They are invertebrate animals (which have no bones), belonging to the group of cnidarians such as corals and anemones. They are known for their abundant tentacles, which they use to defend themselves and capture prey.

The characteristic swim of jellyfish is due to their ability to tense their bodies to propel themselves through the water, and they also tend to move by taking advantage of ocean currents.

These amazing animals have been around for more than 600 million years, long before the dinosaurs, so they are known as living fossils.