A bit more Nature

A bit more Nature, close up.

At this time of the year we often get cuttlebones washed up on the beach, sometimes in their hundreds. Cuttlebone is a hard, brittle internal structure found in those free swimming marine molluscs commonly known as cuttlefish.

Cuttlebone is a chambered, gas-filled shell composed primarily of aragonite, a form of calcium carbonate. The cuttlebone in the photograph has been snapped in half, revealing the internal structure which consists of delicate horizontal layers connected and supported by numerous upright pillars. The structure is best seen through the virtual microscope. The cuttlefish can regulate the relative amounts of gas and liquid within the cuttlebone thereby adjusting its buoyancy and its position in the water column.

In the past, cuttlebones were ground and used as a polishing powder, including in toothpaste, and as an antacid to aid the digestion. Today, you are most likely to come across a cuttlebone in a Budgerigar cage where they are used to provide calcium to the bird's diet.