Shore Buddies Wisdom Wednesday 09/23/2020
Photo by Manuela Kirschner
Sea Stars have remarkable regenerative powers, when attacked and damaged by predators they are able to grow new arms. They usually have five arms but have been found with 4 or 6 arms, this may be because more than one arm has been damaged at one time! The eyes see only light and darkness. The mouth is found in the centre of the body on the underside. They possess a cleverly evolved arsenal of hydraulic tube feet connected to an elaborate water-vascular system that encircles the animal's mouth and extends via five radial canals down the centre of each arm. Sea stars move very slowly using their water filled tubes and tube feet that stick out through the skin to hold onto surfaces. Their mouth is underneath, but their prey is absorbed outside their mouths when the sea star sits on its prey and forces out their digestive organs from their stomach. Sometimes small parasitic limpets can be found on the underside of arms which can deform the arms. The Blue Sea Star frequently plays host to a tiny shrimp and sometimes a small gastropod snail that are identical in colour to the sea star. The shrimp or snail live in the grooves on the underside of the arms. The above picture shows a blue Sea Star with four tiny snails with blue fan-shaped shells. They stick to the underside and parasitize the Blue Sea Star.