Why do starfish have suction caps?

Starfish don't have suction cups. They have tube feet that act like suction cups.

Here's how it works:

* Tube feet are small, flexible, and hollow projections on the underside of a starfish's arms.

* Each tube foot has a terminal disc, which is like a tiny suction cup.

* Water pressure is what allows the tube feet to work. The starfish uses its vascular system to pump water into and out of the tube feet.

* When water is pumped into a tube foot, it extends and the terminal disc presses against a surface.

* When water is withdrawn, the tube foot retracts and releases the hold.

These tube feet are incredibly useful for starfish:

* Movement: They allow starfish to crawl across surfaces, including smooth ones like glass.

* Feeding: They help starfish grip onto prey, such as clams and mussels.

* Attachment: They enable starfish to stay firmly attached to rocks and other surfaces, even in strong currents.

So, while starfish don't technically have suction cups, their tube feet act very much like them, giving them amazing abilities to move, feed, and survive in their environment.