Despite its brain has the size of a walnut, the Octopus is one of the smartest invertebrates in the world; some of them use tools, such as shells, to dig, and to hide from predators. It is able to change colour to blend in with its surroundings, and is able to jump upon any unwary prey that strays across its path.

There is a species known as the Mimic Octopus, or camouflage octopus, which can imitate the shape of other marine animals.
This mollusk has eight “arms”, each of them is equipped with suction cups 240 arranged in two parallel rows, exerting a force of traction up to 15 times its own weight. It has three hearts, two are used to pump the blood through the gills; the third heart  pumps the blood through the entire body.
The octopus has complex eyes; like human eyes they have horizontal pupils that always remain in the same position. Hidden inside the head, it has a keratinized beak with which can break the shells of other mollusks.
The friendly cephalopod are solitary and unprotected, which would make them vulnerable. If an octopus is detected or annoyed,  it will escape distracting the predator with a cloud of black ink that confuses  both the sense of smell and sight of the enemy. Regardless of gender, the majority of octopus lives up to 5 years, which limits their ability to gather and learn information.
In order to attract females, octopuses perform a courtship ritual. They use using a tentacle called ectocotile to transfer the sperm to fertilize a special cavity of the female during the copulation. The female lays eggs (in numbers ranging from 50,000 to 400,000), and defend them from possible predators until they hatch. In this period that ranges between 1-2 months it does not eat and lose much of its weight. It dies after hatching.