Brown Rock Urchin

Arbacia punctulata

About This Animal

SIZE: 1 - 3 inches

RANGE: Cape Cod to the West Indies

HABITAT: Rocky or shell sea floors; from intertidal to about 750 feet deep

DIET: Algae and sponges

ON EXHIBIT:  Seahorses: Beyond Imagination Exhibit at River Journey

When these urchins are not eating they hide under shells or burrow into the sand or rocks. The name sea urchin comes from the Old English name for spiny hedgehog. An urchin’s mouth is underneath the animal because it is constantly grazing as it moves. The anus is on top of the body between the spines and waste is sometimes excreted as a form of defense. Scientists use larval sea urchins to study embyology and development.