Octopus, like the fish around them, lives in the water, and their names also contain the word "fish", so many people will think that octopus is also a fish. In fact, octopus is not a fish, but a mollusk. The difference between mollusks and fish is relatively large and can not be confused. Generally speaking, the fish has four characteristics is quite prominent: First, the vertebra is the essential spot; Second, fish have fins and use them to swim; Third, fish have upper and lower jaws; Fourth, fish have gills and need them to breathe. However, octopuses do not have these four characteristics, which shows that they are not fish.
a social animal refers to an animal that takes a collective as a unit when carrying out various activities, such as hunting, sleeping, migration and other activities. Octopus itself is a relatively valuable marine life, although they live in the same environment as fish, but they belong to mollusks. In the process of studying their habits and characteristics, researchers have found some octopus nests underwater, in which many octopuses live. Therefore, octopus may also be a social animal. However, it is also common to see a single octopus distributed on the seabed, their IQ is high, they can change color, and their ability to hunt is relatively strong.
