John Michael Bullock-Bahama Sea Star

John Michael Bullock-Bahama Sea Star

Sea stars have no blood. Instead, they regulate their bodies using a water vascular system. This system not only allows for respiration, it also provides the necessary water pressure to operate the star’s hundreds of tube feet. Water moves through the madreporite, the small spot on top of the animal, into a ring canal. From there, the water flows through the radial canals in each arm and finally reaches the tube feet. The water pushes the feet out, reaching for the nearest substrate to attach to. Once a foot touches something, it will shrink back. This helps the suction cup foot to stick. When the star wants to let go, it pushes water back into the foot which will extend and release the suction. The process is fairly slow but extremely powerful. Sea stars can easily pull apart bivalve shells in order to prey on the meat inside.

Information & Research by Kristin Cutshall

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