Life underwater is so diverse and numerous. For Man living on the dry land, animals in the sea with strange forms and colours instill wonder and curiosity. For a long time, all living marine animals were fishes for him. The starfish, although not a fish, is such an animal. Today, scientists are in the process of renaming the animal as the sea star.
The sea star is an echinoderm. Echinoderms are free swimming marine organisms that are found at all depths of the sea. Starfish, sea urchins, and sea daisies are some common echinoderms.
Most starfish have five-arms. But some have as many as 45! There are more than 2000 different species of starfish. Their sizes range from less than 25 millimetres to almost 90 centimetres across. They come in a variety of colours ranging from bright red to yellow and orange. Grey and green are also found.
The most remarkable thing about starfish is their power of regeneration. If you cut a starfish into three pieces, it will grow back as three starfish! Regeneration usually requires that the piece of starfish includes at least one arm and part of the central disc. But in some kinds of starfish, a whole animal can be regenerated from the piece of a single arm.
There is an eye at the end of each arm, usually marked by a red spot. Star fish have feet that look like tubes. These tube feet help them move. A starfish has hundreds of feet. The mouth of a starfish is at the centre of its underside.
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