We Urchin You To Meet Us
Hehe! Ok, we do love a good pun. Today we strapped on our dive gear (Ellie has a hard time getting her trunk covered) and we headed to ocean floor to see where the purple sea urchins call home. These kelp forest inhabitants are essential to the kelp forest ecosystem. Let’s learn more about them!
- Purple sea urchins have spines that cover their bodies. These spines can move on ball and socket joints (like your shoulder).
- The urchins use their spines to catch food and to protect themselves.
- Sea urchins, like their relative the sea star has tiny tube feet that move them along the ocean floor.
- Purple sea urchins have toothlike plates around their mouths called the “Aristotle’s lantern. These strong plates help them dig holes in stones. They dig these as their burrow hideaway.
- Purple sea urchins live in hordes. A group can decimate an entire kelp forest, by eating the plants from the bottoms up.
- Purple sea urchins are a favorite food of the sea otter and the sunflower sea star- which swallow the urchin whole! WOW!!
- Young sea urchins have green spines!
- Like other echinoderms (the family sea stars belong in), they have five fold symmetry.
We had such fun diving and watching these animals. Sea urchins don’t have eyes, they have light sensitive cells on the tips and the base of their spines. Soooooo cool!