Found in tropical waters of the Indo-Pacific, this unusual species of starfish creates its own little habitat by providing shelter for small shrimp that hide under it, and copepods that live on its outside. Even a species of fish, the star pearlfish, may make itself at home inside the body cavity of the pincushion star, emerging to feed. It would be hard to guess by glancing at it that it is a starfish at all, and not a type of coral! Photo: Ethan Daniels /Shutterstock *** Chocolate Chip Sea Star (Protoreaster nodosus): Mmmmm, chocolate chip cookies! Well, while this looks like a chocolate chip-studded starfish, it wouldn't exactly taste great. The dark nubs are a way for it to look more dangerous, and it works as it has few predators. Because of this, the sea stars actually provide a home on its surface for other species such as shrimp, tiny brittle stars, and juvenile filefish. Though it has few oceanic predators, it does have one serious predator -- humans.

This species is collected as a tourist trinket and for the aquarium trade and are being overharvested in some areas. Photo: Ethan Daniels /Shutterstock *** Blue sea star (Linckia laevigata): This gorgeous blue sea star is found in the tropical waters of the Indian and Pacific Oceans, usually in shallow and sunny parts of reefs and reef fringes. It is a scavenger, and so acts as the clean up crew by feeding on dead animals. Like the chocolate chip sea star, the blue sea star has been part of the sea-shell trade for a long time, its skeleton sold as decoration. Because of this, the populations in some regions have seen dramatic decline. Photo: Ethan Daniels /Shutterstock *** Australian southern sand star (Luidia australiae): The mottled coloring of this species helps tp camouflage it in the sediment of seagrass beds of the Pacific Ocean around Australia and New Zealand. Typically sporting seven arms, it grows to be around 16 inches in diameter. It is sometimes found washed up on the beach after storms. Photo: Dusan Wolczko /shutterstock *** Panamic cushion star (Pentaceraster cumingi): Talk about gorgeous.

This beautiful species is found around the Gulf of Panama and the Pearl Islands, all the way up to the northern parts of the Pacific Ocean. Appropriately, it is also called a knobby star. They can reach up to 18 inches in diameter, and feast on mussels and barnacles. They are considered a keystone species in tidepools thanks to the work they do to keep mussel populations under control. But it's not without effort -- it can take a starfish upwards of six hours to eat a single mussel. Starfish Facts ~ Starfish FAQ “How inappropriate to call this planet "Earth," when it is clearly "Ocean.” ― Arthur C. Clarke Starfish Facts ~ Starfish FAQ What is the widest starfish? The Giant Sea Star is the widest, reaching up to 3 feet in diameter. Largest Starfish Giant sea star What is the heaviest starfish? Thromidia gigas (only name for it) can reach 13 lbs, so it’s the heaviest starfish in the world. Heaviest Starfish Thromidia gigas (From Dave Lane on the Santo 2006 Expedition ) What is the smallest starfish?

Patiriella parvivipara are less than half an inch. Do starfish have eyes? They have a primitive eyes called an eyespot. Eyespots were the the predecessors to our complex eyes. Eyespots can only discern light and dark and on the starfish, they are located on the tip of each leg. Look carefully at the tip of a leg and you might notice a red or black dot- that is the eyespot. Starfish are Echinoderms They are related to sand dollars, sea urchins, and sea cucumbers. Are there freshwater starfish? No. Like Octopuses , they are only found in sea water. How many species of starfish are there? 1,800 Do starfish have any blood? No. They rely on seawater to pump up their legs. What’s the plural of starfish? Starfish What do starfish eat? Anything they can catch but mainly clams, mollusks, some coral and dying fish. They eat clams and other shelled creatures by prying the shell open and then inserting their stomach to digest the critter on the spot. Why do starfish lose their arms?

When they are threatened or grabbed by a predator, such as a crab they will sacrifice the arm that’s being grabbed or simply drop one as a distraction while they try to escape. How long does it take a starfish to regenerate a lost arm? About a year. What happens to the lost arm if it is not eaten or damaged? It can grow into a new starfish as long as some part of the central ring is included. Are starfish poisonous? Yes. There are many species of starfish that are poisonous and even deadly to humans. The crown of thorns, the sun star, the spiny sun star and the leather star are some of them. Their spines are the poisonous parts. Deadliest Starfish – Crown of Thorns starfish What’s another name for starfish? Sea star Do starfish have a front or back? No. Do starfish have brains? They do no not have a centralized brain but instead a network of nerves that simply reacts to its environment. The central nervous system of a starfish consists of a radial nerve running the length of each ray and a circumoral (“around the mouth”) nerve ring that connects the radial nerves.

Contrary to what you might expect, the nerve ring doesn’t seem equipped to do any kind of processing of information. Instead, all the sensory information must go to the radial nerves, any memories must be stored in the radial nerves, and any decisions about what to do must be made in the radial nerves. And somehow, the five different radial nerves must coordinate those decisions if the starfish is going to get anywhere. The best theory is that some sensory information is shared between the different rays (it is unclear how much, or how far it goes), and that the rays can inhibit each other — that is, one ray can take charge of the whole starfish for a time. When moving, this seems likely to be the arm in front of the starfish. When trying to locate an odor, the ray sensing the odor most intensely seems to be the one which takes charge, directing movement in its own direction. 1 They have no capability to plan anything. It’s all reflex. What is the starfish reproduction process? They gather in groups. Females release their eggs( gametes) and males release their sperm into the water and by chance they meet up and then the starfish lifecycle begins.

Some starfish reproduce by losing part of an arm which will then grow into a new starfish. What is the life cycle of a starfish? They start life as embryos then become bipinnaria, then brachiolaria. They are still relying mainly on their egg yolk sac for survival and are floating with the surface plankton. When of sufficient size, they drop to the seafloor and continue growing into adulthood. How long do starfish live for? Their lifespan ranges from 5-35 years What is the scientific name for starfish? Asteroidea Where can you buy a starfish? Most salt water fish stores carry them. Some Petco’s do as well. Chocolate chip starfish are commonly kept as pets. Here’s one being fed shrimp: Are they difficult to keep as pets? No. Here’s a Petco’s care sheet . Do starfish have a heart or circulatory system? Starfish do not have a true circulatory system. An extension of the stomach known as “pyloric cecum” extends throughout each of the arms of the starfish and supplies nutrients to all parts of the body.

Thus, starfish do not need a true circulatory system.Starfish also have no true heart or anything that more than merely resembles a circulatory system. Starfish have a well structured system of tubes that works in lieu for the circulatory system. 2 Are starfish edible? Yes. In Japan they are considered a delicacy. Starfish on a Stick Are starfish asexual? They are asexual in the sense that they can reproduce by regeneration from a fragment of an arm but they don’t typically reproduce asexually instead relying on the traditional egg/fertilization method. Are their male/female starfish? Yes, but you have to dissect them to tell whether they are male or female. Are there any endangered starfish? No. None on the IUCN Red List Do starfish have a mouth? Do starfish have teeth? Starfish Information You Are At: AllSands Home > Science &GT; Animals > Starfish information Starfish Information The starfish is an amazing animal, surviving without the benefit of eyes, ears or a nose. Despite all this, they continue to thrive.

If you've ever had the privilege of walking the beach, you've probably already noted that the starfish is one of the most popular creatures of the sea world. Perhaps one of the most unusual animals, as well, the starfish is still somewhat of a mystery. DESCRIPTION The starfish (which is also known as a Sea Star) includes in its class, any marine invertebrate of the class Asteroidea. There are approximately 1800 different species of the common starfish, none of which can be classified as fish, despite their name. APPEARANCE This star-shaped carnivorous animal is usually a dull yellow or orange, but can also be brightly colored. As a natural defense mechanism, the starfish is able to change its body color to hide or escape from predators. Starfish vary greatly in size from under 1/2 inch to over 3 feet. The arms of the starfish are used for movement, catching prey and digestion. Unlike other animals, the starfish is able to grow a new arm if one is lost. Many starfish have five arms, but there are some deep-water species that carry more than fifty.

The starfish's arms surround a small disc-like body, which houses a mouth in the center of the underside of the body. CHARACTERISTICS Starfish bodies are highly flexible. The starfish is capable of making itself surprisingly rigid through the use of skeletal plates that are imbedded in their flesh. Blunt spines project from these plates. By making itself rigid, the starfish is able to protect himself from being eaten, handled or moved by protracting these spines. In addition, some starfish are covered with an organ called, pedicellariae. Pedicellariae make the starfish's arms light sensitive, so they are better able to manipulate themselves. Despite the added benefits of their many arms, the starfish has no eyes, ears or nose and rely solely on their legs for almost everything. The upper body of the starfish houses tiny holes that admit water into the animal's vascular system. This system includes several canals that extend to the starfish's arms and connect to many sucker-tipped, tubed feet. The hydraulic pressure of the circulating water helps to extend the tube feet and allow the starfish to move in a multitude of directions on the ocean floor.

Because of their many arms, starfish are able to wedge themselves in small nooks and under rocks as a means of protection. Most starfish feed on slow-moving or stationary animals. Clams, oysters and snails are the diet of choice, though starfish are also known to eat fish eggs and mollusk. The starfish stomach actually extends itself through the mouth to grab and consume food. The material is then transported to the starfish's digestive glands, which are located within its arms. REPRODUCTION Most starfish spread their eggs and sperm naturally into the water, and fertilization occurs externally. A female starfish will shed several million eggs into the water in a two-hour period. After it is matched with sperm, a hollow ball (called the blastula) develops. Much like the butterfly, the starfish changes form during early life, transforming itself from an embryo to blastula to larva to miniature starfish, a process that takes two months. LIFE Juveniles are any starfish under the age of six months. These young starfish begin life with three or four arms and only begin to develop more as they provide themselves nutrients by consuming encrusting algae.

Their rudimentary, poorly developed arms are not well used at this age, and because of their slow nature, many juvenile starfish do not survive. By the age of six months, starfish are considered mature. Their diet begins to change from algae and eggs to coral and then to more adult like foods. The starfish becomes sexually mature at the age of two years. After their third or fourth year of life, it's thought that starfish go through a senile phase where growth declines dramatically and reproduction is low. It is not known exactly how long the common starfish lives. Scientists have successfully kept starfish alive up to eight years, but their exact lifespan is not known. TODAY Today, starfish live close to the sea around the world and typically stay in groups of forty or more. Most starfish live in the deepest parts of the sea and are often found hiding under rocks or in tide pools. Starfish are sometimes carried into shore during high tide. These are the starfish you may commonly see on the sand or close to shore. Because starfish can only survive two hours out of water, it's recommended that you leave starfish where you find them. Sea Star Eyes - How Do Starfish See?

By Jennifer Kennedy Updated January 13, 2017. Starfish , which are more scientifically known as sea stars , don't have any visible body parts that look like eyes. That leads to the question of what they might use to see. What do starfish use for eyes? While it may not look like starfish have eyes, they do - although they're not like our eyes. A starfish has eye spots that cannot see much in the way of details, but can detect light and dark. These eye spots are at the tip of each of the starfish's arms. That means that a 5-armed starfish has five eye spots, and a 40-armed starfish has 40! How to See a Starfish's Eye A starfish's eye spots lie underneath its skin, but you can see them. If you get a chance to gently hold a starfish, often it will tilt the end of its arms upward. Look at the very tip, and you might see a black, or red dot. That's the eye spot. Cartoons that portray starfish with a face with eyes in the center of their body are therefore inaccurate.

A starfish is actually looking at you with its arms, not from the center of its body. continue reading below our video 10 Facts About the Titanic That You Don't Know It's just easier for cartoonists to portray them that way. Structure of the Sea Star Eye The eye of a sea star is very small. On blue star, they are only about half a millimeter wide. They have a groove on the underside of each arm that has the tube feet that stars use to move. The eye is made of a couple hundred light-collecting units and is located at the end of one of the tube feet on each arm. It is a compound eye like that of an insect, but it doesn't have a lens to focus the light. This reduces its ability to see anything but light, dark, and large structures such as the coral reef it needs to live on. What Can Sea Stars See? Sea stars can't detect color, they don't have the color-detecting cones that human eyes do, so they are colorblind and see only light and dark. They also can't see fast-moving objects as their eyes work slowly. If something swims by them fast, they simply won't detect it.

They can't see any details because they have so few light-detecting cells. Experiments have shown they can detect large structures, and even that was a surprise for scientists, who for a long time thought they could only see light and dark. Each eye of the sea star has a large field of vision. If all of their eyes weren't blocked, they could see for 360 degrees around themselves. They could probably limit their field of vision using their other tube feet on each arm as blinders. Sea stars likely see just enough to be able to get to where they want to be, on a rock or coral reef where they can feed. Ladywildlife's European Star Fish Page European Starfish To see pictures of animals click the blue dot.. The European starfish is a brownish orange color and has five tapering limbs that give it its star shape. It is a common seashore sight along the coastline of western Europe. The European starfish, which is all legs and has no real head, seems a strange creature. It uses its suction feet to crawl along the seabed and to grasp its prey. With these suction feet, it can even pry open mussel and clam shells.

Characteristics: The bodies of starfish are very different from those of most other animals. The European starfish has five identical arms radiating from a flat central area, and other starfish have as many as 50 arms. The central area contains the mouth (on the bottom), the anus (on top), and the main stomach organs in between. Bony plates in the starfishï¿½s body give it support. All over the surface there are tiny pincers that snap shut to defend against creatures that try to settle on the starfish. Sensitive tube feet with suction pads line the bottom of each arm. These podia detect and trap prey. To move forward, the starfish repeatedly extends its tube feet and fixes each to a new spot. Food and Feeding: Some starfish filter nutritious particles from the water, but most, including the European starfish, are predators. They eat sponges, corals, worms, mollusks, crustaceans, other starfish, and small fish. They use their tube feet to detect prey from chemical signals in the water and to ensnare their victims.

The European starfish is especially fond of bivalve mollusks such as mussels, oysters, and clams. These creatures seal their shells tight when attacked, but the starfish wraps its body around the prey and uses its tube feet to pull the two halves of the shell slightly open. It extends its stomach outward through its mouth and into the shell itself. The starfish releases digestive juices that break down the victimï¿½s tissue. The resulting soupy mixture is absorbed into the extended stomach. A starfish usually moves only when feeding or if the seabed temperature changes. Breeding: The male and female European starfish look similar. During the spring spawning season, they produce millions of sex cells and release them into the water through special pores. When a female releases sex cells, she triggers neighboring males and females to release theirs, and many of the cells intermingle. A fertilized egg hatches into a floating, bean shaped, symmetrical larva. It grows twelve arms and floats near the surface for several more weeks. Eventually its arms are replaced by three new arms. The larva inverts itself and, using its three arms and a suction foot, anchors itself to the seabed.

A star shaped bud grows on the rear of the larva and eventually takes over. After a year it is a mature, but small, adult, measuring four inches across. Naturewatch: European starfish are often found on mussel beds. Other European species include the cushion star, with stubby arms, and the sunstar, with 10 or more arms. The dry remains on beaches are the animalï¿½s bony plates. The softer parts have usually decomposed or been eaten. Key Facts:

Question: How many legs (or arms) are most usually on a starfish?
Answer: Five