View Full Version : The Octopi - Family Octopodidae

09-02-2008, 17:51
One of the most interesting animals you can encounter on the reef is the Octopus. Belonging to the Phylum Mollusca the Octopus have completely lost their shell allowing them to squeeze in a coke bottle, this is a great advantage when you are so tasty and have to hide from predators during the day. That's also whey they are mostly nocturnally active.

They posses acute, colour vision and have eight legs all covered in powerful suckers that provide a continuous stream of sensory information regarding their surroundings. They have the ability to change colour in an instantly, going white when threatened and deep red when excited. They can also manipulate their skin to form different textures allowing them to resemble the reef, or a sponge, blending into the surrounding to go unnoticed.

All octopi have a powerful beak and can inflict a nasty bite. They crunch through shellfish and crabs as a mainstay in their diet. A big pile of broken shells and crab legs are a clue to an octopus lair, they often remove prey to the lair to feast in relative security. Some are also poisonous including the highly venomous Blue Ring Octopus - a tiny species that lives in the warmer waters of the Pacific. The bite from this guy can be fatal in a couple of hours. This species was made famous by the Bond flick "Octo*****".

Octopus display a high degree of intelligence and have been shown to solve complex puzzles. One university began to lose valuable tropical fish test subjects and suspected theft by a student. A recording system was set up to observe the labs and when the tapes were played they showed an octopus removing the lid and climbing out of its tank before making its way to the fish tank and securing a meal after which it returned to its own tank and neatly replaced the lid. This is a natural behaviour as they often close the door of their reef hiding place with a rock and they do cross land naturally also when hunting in tide pools during low tide. They normally move by walking on their tentacles but during flight from a predator they can move incredibly fast using jet propulsion but tire quickly. As a last resort they can fire a cloud of ink to cover their escape. They also have very powerful regeneration abilities and will quickly replace a leg lost in battle.

Incredibly tasty with tomato and onion they are an important food source for many coastal peoples but they do require a tremendous amount of tenderising before cooking. They can be located on the reef during low tide as they release a small stream of bubbles from the lair, I am not sure how.

The people of Tonga have a story that the Octopus once offered a rat a lift on its head from one island to another. When the rat jumped off at its destination it turned and laughed at the Octopus saying, "Ha Ha, look what I left on your head." When the octopus reached up and felt its head it discovered that the rat had taken a dump on the way. It is now said that the Octopus is always trying to catch the rat and in accordance with this story the localsí fish for the Octopus using a device consisting of three separate shells and materials from the coconut tree. When ready this lure has the rudimentary appearance of a rat and it is dangled in the water then jerked up and down. It is very successful at attracting Octopus which go nuts immediately on sighting it and attack it furiously. The fisherman can then life the lure out of the water with the Octopus still attached, it must be actually killed before to make it let go and flashes amazing shades upon attack of its historical foe.

This is a picture of the giant reef octopus Octopus cyanea that I took in Tonga, it has changed its skin colour and texture to match its hiding place..

09-07-2008, 04:44

Cuttlefish's eye