How does starfish take in food

Starfish eat in a very unusual way. They use their feet, which have suction-cups on the bottom, to help them hold on to their prey. How starfish eat clams? The starfish forces open the shell with suction disks on the underside of its body, and then inserts its stomach membranes through its mouth into the opening of the shell.

Star fish feeds on aquatic animals covered by hard shells of calcium carbonate. After opening the shell , the star fish pops out its stomach through its mouth to eat the soft animal inside the shell. After eating the animal , the stomach goes back into the body and the food is slowly digested.

Do starfish bite? They have no teeth and are not dangerous to humans. Not too many people eat them because to some, their taste is not appealing. It has been said that they taste like a Sea Urchin but a bit more bitter and creamier. Some say they taste like ocean water. Because sea stars have no teeth, they cannot chew. They must make their food soupy before they can eat it. Usually they need to be fed every days. How long do sea stars live? On average, they can live 35 years in the wild.

In captivity, most live years when well cared for. Many different animals eat sea stars, including fish, sea turtles, snails, crabs, shrimp, otters, birds and even other sea stars. Predators with smaller mouths can flip the sea star over and eat the softer underside. Starfish feeds on animals covered by hard shells of calcium carbonate. After opening the shell, the starfish pops out its stomach through its mouth to eat the soft animal inside the shell. It can extend its cardiac stomach out of its mouth and over the digestible parts of its prey.

Scientists have discovered a neuropeptide molecule that carries signals between neurons called NGFFYamide, which triggers the stomach to contract and retract back into the starfish. Before extending its stomach out the starfish, it will fast go near to its prey most probably a clam, oyster, etc.

To hold on to its prey it will conveniently creep over the clam, place its whole body over it, and then it will firmly attach its tube feet to the two shell valves of the clam in such a way that the ventral margin of the clam will lie in front of its mouth.

It will then pull apart the two valves held tightly by the powerful adductor muscles and also with the pull action of its tube feet. When the two valves of the clam get opened, the starfish will now instantly extend its cardiac stomach out of its mouth and get it over the digestible parts of its prey that is in the mantle cavity of the calm to quickly devour it.

Sooner or later ingestion of the prey occurs, with the retraction of the cardiac stomach, but before that retraction, partial digestion of the food has to take place. This digestion starts when the cardiac stomach is everted and have got covered over the captured prey here clam for example.

The digestive secretions of the stomach and the pyloric caeca are poured over it, then. Various digestive secretions like the enzymes proteases, amylases, lipases, acts on the food there itself and starts to digest the proteins, starch contents, fats respectively. Digestion thus takes place outside of the body of the starfish and this type of digestion that occurs outside is better to be known as partial digestion.

These partially digested materials are then carried into the alimentary canal by the retraction of the cardiac stomach back inside the oral cavity of the starfish. In the latter course of digestion, some intracellular digestion is also believed to occur within the cells of the stomach and the pyloric caeca.

Next after digestion, the absorption and assimilation of the fully digested food occurs. These are quick processes and nothing so elaborate have been known about these so far. The digested food is absorbed mainly by the pyloric caeca and distributed to various parts of the body as nutrients by the coelomic fluid. Any excess food will be stored in the storage cells of the pyloric caeca as fat molecules for future use of energy.

The intestine of starfish is really very short. In very simple words, once the prey is sipped in through the cardiac stomach, it passes into the pyloric stomach.

From there, the nutrients travel down the pyloric ducts to the pyloric caeca at the end of each arm where nutrients are absorbed and stored. Next, assimilation occurs. Assimilation is the movement of digested food molecules into the cells of the body where they are used. For example: Glucose is used in respiration to provide energy, Amino acids are used to build new proteins, fats used as the future stock of energy.

After the digestion has completed in the stomach and pyloric caeca, and then sooner or later the absorption and assimilation of the nutrients have occurred, then by that time most of the undigested food is sent out through the mouth.

Respiration or gas exchange occurs in two locations on a starfish. The first location is through the thin skin on the ends of the tube feet. Gas exchange also occurs in the dermal gills or papulae. These gills are lined with cilia that move to produce a current. The current brings fresh water so the starfish can absorb oxygen and freshens the surrounding water where the starfish may have just excreted carbon dioxide.

Maureen Malone started writing in She writes articles for business promotion and informational articles on various websites. Malone has a Bachelor of Science in technical management with an emphasis in biology from DeVry University. By using the site, you agree to the uses of cookies and other technology as outlined in our Policy, and to our Terms of Use.

Diet Starfish are carnivores.