The Common Octopus (Octopus vulgaris) is a marine (saltwater) invertebrate (soft-bodied) mollusc in the Octopodidae family. Octopod means eight limbs. It is a cephalopod, related to the squid, cuttlefish, and nautilus.
The Common Octopus has a soft hollow body called a mantle. Its body can change shape and squeeze into small gaps. The mantle has gills (to breath), a brain, and a parrot-beaked mouth. Surrounding the mouth is eight limbs with suckers. It has two large eyes with excellent sight. It has three hearts.
The limbs are often called arms or tentacles, but it it more correct to call them limbs or appendages.
Its mantle grows to 25 centimetres (10 inches) in length. Its arms measure about 100 centimetres (39 inches) long.
It is able to change its colour to camouflage with its environment.
It is found in most tropical oceans around the world, including the Mediterranean Sea. It prefers to live on the sea floor of shallow, rocky, coastal waters. It is benthic because it is a bottom-dweller. It lives in a den, which can be a cave or any hollow space in rocks or objects.
It is nocturnal, active at night. It hunts at dusk for fish, worms, crabs, crayfish, and bivalve shelled molluscs such as cockles and mussels. Using its beak, it is able to break the shells of shelled molluscs. It also has venom to kill its prey. It often brings food to its den to eat later.
All octopuses are venomous. It also defends itself by camouflage to hide in its environment, or by expelling ink and swimming away quickly. The ink makes it difficult for predators to see it.
The Common Octopus has a range of locomotions. It can crawl along the ocean floor. It also swims head first and trails its limbs behind it. It moves by jet propulsion. It has a siphon or funnel (located on the mantle), which is used to help the Octopus breathe, and it is also used for locomotion – it expels a jet of water that propels the Octopus forward.
Training experiments have shown that the Common Octopus can distinguish the brightness, size, shape, and horizontal or vertical orientation of objects. It is considered to be intelligent.
It is a solitary creature.
When the male fertilizes the female’s eggs, it dies. The female lays a string of 10,000 to 70,000 small eggs in a den or rock crevice. The eggs hatch after 160 days. The female looks after her eggs, and does not eat or leave her eggs. She dies soon after her eggs hatch.
The Common Octopus lives for about three years.
Location of photographs: Aquarium de Paris-Cinéaqua, France
Photographer: Martina Nicolls
Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM