What is an Echinoderm?

We've got another marine themed article for you, Defenders - all about a very unique family of animals, the Echinoderms! What is an echinoderm you ask? Well you already know of one very common echinoderm - the starfish...or better yet, the sea star, as they aren't fish at all! Echinoderms also include sea urchins, sea lilies, sand dollars, and sea cucumbers - all ocean animals that are pretty different from the most well known aquatic group, fish. So what do all of these unique sea creatures have in common?

  • Echinoderms are known for their radial symmetry, which means they are symmetrical in a circle, as if they were a piece of pie where each slice would be the same. That's very different from us humans that display bilateral symmetry, where we are only symmetrical when split down the middle.
  • There are roughly 7,000 different species of echinoderms alive today, and they can be found at every depth of the ocean from the shores in the intertidal zone, all the way down into the abyss.
  • There are no land based or freshwater echinoderms - they truly are a marine only group, found only in ocean waters.
  • Most can reproduce asexually, meaning that 1 individual can reproduce by themselves, without a partner.
  • Echinoderms also have strong regeneration properties - when damaged they can regenerate limbs and tissue, even organs...and sometimes, 1 limb of an echinoderm can regenerate the entire body!
  • As many are slow moving or smaller in size, they often have spines or toxins as defense mechanisms to protect from predators.

Echinoderms are a really unique group of animals because they only are found in our oceans, have some really cool properties like how they reproduce and regenerate, and look very different from most other "normal" animals we think of! To learn even more about where echinoderms live and the other creatures they interact with, make sure to check out our Ocean Center, and keep exploring until next time, Defenders!

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