Do dragons exist today? Although often mistaken for a mythical（神话的）creature, we actually live among several different types of "dragons. " For example, you may have seen dragonfly flying over a summer garden or read about a Komodo dragon lizard. The ocean has its share of dragons, too.
The blue dragon is a marine（海洋的）snail without a shell. It is commonly known as a blue sea slug（海参）. This particular species of marine snail can swallow a bubble of air（which it holds in its stomach）that enables it to float upside down on the surface of the ocean. The underside of the slug is blue, and it back is a gray color. This helps to conceal it from birds flying overhead and from fish swimming below.
Blue dragons feed on poisonous jellyfish and other similar species. When food is in short supply, they will eat each other. They collect toxins（毒素）from the jellyfish and store it in many finger-like structures. This ability to store poison gives them a much stronger sting（刺）than the jellyfish itself. They use this poison as a defense against enemies. The sting can also be felt by people.
These creatures are rarely visible for study and observation except for when they come close to land during times of onshore winds. They have been seen in Hawaii and in tropical（热带）waters around the world. Beware（当心）of the blue dragon's sting!
