The "Big Red" jellyfish uses its own arms to eat.

Jellyfish are lower coelenterates, taxonomically belonging to the phylum Coelenterata and the class Medusa. The emergence of jellyfish can be traced back to 650 million years ago. There are many types of jellyfish. There are about 250 species in the world, ranging from 10 cm to 100 cm in diameter. They are commonly found in oceans all over the world. The main component of the jellyfish body is water, and it is composed of two germ layers, the inner and outer germ layers. There is a thick mesoglea between the two layers, which is not only transparent, but also has a floating effect. When they move, they use the water jet reflex in their bodies to move forward, just like a round umbrella floating rapidly in the water.

Once a jellyfish encounters prey such as fish, it will never let go easily. Jellyfish look beautiful and docile, but they are actually very ferocious. Under the umbrella, those slender tentacles are its digestive organs and also its weapons. The tentacles are covered with stinging cells, which are like poisonous threads and can shoot venom. After the prey is stung by the stings, it will be quickly paralyzed and die. The tentacles grab these prey tightly, retract them, and use the polyps under the umbrella to suck them. Each polyp can secrete enzymes to quickly break down the protein in the prey. Because jellyfish do not have respiratory organs and circulatory systems, but only primitive digestive organs, the captured food is immediately digested and absorbed in the coelenter. However, if you are stung by a jellyfish, you will generally feel pain and redness and swelling. As long as you apply anti-inflammatory drugs or vinegar, the swelling and pain will subside in a few days. Therefore, when you are stung by a jellyfish and have difficulty breathing, you should immediately implement artificial respiration or inject cardiotonic drugs. Do not be careless to avoid accidents.

The current situation of giant jellyfish

As early as 1993, scientists conducted research on this big red jellyfish. However, there are still many questions that remain unclear, such as what their food is, What animals prey on them and how they reproduce etc. Hudson, a member of the American research team, pointed out that there are many unknown animals in the deep sea that need further study by scientists. The main way to learn about marine animals is through fisheries. As fishing activities increase, ocean fish stocks decrease, and people begin to move deeper into the ocean, so more marine life will be discovered.