Jellyfish are invertebrates that live in our oceans. They are of the phylum Cnidaria and the class Scyphozoa.

They have no heart, no brain and no blood. Instead, they have nerve nets, a simple nervous system that allows them to react to external stimuli including light and smell.

They use their stinging tentacles to help them hunt their prey. For human beach-goers, an accidental sting can be painful, and in some cases, deadly.

Want to know more about jellyfish? Visit National Geographic Kids to learn more.