Stingrays are sea creatures that are closely related to sharks. If you're snorkeling in the Cayman Islands and see a large, flattened fish with a long tail and eyes on top of its body, you're looking at a stingray.
Like their shark cousins, stingrays have cartilage instead of bones; stingrays look completely different from sharks, though. Stingrays' bodies are shaped like a rounded diamond, and their gills are on their underside. Their venomous tails are dangerous, giving them the sting part of their name—but most stingrays are shy and docile, and safe to swim near as long as you don't step on them.