Why are some starfish slimy?

Sea stars, commonly known as starfish, have a unique water vascular system that helps them move and feed. This system is composed of numerous small tube feet, each of which ends in a suction cup. The tube feet are connected to a central water ring canal, which is in turn connected to the madreporite, a sieve-like structure located on the sea star's upper surface.

When the sea star moves, it draws water into the madreporite and then pumps it through the water ring canal and into the tube feet. The tube feet then extend and attach themselves to the substrate, allowing the sea star to pull itself forward. The suction cups on the tube feet help to create a strong grip, and the slimy mucus that covers the sea star's body helps to reduce friction and allows the sea star to move more easily.

In addition to helping the sea star move, the slimy mucus also plays a role in feeding. Sea stars are predators, and they use their tube feet to capture and eat a variety of prey, including mollusks, crustaceans, and echinoderms. The slimy mucus helps the sea star to grip its prey and prevents it from slipping away.

The slimy mucus also helps to protect the sea star from predators. The mucus contains a number of chemicals that can deter predators, and the slimy texture of the mucus can make it difficult for predators to grip the sea star.

Overall, the slimy mucus that covers the sea star's body plays an important role in the sea star's ability to move, feed, and protect itself.