Octopus has the following characteristics:

1. Octopus is a mollusk and has no bones.

2. Octopus is a cephalopod, with short oval shape, saccular shape and no fins. The boundary between the head and the body is not obvious * * * There are 8 brachiopods, which grow on the head and maintain an extraordinary balance.

3. Octopus skin contains highly developed cells containing pigments, which can change the body color very quickly. The body color of octopus can be used as a protective color, and it is said that it can also reflect the mood of octopus.

4. Octopus is a carnivorous creature. It is a terrestrial mollusk that feeds on claptra and crustaceans (shrimp, crab, etc.), and some species feed on plankton.

5. Octopus has 24 suckers on its wrist, and each wrist has two rows of fleshy suckers. These suckers can swim freely underwater to catch prey. I usually crawl with my wrist, sometimes I swim by stretching the carpal membrane, so I can hold other things strongly and use the funnel at the bottom of my head to spray water for quick retreat.

6. Octopus breathes by sucking water into the mantle and expelling it from the body through a short funnel-shaped body tube. When the octopus is frightened, it will spray water from the body tube and move quickly in the opposite direction by hydraulic jet to avoid danger.

7. The most well-known octopus is the common octopus, with a medium size, which is widely distributed in tropical and temperate waters all over the world and lives in caves or crevices on the rocky seabed. This species is considered to be the most intelligent among invertebrates.