Sea Urchin

Sea Urchin found Worldwide

The sea urchins make up a large majority of the Echinoidea class and may be found worldwide in oceans. The size of sea urchins ranges from 3 centimeters to 10 centimeters in diameter. They are found in many different colors including the darker shades of red and purple as well as brown, green, olive, and even black.

Sea Urchin Speed

Sea urchins are not fast creatures. In fact, they move quite slowly. They eat mostly algae, yet are considered a delicacy around the world. Other food includes sponges, crinoids, mussels, brittle stars, and the like. Predators of the sea urchin include wolf eels, otters, and others. Having predators of the sea urchin is really important because without them the sea urchins will create an urchin barren. This means they will completely deplete the fauna and microalgae in their environment.

Sea Urchin Family

 

The phylum Echinodermata includes sea urchins as well as crinoids, starfish, brittle stars, sea cucumbers, and other. Sea urchins have tube feet, hundreds of them that are adhesive and help them move about. Sea urchins have pentamerism, which is the fivefold symmetry that makes up echinoderms. This is not readily obvious; however it is easy to see by looking at a sea urchin’s shell once it is dried out.  

 

Sea Urchin and Cucumbers

The subphylum Echinozao is made up of the sea urchin and sea cucumbers. The defining nature of this subphylum is to be globoid in shape and not have any rays or arms. Some people confuse the tube feet around a sea cucumber’s oral opening as tentacles or arms, but they are actually their tube feet that have been modified to a degree. They are not like the starfish or brittle stars with actual arms.

 

Sea Urchin Groups

 

The sea urchin is not just one group, but several. It includes the Cidaroida, Echinoida, as well as others. Other sea creatures that are part of the Echinoidea group include heart urchins, sand dollars, and sea biscuits.

There are many photos of sea urchins that help scientists study them and learn more about them. Additionally, individuals can easily observe and even touch sea urchins in aquuarimus worldwide.