Octopus and cuttlefish are cephalopods (Greek for ‘head-feet’) referring literally to the fact that their feet are attached to their heads. Cephalopods, also molluscs, have large, well developed brains and are widely regarded as the most intelligent of invertebrates.

It’s fascinating to watch an octopus move over a reef, its skin changing instantly to match the colour and texture of the reef and amazingly most cephalopods are believed to be colour blind!

Most octopi and cuttlefish possess chromatophores which are coloured pigments in their skin enabling them to be able to change colouration, patterns and skin texture in milliseconds. Some cephalopods use bioluminescence thought to be used to entice prey while some species use colourful, flashing displays to impress mates, confuse predators or communicate with each other.

Octopus and Cuttlefish are preyed upon by sharks, eels and dolphins while their prey comprises other molluscs, crabs and crayfish. Cephalopods rely on their advanced vision to detect predators and prey. Their life span is usually quite short from six months to just a couple of years or so; depending on the species the male can live for up to three years while females die at around two years shortly after reproducing.

All cephalopods can move by jet propulsion but this is extremely energy consuming. The octopus has no bones so it is highly flexible and manoeuvrable. They have three hearts, their blood is light blue and their bite is poisonous to their prey.

The most poisonous cephalopod is the Blue-Ringed octopus Hapalochlaena lunulata. The venom is the deadly tetrodotoxin – the same toxin produced by pufferfishes. This little creature carries enough venom to kill over twenty adults within minutes. Thankfully this octopus is not aggressive and most incidents with humans occur when they bite following being picked up or stepped on. So if you see this creature, usually grey or beige in colour, starting to display pulsating blue rings - beware!