Cuttlefish

Cuttlefish, or cuttles, are marinemolluscs of the familySepiidae. They belong to the classCephalopoda which also includes squid, octopuses, and nautiluses. Cuttlefish have a unique internal shell, the cuttlebone, which is used for control of buoyancy. They have large, W-shaped pupils, eight arms, and two tentacles furnished with suckers, with which they secure their prey. They generally range in size from 15 to 25 cm (6 to 10 in), with the largest species, the giant cuttlefish (Sepia apama), reaching 50 cm (20 in) in mantle length and more than 10.5 kg (23 lb) in mass.

Cuttlefish eat small molluscs, crabs, shrimp, fish, octopuses and other cuttlefish. Their predators include dolphins, larger fish (including sharks), seals, seabirds, and other cuttlefish. The typical life expectancy of a cuttlefish is about 1–2 years. Studies are said to indicate cuttlefish to be among the most intelligentinvertebrates. Cuttlefish also have one of the largest brain-to-body size ratios of all invertebrates.

The Greco-Roman world valued the cuttlefish as a source of the unique brown pigment the creature releases from its siphon when it is alarmed. The word for the cuttlefish in both Greek and Latin, sepia, now refers to the reddish-brown color sepia in English.