Sea Urchin

Common Sea Urchin
http://www.reefed.edu.au/home/explorer/animals/marine_invertebrates/echinoderms/sea_urchins

Sea Urchins are a major group of the echinoderms and the one in which spines are best developed. Sea Urchins have tube feet between their spines and the feet are attached to the animal's water vascular system. The tube feet operate on hydraulic principles and allow the urchin to move about, although rather slowly.


Sea urchins are globe-shaped with no arms. They have a compact skeleton with closely fitted plates, moveable spines with a ball and socket joint. Sea urchins also have powerful scraping jaws known as 'Aristotle's lantern'.
The sea urchin is nocturnal, hiding in crevasses during the day and emerging at night to feed. Sea urchins can be found in both warm and cold water.
Sea urchins are not currently endangered, but like most Reef animals, they are susceptible to changes in water temperature and pollution

White Sea Urchin

Sea Urchin, originally uploaded by Ladymaggic.

Found by Charlie and Jiffy at the rock wall by the first beacon.
This is a beautiful white sea urchin.
You can see his mouth

He was in the water where the Turtle lives.

 Sea Urchins are round in shape. They are covered in  spines. They can grow up to 9 cm wide.

Purple Sea Urchins live on rocky shores of eastern and southern Australia. They can be found in rockpools.
Purple Sea Urchins eat seaweed and algae.
Purple Sea Urchins are grazers. Their mouth is on the underside of their body. They use their powerful jaws and teeth to scrap food off rocks.
Octopuses, crabs and fish eat  Sea Urchins.
Purple Sea Urchins' spines are strong enough for them to dig small holes into rocks. They can chew the surface of the rocks, making a hole in which to hide.