How do starfish move?
The sea star, or starfish has hundreds of tube-shaped feet on its underside. Each foot has a muscle that pushes water from inside the starfish down into the tube to make the foot move forward. When this muscle relaxes, the foot stops moving and the next foot in line takes a step. So by moving the feet in order, the starfish walks. Some sea stars can climb smooth rocks and aquarium walls by using those muscles to pull water out of the tube feet after it takes a step, so the flat bottom of the foot bulges inwards and forms a suction cup. When the muscle relaxes, the suction cup lets go and it takes another step forward and attaches the foot to the wall again.
