Living Seashore Spotlight: Purple Sea Urchins

Meet one of the newest inhabitants of our Living Seashore exhibit, the sea urchin!

Published March 27, 2015

The purple-spined sea urchin, Arbacia punctulata, can be found in shallow water from Massachusetts to Cuba. It is related to sea stars, sand dollars and sea cucumbers—the star pattern can sometimes be seen from above!

sea urchin

Each moveable spine is attached with a ball and socket joint and is used for protection as well as locomotion. The surface of an urchin's shell has rows of tiny tube feet, which allow the animal to stay grasped onto rocks against the tug of the waves and grab bits of shells or seaweed for camouflage.

The urchin’s spines can sense light! Urchins have generalized light sensitivity all over their bodies.

Along with humans, wolffish and gulls are predators of sea urchins.

Stay tuned for more updates as our newest exhibit comes to life!

Previous Post

Featured Stories

Humpback whale Help Preserve the Endangered Species Act

The Endangered Species Act has supported work that has prevented the extinction of 99 percent of the species it has protected. That work is now under threat.

Read the full story

Atlantic puffin chick born at the National Aquarium Meet Our Trio of Puffin Chicks!

We are excited to welcome three new Atlantic puffin chicks to our Sea Cliffs exhibit!

Read the full story

Related Stories

Living Seashore Wins Top Honors!

Published September 14, 2016

Living Seashore: One Year Later

Published May 12, 2016