This black-and-white striped commensal shrimp (Stegopontonia commensalis) spends its entire life on a single long-spined sea urchin. It attaches to the spines head-inward, and scientists aren�t sure what they eat.

This shrimp and urchin were photographed in about 55 feet of water off the south Kohala Coast near Puako Beach on the Big Island of Hawaii.