Jellyfish is a low-level marine invertebrate zooplankton, an important plankton in the aquatic environment, and belongs to the phylum Coelenterate taxonomically. We now know about 200 species of jellyfish. Jellyfish are very beautiful aquatic animals. Its body shape is like a transparent umbrella, the diameter of the umbrella body is large or small, and the diameter of the umbrella body of the large jellyfish can reach 2 meters.

Jellyfish have no brains. Its body is only a two-layer structure, and the two layers are adhered by a gel-like mid-layer. With such a simple structure, jellyfish have survived on this ever-changing Earth for more than 600 million years. Before humans ruled land with their brains, jellyfish dominated the unfathomable ocean for a while without a complex brain or neural structure.

The jellyfish looks weak, but has a very strong predatory ability. Zooplankton, small shrimp and fish are all prey for jellyfish. Most jellyfish have long, soft tentacles covered with stinging cells. Besides jellyfish, corals, sea anemones, and polyps also have cnidocytes, and as such, they are all classified as cnidarians.

How long can jellyfish live? There are many varieties of jellyfish, and their lifespans vary. Small jellyfish can live for about a year, while other jellyfish have a lifespan of about a year or two. Jellyfish go through two stages of polyp and jellyfish throughout their life. After the general jellyfish changes from a polyp to a jellyfish body, it can only keep the jellyfish body until it dies.

Looking back at the timeline of jellyfish survival and development, we can go back 650 million years. At that time, the species that thrived on the earth had already experienced 5 scenes of going to the brink of extinction, but the jellyfish still thrived from generation to generation with its tenacious vitality. Just like the species of jellyfish living in the ocean now, there are about 250 categories. Especially small jellyfish can continue to multiply in the face of harsh environments. So until now, the adaptability of jellyfish has been called very powerful.

But it is worth mentioning that many jellyfish contain a lot of toxins, and they are also relatively toxic. And these toxins are to protect themselves in the process of catching prey or escaping, and can give themselves time to escape. Jellyfish have cnidarians on their tentacles. When in danger, the jellyfish will stab the toxin into the body of the prey, and then the prey will be paralyzed for a short time to escape. The strength of jellyfish toxins varies greatly depending on the species. Among the many species of jellyfish, the most poisonous is the box jellyfish. Creatures stung by this jellyfish have little hope of being saved.

The mighty and deadly jellyfish also has natural enemies. Leatherback turtles can move freely among the jellyfish groups, easily tearing off their tentacles with their mouths, so that the jellyfish can only roll up and down, and finally lose their resistance, becoming a delicious meal for sea turtles. Because there is a special substance in the gastric juice of sea turtles that can dissolve the poison of jellyfish, it can eat jellyfish.