Echinoderms are animals with five-fold symmetry and rows of tiny “tube feet” that they use to move, to hold on to rocks and pilings, and to grasp their prey. Sea stars, sea urchins, sea cucumbers and sand dollars are all echinoderms.
SEA STARS or “starfish” have between 5 and 36 rays (arms) and eyespots that sense light or dark. They can pump water through their bodies to help them move. The underside of each ray has hundreds of tube feet that can catch and pry open prey such as clams and crabs. Did you know that sea stars can grow a new ray if they lose one?
Broad central disc, 20-24 long flexible arms
Flexible, sort skin with sharp prominent spines
Large, often as much as 3 feet in diameter
Can be red, orange, yellow or brownish
Fast moving, aggressive generalist predator
Firm-bodied with uniformly orange to red skin
Always has just 5 long slender arms and no spines
Small, usually no more than five inches in diameter
Blood stars are suspension feeders!
Striped sun star
Firm, leathery sun star with 9-11
long arms, red/orange with bluegray
stripes down each arm
SEA URCHINS are hard, round, cactus-like animals with long spines that protect them from predators such as otters. They move slowly, feeding mostly on algae with the aid of their five tiny jaws. If you look very closely you can see their tube feet waving about, but mind those spines! Sea urchins can have very long lives—some live to be over 100!
Green sea urchin
White to greenish body with tiny tube feet
Short, slender white to greenish spines
Rarely more than 3 inches in diameter
Grazes on kelp and other seaweeds
SEA CUCUMBERS are mainly scavengers that feed on plankton, dead plants and other decomposing sea creatures. Some hide buried in the sand or under rocks, while others crawl around the sea bottom using a water pump and tube feet to help get them move. Can you spot which end of this animal is the mouth? Sea cucumbers go rigid if disturbed and sometimes throw up their insides to distract a predator.