Regular urchins are spherical animals with a case or shell of close-fitting limy plates. Sea urchins have spines that protect them from predators. However, it is mostly the hard outer shell, from which the spines have usually broken off, that is found washed up on beaches.
"The weather is nice, the sea water is warm, you are going to walk along the seashore, among wave foam which is reaching the beach and refreshing your feet.... Suddenly you sense a puncture under your toe: a sea urchin, hidden under a clump of algae, has defended itself against your foot's aggression! You are angry with the creature, because your toe is painful and also because urchin spines are very difficult to remove. But spines are its unique and passive defence against predators. (Even in its own family: the starfish which is also an ECHINODERM doesn't hesitate to eat its cousins!) (Picture:Strongylocentrotus.)
To console the unfortunate walker, some stages of sea urchin development are very beautiful to observe (and with no danger). At first sight, this echinoderm doesn't have an attractive appearance and it seems not to have interesting microscopic features. It is even repellent: a popular French expression about a man's avariciousness is: 'He has sea urchins inside his pockets'!"
There are nearly 200 different species of recognised sea urchin, that come in all shapes and sizes.
Fun Facts about Sea Urchins:
- Sea urchins are able to clone themselves.
- A sea urchin has no brain. Instead it has a nerve ring, used to power it’s tube feet.
- All sea urchins has five continuously growing teeth; useful feeding tools. They use their teeth for scraping algae, their favorite food, off of rocks.
"The little sea urchin on top is quite unusual. It was discovered by a research vessel near New Caledonia at a depth of 1000 ft." ~ Steve Jurvetson
Visit our Beach Cottage Decorating article about DECORATING WITH SEA URCHINS!