The spinelets on this urchin can sting.
This month I am featuring two urchins. I am always surprised when I come upon a reef that is covered in urchins. They are such peculiar creatures that spend most of their life in the exact same spot every day just eating the algae that is close enough for them to reach. I find them to be equally beautiful and objectionable. They are beautiful for their complexity and delicate spines, and objectionable because of how painful I know that they can be to the touch. The spinelets on this urchin can sting.
The banded sea urchin, or the double spined urchin is in the sea urchin family Diadematidae. Its scientific name is Echinothrix calamaris. The shell is slightly oval, and its spines grow to be 10 to 15 cm in length. The radios are hollow and are often times striped from yellow to dark brown. The banded sea urchin has a visual receptor that gives it a basic vision. They can be found living at the surface all the way down to 230 feet. They are active at night, using their tubed feet to move about.
Fun Facts
- Triggerfish and wrasses will nibble away their spines and then eat their fleshy undersides.
- They can shoot their radiolas filled with venom a short distance.
- Certain species of shrimp and fish live symbiotically within the spines of the banded sea urchin.
- The banded sea urchin feeds primarily on algae.
The banded sea urchin can shoot their radiolas.
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