Common cuttlefish

The common cuttlefish is a soft sea animal with a big head, large eyes, and a frill of fin around its body. It is not a fish at all — it is a cephalopod, a cousin of the octopus and the squid. It glides over the seabed looking for its next meal.

The cuttlefish is a master of disguise. In the blink of an eye it can change the colour of its skin, and even make it smooth or bumpy, to match the sand or rocks below. It uses this magic to hide from hungry animals, to surprise its dinner, and to send flashing signals to other cuttlefish.

To catch food, the cuttlefish has eight arms and two extra-long tentacles hidden away. When a crab or a little fish comes close, the tentacles shoot out in a flash and pull the meal back to its beak. Common cuttlefish are the biggest kind in British seas and are bold hunters.

Hidden inside its body is a light, chalky shell called a cuttlebone. It is full of tiny air spaces that help the cuttlefish float without sinking. You may have seen a white cuttlebone washed up on a beach, or hanging in a pet bird's cage.

Cuttlefish do not live very long, usually only a year or two. In spring the mother lays clusters of eggs that she stains black with her own ink, so they look like little bunches of grapes. They remain common in many UK seas, and careful fishing and healthy shallow breeding waters help keep them that way.