Most rays have a hard spine on top of the tail. The spines have serrated edges with sharp points that point back toward the base. Spines can be lost and replaced, and sometimes rays have multiple spines. The spine is used only for defense. A sting mig ht occur, for example, if someone accidentally steps on hidden ray and the animal tries to protect itself.
Most rays are bottom-dwellers.
As a ray rests on the bottom, its mouth and gill slits face the bottom. Visitors often ask how to tell a male ray from a female.