Species index
Species Index
Emerald Diving
Explore the coastal and inland waters of
Washington and BC
Seastar Defenses
Seastars are marine invertebrates belonging to the family "echinodermata", which translates from Greek into "spiny skin".  Most Pacific Northwest seastars carry an arsenal of rough protrusions, spines and tiny pinchers on their exoskeleton to discourage predation and parasites.  The leather star is an exception; it produces a vial mucus through a series of pores on its exoskeleton when threatened to discourage undesirables. 

Macro images of some of these defenses are shown below.  Note the pores on the leather star.  Also note the relatively large clamp-like pinchers on the spiny red star.  If you look closely at the sunflower star image, you can see tiny pinchers dispersed across the animals back.
Leather Star

Leather Star

Morning Sun Star

Morning Sun Star

Mottled Star

Mottled Star

Painted Star

Painted Star

Pink Short Spined Star

Pink Short Spined Star

Red Spiny Star

Red Spiny Star

Rose Star

Rose Star

Sun Star

Sun Star

Sunflower Star

Sunflower Star

Vermilion Star

Vermilion Star

Seastars use thousands of tube-like feet for locomotion.  These feet are tipped with suction cups which the seastar can use to grasp clams, crabs, and other prey and literally pull them apart.  Some seastars use their tubed feet to excavate large holes in sand and mud to expose clams.

Some seastars, such as the sunflower star,  expel their stomach when they devour prey.  Once the prey is consumed, they suck their gut back in and continue their endless  hunt. 

A seastar's mouth is on the underside of the animal and located in the center of the arms. A seastar excretes waste through a vent in the middle of the topside on the animal.

Like urchins, a seastar's anatomy is based upon a five-sided radial symmetry.  However, some Pacific Northwest seastars have more than five arms - and as many as 24!

The sunflower star is the largest and fastest seastar in the world.  This seastar can span 36".  The topside of the sunflower star is actually soft.

Seastars are veracious predators and often hunt each other.  The morning sun star is the top predator amongst Pacific Northwest seastars and will even attack and devour the larger sunflower star.

Seastar anatomy incorporate a water vascular system which controls the water pressure needed  to drive the animals tubed feet.
Cool Seastar Facts