Sea stars and sea urchins

Sea stars, sea urchins and other echinoderms

Step into the underwater world of wonderful shapes and colours and see some of the spiniest animals beneath the waves.

Echinoderms (Ancient Greek: ekhinos = spiny, derma = skin) include sea stars, sea urchins, feather stars, brittle stars and sea cucumbers. All are found in marine environments in a range of habitats from intertidal surf beaches to the deepest oceans. Although diverse in size and unusual shapes, all echinoderms have an internal calcareous skeleton and a water vascular system that operates their tube feet.

Marvel at how some echinoderms have excellent powers of regeneration. Sea stars often regrow arms bitten off by predators and, if disturbed, brittle stars drop off an arm or part of an arm. This allows them to escape predators as the cast-off arm continues to wriggle to distract the attention of the attacker.

Find out more about the remarkable echinoderms in the Australian Museum collection factsheets.