Asterias rubens and Asterias forbesi
Sea star are commonly called “ starfish” but biologist call them “sea stars” because these strange animals are not at all like fish. Their relatives are sea lilies, sand dollars, sea urchins, and sea cucumbers.
The red sea star, pictured on this card, is the common sea star of Europe. A very similar one, Asterias forbesi, is found along the Atlantic coast of the United States. Like most sea stars, Asterias lives in tidal zones. It stays on rocks, in the sand, or in tidal pools at low tide. It can even stay out of water for a rather long period of time. The sea star’s body has a rugged look, and its back is dotted with short spines. In a groove on the bottom of each of its 5 arms are dozens of “tube feet” which have suckers on the ends.
These suckers help it move and cling to its surroundings. Asterias have 5 thick arms. The arms often break off at the base if a predator grabs one. The lost arm grows again little by little, so sea stars are often found with 1 arm shorter than the others.
Sea stars digest mussels and oysters in a strange way. They wrap mussels or oyster shell in their arms and then pull open the 2 parts of the shell using their tube feet. They squeeze very tightly until the muscle of the shellfish tires out. The sea star then turns its stomach inside out and puts it into the open shell. The sea star eats its prey while the shellfish is still in the shell.
PHYLUM: Echinoderms
CLASS: Sea Stars
ORDER: Forcipulatids
FAMILY: Asterids
WIDTH: Generally 4 to 6 inches --- often as much as 20 inches
DIET: Mollusks, Such as calms and oysters
METHOD OF REPRODUCTION: Egg Layer
HOME: north Atlantic coast and Mediterranean Sea
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