Cuttlefish belong to the Class Cephalopoda, which forms part of the Phylum Mollusca. Cephalopods are:
They are the most highly evolved invertebrates and exhibit quite complex behaviour. The Cephalopod group includes the (1) Octopus, (2) Squid, (3) Nautilus and of course, the (4) Cuttlefish.
- soft-bodied marine animals with a large head and a ring of sucker-bearing tentacles
- have three hearts, a systematic heart that pumps blood throughout the body and two brachial hearts that pump blood to the gills
- use a form of jet propulsion to move
- utilize amazing natural camouflage skills to blend in
- can squirt out sepia ink when threatened
- are fast moving and relatively intelligent
Cephalopods are an ancient group that first evolved sometime during the Late Cambrian.
Scientists believe that the ancestor of modern cephalopods was a mollusc that developed an air space within it's shell and worked out a method for regulating the air in it. Predators could be avoided by just floating up off the ocean bottom and the cephalopods could transport themselves over large distances without expended much energy to search of food.
Some scientists also believe that the sub-class Coleoidea which contains the octopus, squid and cuttlefish, diverged from the more primative sub-class Nautiloidea (the Nautilus) as far back as in the Ordivician.