What food does starfish eat?

Starfish is the most representative class of echinoderms in structure and physiology. it has a flat body, mostly five radiation symmetries, and no obvious demarcation between body disc and wrist. There are 1600 species and 300fossil species, which are widely distributed in sandy seafloor, ooze seafloor, coral reef and oceans of various depths. Let's take a look at what starfish eat.

What food does starfish eat?

Starfish are carnivores and can feed on all kinds of invertebrates, especially shellfish, crustaceans, polychaetes, and even fish. Starfish are greedy predators, because they cannot move as flexibly and rapidly as sharks, so they prey on some slow-moving marine animals, such as shellfish, sea urchins, crabs and sea anemones. the prey often adopts a slow and circuitous strategy, slowly approaching the prey, catching the prey with the tube foot on the wrist and wrapping the whole body around it. Spit the stomach bag out of the mouth and use digestive enzymes to dissolve the prey in its body and be absorbed by it.

Species classification of starfish

1. Banding order: the wrist has two rows of obvious edge plates, no skin Gill, living on the soft seafloor, 2 rows of tube feet, no sucker, arranged in two rows in the walking ditch, which is conducive to living in sediment caves or crawling. Most deep-sea starfish belong to this order, such as maple starfish, which feed on cilia.

2. Spinous order: the marginal plate is very small, and the forked spine is simple or lacking. There are clusters of spines, tube feet have suckers, but forked spines are rare. Camel Haiyan is common on the stony seafloor in Europe. Northern starfish and sun starfish have many short wrists, wide body discs, and ratchet starfish have 15 wrists.

3. Cephaloptera: there are bipetal forked spines with a long handle, and the spines have the function of protection or feeding. Common species of bivalves that feed in shallow water are Red Sea wagons distributed in northern Europe and multi-spine crutches from the Bering Sea to the Korean Peninsula. The 65-centimeter-long starfish on the west coast of North America is one of the largest starfish in the world, feeding on sand, money, sea urchins and so on. Multi-wrist sunflower starfish from Alaska to California have 15-24 wrists. There are up to 50 chrysanthemum starfish in China and the United States.

The predation method of starfish

1. Most starfish have long flexible wrists, suckers on the tube feet, and feed on bivalves. When feeding, the body is on the shell and sucks on both sides of the shell with two wrists. Because of the vacuum effect of the sucker at the end of the tube foot, the pull is strong enough to pull open the shell mouth of the bivalve, the starfish immediately turns out the spray door and inserts into the shell mouth, and secretes digestive enzymes until the adductor muscle and internal organs are partially digested, and the shell opens completely. Then surround the stomach and swallow the food into the mouth.

2. Some species with short wrists and no sucker on the tube foot feed on smaller animals such as small crustaceans. When eating, they swallow the food whole and digest it in the stomach instead of outside the body.

3. The species of deep-sea life are filtered and fed by cilia, and the sediment and organic matter that fall into the body surface are swept into the step ditch to form a food line, and then sent to the entrance, such as maple starfish. Also like the starfish with chicken feet, there are cilia in the gastric caecum, which rely on the movement of cilia to help suction food into the stomach.