Monsters of the Deep Cephalopods are invertebrates - animals without backbones. Usually we think of invertebrates as being small creepy-crawlies, such as insects and spiders, or as worms, slugs, jellyfish, shellfish or crabs.
Cephalopods are the glitziest of the invertebrates.
They can be fast, colourful, beautiful and intelligent. They have large brains, and experiments have shown that they can learn, solve problems, remember and communicate with each other. As well as being colourful and beautiful, octopuses can be fast, intelligent -and deadly. They are quite different in other ways, too. For a start they have a blue blood pigment.