Also known as Eleven-armed Prickly Sea Star, Eleven-armed Starfish, Many-armed Sea Star, Many-armed Starfish, Prickly Eleven-armed Sea Star, Spiny Star, Spiny Starfish, Starfish.
Found singly, or in constellations, over rocky bottoms, and in tide-pools, of intertidal zones. Colour varies.
They feed on benthic invertebrates and the blue mussel - Mytilus edulis.
Length - 25cm
Depth - 0-50m
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!
Sometimes small parasitic limpets can be found on the underside of arms which can deform the arms.
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.
Their mouth is underneath, but their prey is absorbed outside their mouths by forcing out their digestive organs from their stomach.
Sea Stars are carnivores and feed on almost any food including molluscs, worms, detritus and each other!
Some sea stars like the crown of thorns can be venomous. Ref: https://en.wikipedia.org/wiki/Coscinasterias_calamaria