Why do jellyfish sting? The jellyfish is one of the strangest forms of life to be found in the sea. First of all, it is not even a fish! It's an animal without a skeleton. Jellyfish are members of a large division of very simple animals called "Coelenterate." Nine-tenths of the body of a jellyfish is composed of a jellylike substance, and most of it is simply a stomach cavity. The jellyfish has no brain and no blood vessels. Some jellyfish are very tiny, but there are others which may have a diameter of 0.5 metres: Jellyfish are a variety of shapes and colors, and there are some which seem to glow when they are disturbed. The most interesting type of jellyfish is called "the medusa:" The name comes from a mythological character called Medusa, who had writhing snakes on her head instead of hair. The medusa jellyfish has tentacles, or feelers, which hang down like snakes from the rim of its umbrella-shaped body. Around the rim are usually a number of tiny eyes, and in the center of the body underneath, is the mouth. It's the tentacles of these jellyfish which often sting people quite painfully. The reason the jellyfish stings is that this is its method of obtaining food. The jellyfish capture other small creatures of the sea by stinging them, and this paralyzes their prey. Then the victim is brought to the mouth by the tentacles. Some jellyfish even have stinging organs in the stomach to complete the destruction of the prey. The tentacles are also used for swimming, though most jellyfish swim simply by contracting and expanding the body. The life history of the jellyfish is interesting, too. The larva, or unhatched jellyfish, swims around by itself for a while. Then it attaches itself to a sea plant or rock and begins growing into a small polyp. Then it branches out like the stalks of a plant, and buds, each bud being a new polyp. The polyps finally take on the shape of a jellyfish, detach themselves, and swim off. Most jellyfish live on or near the surface of the water, but there are a few who live on the bottom of the sea. For Details
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