Cuttlebone, also known as cuttlefish bone, is a hard, brittle internal structure (an internal shell) found in all members of the family Sepiidae, commonly known as cuttlefish, within the cephalopods. In other cephalopod families it is called a gladius.

Top and bottom view of a cuttlebone, the buoyancy organ and internal shell of a cuttlefish
Cuttlebone of Sepia officinalis (left to right: ventral, dorsal, and lateral views)
Common cuttlefish Sepia officinalis
Tortoise with cuttlebone
Fossil cuttlebone of the Pliocene species Sepia rugulosa
Fossilised cuttlebone-like gladius of Trachyteuthis[1]

Cuttlebone is composed primarily of aragonite. It is a chambered, gas-filled shell used for buoyancy control; its siphuncle is highly modified and is on the ventral side of the shell.[2] The microscopic structure of cuttlebone consists of narrow layers connected by numerous upright pillars.

Depending on the species, cuttlebones implode at a depth of 200 to 600 metres (660 to 1,970 ft). Because of this limitation, most species of cuttlefish live on the seafloor in shallow water, usually on the continental shelf.[3]

The largest cuttlebone belongs to Sepia apama, the giant Australian cuttlefish, which lives between the surface and a maximum depth of 100 metres.

Human usesEdit

In the past, cuttlebones were ground up to make polishing powder, which was used by goldsmiths.[4] The powder was also added to toothpaste,[5] and was used as an antacid for medicinal purposes[4] or as an absorbent. They were also used as an artistic carving medium during the 19th[6][7] and 20th centuries.[8][9][10][11][12]

Today, cuttlebones are commonly used as calcium-rich dietary supplements for caged birds, chinchillas, hermit crabs, reptiles, shrimp, and snails. These are not intended for human consumption. [13]

Lime productionEdit

As a carbonate-rich biogenic raw material, cuttlebone has potential to be used in the production of calcitic lime.[14]

Jewelry makingEdit

Because cuttlebone is able to withstand high temperatures and is easily carved, it serves as mold-making material for small metal castings for the creation of jewelry and small sculptural objects.[a]

It can also be used in the process of pewter casting, as a mould.

Internal structureEdit

3D visualisation of a Sepia cuttlebone by industrial micro-computed tomography
Flight through the corresponding tomographic image stacks

See alsoEdit


  1. ^ Jewelers prepare cuttlebone for use as a mold by cutting it in half and rubbing the two sides together until they fit flush against one another. Then the casting can be done by carving a design into the cuttlebone, adding the necessary sprue, melting the metal in a separate pouring crucible, and pouring the molten metal into the mold through the sprue. Finally, the sprue is sawed off and the finished piece is polished.


  1. ^ Fuchs, D.; Engeser, T.; Keupp, H. (2007). "Gladius shape variation in coleoid cephalopod Trachyteuthis from the upper Jurassic nusplingen and Solnhofen plattenkalks" (PDF). Acta Palaeontologica Polonica. 52 (3): 575–589.
  2. ^ Rexfort, A.; Mutterlose, J. (2006). "Stable isotope records from Sepia officinalis — a key to understanding the ecology of belemnites?". Earth and Planetary Science Letters. 247 (3–4): 212–212. Bibcode:2006E&PSL.247..212R. doi:10.1016/j.epsl.2006.04.025.
  3. ^ Norman, M.D. (2000). Cephalopods: A world guide. Conch Books.
  4. ^ a b "Uses for cuttlebone. The time when it was used as a medicine (1912)". Retrieved 21 January 2016.
  5. ^ "Do you know this?". The World's News. 8 July 1950. p. 26. Retrieved 21 January 2016.
  6. ^ "Wesleyan anniversary". Portland Guardian and Normanby General Advertiser. 17 October 1872. p. 2. Retrieved 21 January 2016.
  7. ^ "Carnival at Norwood". Evening Journal. 24 October 1898. p. 3. Retrieved 21 January 2016.
  8. ^ "Eleanor Barbour's pages for country women". Chronicle. 16 July 1942. p. 26. Retrieved 21 January 2016.
  9. ^ "Note book cuttlefish". The Register News-Pictorial. 17 May 1930. p. 3S. Retrieved 21 January 2016.
  10. ^ "Models from cuttle-fish". The Age. Interesting Hobbies. 30 June 1950. p. 5S. Retrieved 21 January 2016.
  11. ^ "Back to semaphore celebrations". Port Adelaide News. 13 December 1929. p. 3. Retrieved 21 January 2016.
  12. ^ "Out among the people". The Advertiser. 12 May 1943. p. 6. Retrieved 21 January 2016.
  13. ^ Norman, M.D.; Reid, A. (2000). A Guide to Squid, Cuttlefish, and Octopuses of Australasia. CSIRO Publishing.
  14. ^ Ferraz, E.; Gamelas, J.A.F.; Coroado, J.; Monteiro, C.; Rocha, F. (20 July 2020). "Exploring the potential of cuttlebone waste to produce building lime". Materiales de Construcción. 70 (339): 225. doi:10.3989/mc.2020.15819. ISSN 1988-3226.