Jellyfish are fascinating creatures. They are umbrella or bell-shaped shaped and made up of at least 95% water and they have no brain, no backbone (creatures with no backbone are called Invertebrates) and they have no blood. To move they take in water and squirt it out behind them which pushes them forwards or they just float along with the water currents. They have tentacles with stinging cells and this is what they use to catch their food which is usually plankton, fish eggs and smaller fish or sting us if we get too close or accidentally tread on one. What they eat depends on how big they are themselves really. Jellyfish have inhabited the oceans for over 500 million years, long before dinosaurs and sharks. In some countries such as Japan Jellyfish will be caught and dried to eat as a special treat!