Short-spined urchins are large, well-rounded sea urchins, completely covered in short, white spines. Long tube-feet extend well beyond their spines.
They inhabit beds of seaweed, where they use their tiny tube-feet to camouflage themselves by holding straps of seaweed, rocks or other debris over their bodies (as pictured). This behaviour gives them their international name of “collector urchin”.
Short-spined urchins are opportunistic feeders, and feed voraciously on algae, seagrass and bacterial mats. Their behaviour is unaffected by the day-night cycle, and this is unusual amongst urchin species. This unusual behaviour has made short-spined urchins useful for rehabilitating coral reefs which have been infested by alien seaweed species.
These urchins are nutritious and edible – regularly preyed upon by humans, octopuses and puffer fish.