[vc_row][vc_column][vc_column_text]
Celebrate World Octopus Day with these Facinating Facts
[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column][vc_column_text]Read more about the spectacular Octopus who have a dedicated day to celebrate the species in our marine life blog. Want to know more about being envrironmentally responsible when out on Liveaboards? Click here to read more about How to Be an Environmentally Friendly Diver.[/vc_column_text][vc_separator][/vc_column][/vc_row][vc_row][vc_column][vc_column_text]
Octopus - Cephalopods
[/vc_column_text][vc_column_text]
Octopus are a fascinating marine creature known for their high intelligence and camouflage abilities. There are more than 300 species of Octopus, so they make up a third of the cephalopods species. Octopus can be found in every ocean and can adapt to many different marine environments. Some are adapted to cold water and great depth, over 2,000m. The only environment they cannot live is in freshwater; they need to have salt.
They tend to live close to the surface on the reef, crevices, inside shells or in caves, usually they are solitary. But they can interact with others despite not being able to make or hear sounds.
[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column width=\"1/3\"][vc_single_image image=\"14947\" img_size=\"full\"][vc_column_text]
Most of the octopus subspecies have no internal skeletons and are called Incirrina. So they can squeeze through small spaces and hide in cracks and crevices. There are lesser known subspecies, Cirrata octopus, have an internal shell though and two fins, so it is harder for them to do this.
Octopi were thought to have had a hard shell which they lost in the Jurassic period to make them more agile to evade predators and hunt.
[/vc_column_text][/vc_column][vc_column width=\"1/3\"][vc_single_image image=\"14951\" img_size=\"full\"][vc_column_text]
Octopus come in a range of sizes depending on the species.
The largest is the Giant Pacific Octopus which can reach up to 5m and 50kg, the tentacles can be over 3m in length alone. The smallest species is the Wolfi, at only 2.5cm in length and weighs less than 1 gram. On average they are between 30 and 90cm in length and 3 to 10kg of weight.
[/vc_column_text][/vc_column][vc_column width=\"1/3\"][vc_single_image image=\"14948\" img_size=\"full\"][vc_column_text]
The tentacles are technically arms. Scientists use the term arm when the suckers are along the length - if the sucker is at the tip only then it is a tentacle. They have four pairs of arms, and they contain 60% of the neurons, so some can be used for exploring caves and tasting what they touch, while another can be opening a shell.
[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column][vc_column_text]
Octopi have three different types of movement they can make.
Usually, they walk with their arms along the ocean bottom to save energy. If they need to move a little quicker, they can swim by flexing their arms and body. And if under attack they can expel a water jet from a siphon in their body cavity to move quickly.
An octopus has three hearts; one pumps the blood to the body and organs and two that pump blood to the gills. When they swim the heart pumping the blood to the organs stops so that the octopus can get exhausted quickly. This is one reason they prefer to crawl rather than swim. Octopus blood is blue as they use hemocyanin which is copper based rather than the iron-based haemoglobin to transport the oxygen.
[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column width=\"1/3\"][vc_single_image image=\"14949\" img_size=\"medium\"][/vc_column][vc_column width=\"2/3\"][vc_column_text]
Their skin cells are very specialised and allow them to change colour, reflectivity and opacity rapidly so they can blend into their background. They are very creative with this and can also mimic the behaviour of other animals. They can flex their body to resemble eels lionfish and more.
Octopus are very intelligent and one of the very few marine animals who can demonstrate problem-solving a pattern recognition skills. The can complete mazes and show both long and short-term memory. They learn by observation and are the first invertebrates that have been seen to use tools. Examples of this include using coconut shells for hiding from predators or opening a screw cap jar to get to prey.
[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column][vc_column_text]
Diet
Octopus are carnivores, and their diet includes clams, shrimp and lobster among other items, they tend to hunt at dusk, dawn or even at night. They will cover their prey and envelope it with their arms to pull the prey into the mouth which has a sharp parrot-like beak. They have very powerful jaws and venomous saliva.
[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column width=\"1/2\"][vc_column_text]
Mating
To reproduce the male uses a specialised arm to inseminate the female in her mantle cavity. The females usually lay between 200,000 to 400,000 eggs depending on the species. She will guard them until they hatch and during this time she does not eat. Once the eggs hatch the female’s body begins to shut down, and she will die. The male also dies within a few months of reproducing, so mating for octopus will always lead to death.
The baby octopus larvae drift in plankton-eating other larvae until they mature, during this time they are vulnerable to plankton eaters.
The lifespan of an octopus is short, most will survive for less than one year with a few exceptions. One such exception is the North Pacific giant octopus that can survive for as long as five years.
[/vc_column_text][/vc_column][vc_column width=\"1/2\"][vc_single_image image=\"14950\" img_size=\"full\"][/vc_column][/vc_row][vc_row][vc_column width=\"1/2\"][vc_single_image image=\"14955\" img_size=\"full\"][/vc_column][vc_column width=\"1/2\"][vc_column_text]
Octopus do have several predators these include sharks, eels and dolphins, and their main line of defence is to hide in plain sight. They use their amazing ability to camouflage themselves by changing colour and texture.
When threatened they can release a thick cloud of black ink composed from melanin. This not only obscures the view but also interferes with the attacker\'s sense of smell making them harder to track. If all their defence mechanisms fail, they can lose an arm and regrow it later with no permanent effects.
All octopus are venomous, but only the blue ring octopus is deadly to humans.
At present most octopus are listed as not endangered except for the Cirroctopus hochbergi from New Zealand which is suffering from disappearing habitats due to damage by trawling.
[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column][vc_column_text]Images were provided by Debbie Arriaga @OurOceanImages[/vc_column_text][/vc_column][/vc_row]