![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/a/a0/Cuttlefish-Cuttlebone2.jpg/640px-Cuttlefish-Cuttlebone2.jpg&w=640&q=50)
Cuttlebone
Hard, brittle internal structure found in all members of the family Sepiidae / From Wikipedia, the free encyclopedia
Dear Wikiwand AI, let's keep it short by simply answering these key questions:
Can you list the top facts and stats about Cuttlebone?
Summarize this article for a 10 year old
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.
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/a/ab/Herklots_1859_I_2_Sepia_officinalis_-_schelp.jpg/220px-Herklots_1859_I_2_Sepia_officinalis_-_schelp.jpg)
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/d/d9/Sepia_officinalis-f.jpg/640px-Sepia_officinalis-f.jpg)
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/1/1f/Turtle_and_Sepia.jpg/640px-Turtle_and_Sepia.jpg)
Cuttlebone is composed primarily of aragonite. It is a chambered structure that the animal can fill with gas or liquid for buoyancy control. On the ventral (bottom) side of the cuttlebone is the highly modified siphuncle; this is the organ with which the cuttlebone is filled with gas or liquid.[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]
When the cuttlefish dies, only the cuttlebone remains and will often wash up on a beach.