Sea Urchin

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Sea Urchin Tube Feet - Up Close

The tube feet that are not busy pulling the urchin along appear to be engaged in a slow dance. The feet below look a little blurry, because they were moving when the picture was taken. Notice how long and thin they are. Tube feet not only help the urchin move, they also are used to grasp food, and they are part of the respiratory or breathing system.

Sea urchin tube feet

Sea urchin extending beyond the spines. Image by Jerry Kirkhart via Wikimedia Commons.

Watch Sea Urchin Tube Feet in Action

The tube feet are part of the urchins water vascular system. They work like a hydraulic system. The urchin contracts its muscles to push water into the tube feet. This extends the feet outwards. When the muscles relax, the feet retract.

 

Read more about: Sea Urchins Do Research

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Urchin tube feet
This is a scanning electron micrograph, or what is usually called an SEM image, of a sea urchin tube foot. You will notice the suction-cup end. Because the tube foot is retracted (pulled back), there are a large number of folds in the long part of the foot.

Sea Urchins Do Research

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