Cuttlefish

Cuttlefish are related to both the squids and the octopus. They have an internal shell the cuttlebone. Rarely seen alive by beach goers, the cuttlebones are commonly found stranded, sometimes in their thousands. Cuttlebones are used in bird cages as a source of calcium.

Cuttlefish are relatively flat surrounded by two thin fins. They have eight arms and two long tentacles which have suction pads, that are used for catching prey such as crabs.

Cuttlefish are offshore creatures but come inshore to breed, producing black grape like eggs. Their eggs are washed up on the shore or at the low tide mark amongst seaweed.

They have a phenomenal ability to quickly modify their colour pattern to match their background. Good eyesight plus colour change is used to communicate.

Cuttlefish can move quickly by expelling water at pressure, thus thrusting them backwards. If they come under attack they will shoot out clouds of ink. 

Cuttlebones of three species are found stranded, Sepia officinalis, Sepia orbignyana and Sepia elegans. The larger and whiter sepia officinalis make up the majority. Unless the cuttlefish bones are found soon after the animal has died, it can be difficult to differentiate species, as the identifying features become worn. If fresh cuttlebones are found, the species can be identified by their different posterior shapes.

Common Cuttlefish Sepia officinalis

Can be a large cuttlebone measuring over twelve inches. The dorsal edge of the bone is rounded.

Sepia orbignyana

Another large cuttlefish bone. It can be distinguished from the common cuttlefish by the pointed dorsal end.

Sepia elegans    

A smaller species distinguished by the shape of  the bone's dorsal end.

The cuttlefish bone has a pink tinge.