The octopus belongs to a subclass of cephalopods. They are symmetric, with two eyes and four pairs of their arms (the reason they have gotten the title octopus, which means eight). Despite the fact that the octopus is a cephalopod, it is very different from its relatives such as oysters and snails. It is more closely associated with the squid.
The octopus does not have a shell; it’s a hard beak, with its mouth in the centre. As they don’t have a skeleton they could squeeze through narrow places and their favorite location is coral reefs.
If you meet an octopus under the water, then move away as fast as possible. They may not seem dangerous, but there is one type of octopus, the blue ringed octopus, which is deadly. The octopus can change its colour from red to gray, yellow, dark or greenish. At their back they have a type of muscular siphon. Water comes in the siphon, and the octopus takes the oxygen from it. This sucking siphon helps it to move fast through the water. In this manner, the octopus can run away from a predator that has come too near.
The octopus moves by swimming and crawling. When they want to travel slowly, they tend to crawl with some swimming. When they’re aided by the jet propulsion, they move really fast, but even then they use swimming and walking.
When they crawl, they actually walk their arms. Usually they use many legs simultaneously, on soft and solid surfaces. Recent research from 2005 showed that some octopus can walk on two arms.
This way of moving (locomotion) helps octopus to flee from a possible predator. However, moving assists the octopus to catch its prey also. The octopus eats mainly fish and goats, but when it’s hungry it catches everything.
For ingestion, the octopus uses its strong jaws, which look like the beak of a parrot. It can bite strongly and at precisely the exact same time that it injects its poison. The poisonous liquid helps it in disabling its prey and its long arms, even though they make the octopus look unusual with its sucking holes, it’s with these it catches its prey and squeezes it firmly.