urchins

green sea urchin

Scientific name: Strongylocentrotus droebachiensis

Family: Stronlocentrotidae 

Phylum: Echinodermata

Typical size: 5 centimeter diameter

Depth range: 0 to  1,100 meters 

Description: Urchins have 3 main structures in their body: spines, tube feet, and pedicellaria. The spines provide some protection (but are not venomous for this urchin). The tube feet are used for moving and collecting food. Pedicellaria are thin and flexible stalks that have a small claw like structure that helps it scratch food. 

Habitat and behavior: Lives in the northern hemisphere, and in some arctic waters. They are herbivores that eat kelp and other algae. Some of the green sea urchin’s predators are sea stars, crabs, wolf eels, large fish and seagulls.