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Fragile pink sea urchin

Fragile pink anemone

On Exhibit: Giant Pacific Octopus

Animal Facts

  • Scientific Name

    Strongylocentrotus fragilis

  • Animal Type


  • Diet

    plant and animal scraps, including kelp that drifts down from surface waters

  • Size

    to 4 inches across (10 cm)

  • Relatives

    other sea urchins; sea stars; sand dollars

  • Habitat

    Deep Sea

  • Range

    seafloor, 300-1,600 feet (91-488 m)

Natural History

An urchin "walks" on tiny tube feet, much like a sea star does. When an urchin finds a scrap of kelp—its favorite food—it uses its five rasping teeth to scrape away at the kelp and push tiny pieces into its mouth. This urchin feeds on plant and animal scraps that drift down from shallower waters. The fragile pink urchin is an abundant sea urchin off our coast. It may go for long periods without food, surviving on stores of fat.


Anything that finds its way into the ocean, whether it's tossed away as trash, washes off a beach or falls off a boat, may eventually make its way to the deep sea. It's important to realize that the deep sea is not so far away that it's beyond the reach of human activities. Living creatures in the deep are affected by what we do at the surface.

Cool Facts

An urchin's mouth is on the bottom of its body.

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