The common octopus is a species in the class of the cephalopods and therefore belongs to the phylum of the molluscs.
Description
Octopus vulgaris has a round head with eight arms on one end. Two rows of suction cups are located on the inside of these arms. Its eyes stand out clearly and are directed to the right and left instead of looking in front. The colouring of the Common Octopus is variable, since it can change it quickly threw specialized muscles. This allows it to adapt itself perfectly to its background and become invisible to hunters and prey.
Compared to other cephalopods, Octopus vulgaris has no remaining of a shell. This makes it incredibly flexible and allows it to even slip through very small holes.
The Common Octopus can reach a length of more than one metre.
Habitat and Distribution
One finds the Common Octopus mostly on the ground of rocky reefs down to depths of 200m. At night I observed very young individuals on sandy areas. When diving in the Canaries you can see Octopus vulgaris very often. In addition, it spreads in the eastern Atlantic from Great Britain, along the coast of Europe and Africa, to at least Senegal. This also includes the Azores, Madeira, Cape Verde and the Mediterranean Sea.
Biology
Octopus vulgaris lives solitaire. It is actually a nocturnal hunter. In contrast to its closest relative, the white-spotted octopus, one can see it also during the day. Most of the time, however, it is just hiding in a hole or squeezed into a crevice.
The diet of the Common Octopus consists of crustaceans, mussels, slugs, and fish. These do not have to be small. During a night dive, I could observe how an octopus fed on an about 50cm long Atlantic Trumpetfish.
If Octopus vulgaris feels threatened, it can eject an ink cloud to confuse its attackers. In addition, it is able to adjust its colour to the background and thus becomes almost invisible.
Reproduction
To gain attention of females, the males flaunt. During the act of reproduction, the male clamps the female and injects its sperm. After the Common Octopus did reproduce, the male usually dies very quickly. The female yields 120000 to 400000 eggs in long white strings. It hides them in a column or hole. The oviposition can extend for up to one month. In the breeding time, the female is guarding her eggs and hardly taking any food. If the larvae hatch after 25-65 days, the female usually dies. Thats why Octopus vulgaris becomes only 2 years old.
The male reaches sexual maturity with about 9,5 cm and the female with about 13,5 cm.