These are fascinating creatures having two eyes and four pairs of "legs" or "arms" known as tentacles. They have no skeleton which means that they can squeeze through very small spaces. They live in a variety of places in the oceans including coral reefs. They can emit "ink" to cloudy the waters if predators are nearby giving them time to propel themselves into hiding and they can move very swiftly. They have a poison but only one variety is known to be deadly to humans. They have suction cups on their tentacles. Around 300 different species have been identified. They have a relatively short life span ranginf from only six months whereas others can survive up to five years. They are considered to be amongst the most intelligent species of invertebrates (creatures with no backbone) as they have recognition memory. They eat mainly crabs, whelks, clams and also prawns and small fish. In some cultures Octopus is eaten, especially in Japan but also in some Mediterranean regions.