1. Octopus, also known as octopus, its English name is octopus, is a mollusk that evolved from cephalopod molluscs. The body is generally small and the eight tentacles are thin and long, so it is also called "octopus".

2. The octopus is a sensitive animal. Its nervous system is the most complex and advanced among invertebrates, including the central nervous system and peripheral nerves, and is located on the brain ganglia. It also divides into auditory, olfactory and visual nerves.

3. The most developed of its sensory organs are its eyes, which are not only very large, but also wide open and motionless, like an owl. The structure of the eye is very complex, with a cornea in front, a sclera surrounding it, and a well-developed lens comparable to that of vertebrates. In addition, there is a small pit in the skin behind the eye. This unusual small pit is specially used for the sense of smell.

The expansion is as follows:

1. Although small octopuses are ugly in appearance and high in skill, they are by no means cruel. They are extremely gentle, friendly and timid animals. Among the more than 200 known species of octopus, most individuals are very small. Only large species live in the North Pacific. Their tentacles are about 5 to 10 meters long and their weight can reach 45 kilograms. As for whether there is a larger giant chapter in the deep sea, it remains to be confirmed by investigation. Encountering a giant octopus must be extremely scary in imagination, but people rarely see octopuses when diving underwater. They don't like the flat seabed and always hide in cavities in rocks.

2. If you really encounter an octopus underwater, don’t be too panicked. They always take the initiative to retreat. A well-known French expert, Coust, once made a special observation on octopuses. He dived underwater, found the octopus's cave and approached it. The octopus looked very nervous, and its body immediately swelled up. It stared closely at the visitor and extended its tentacles. He stretched out the cave and used all the objects he could grab to raise his cover, as if he wanted to seal his hiding cave tightly. His body color would also change due to fright. Once it finds that a visitor refuses to leave, it will escape from its hiding place, flatten its body toward you, and then suddenly escape quickly.

3. Divers often encounter octopus underwater. According to their experience, only when the octopus is frightened will it grab the objects around it. If someone is next to it at this time, it will It can catch people, but its purpose of catching things is only as a support. Don’t panic if you are caught. Just gently catch the octopus and float to the surface with it. It will never resist at this time. After reaching the water, just pat it or stroke (but don't tickle) its body gently, and it will release its tentacles and leave you.

4. Many divers have confirmed that octopuses will never actively attack people. When they are forced to do so, they would rather use other escape methods than take offensive actions. For example, it will change color to show alarm or emit "smoke". In short, it will try its best to get away from you, just to hide in the bunker as soon as possible. Facts have shown that the octopus is a timid and gentle animal. However, since the octopus's tentacles are very powerful and its suckers are difficult to get rid of, when you encounter a large octopus underwater, it is best to stay away from it to avoid misunderstandings and entangling you. On the body.

5. The female octopus is perhaps the most dedicated and self-sacrificing mother in the world. It only gives birth once in its life, laying hundreds to thousands of eggs (smaller ones for larger ones, more for smaller ones), which they hide in their own caves. During the incubation period (different varieties require different times, usually 4- 6 weeks), the female octopus guards the cave every step of the way, without eating or sleeping. Not only does she have to drive away predators, but she also keeps swinging her tentacles to keep the water in the cave constantly renewed, so that the unhatched babies can Get enough oxygen.

The day the baby octopus emerges from its shell, the female octopus has completed her lifelong duty and died of exhaustion. How many animals in the world can have such great motherhood!