FaunaHub

Cuttlefish (order Sepiida)

Marine invertebrateCephalopodHighly intelligent

Common cuttlefish (Sepia officinalis) hovering over the seabed.

Common cuttlefish (Sepia officinalis).

Image: Diego Delso, CC BY-SA 4.0, via Wikimedia Commons.

Overview

Cuttlefish (order Sepiida) are cephalopod molluscs — relatives of octopuses and squid — and among the most remarkable colour-changers in the animal kingdom. Using thousands of pigment cells and light-reflecting layers in the skin, a cuttlefish can transform its colour and even its texture in a fraction of a second, for camouflage, communication, and dazzling courtship displays. The reference shown here is the common cuttlefish (Sepia officinalis).

They have eight arms and two longer feeding tentacles, distinctive W-shaped pupils, and an internal chambered shell — the cuttlebone — that they use for buoyancy.

Note: there are many cuttlefish species; details vary, so treat general statements as approximate and verify against authoritative sources.

Habitat & Range

Cuttlefish live in coastal and shelf seas across much of the world (though not in the Americas' waters for the true cuttlefish), over reefs, seagrass, sand, and mud. Many move into shallow water to breed and retreat deeper at other times of year.

Diet

Cuttlefish are carnivores that hunt crustaceans, fish, and other small animals. They stalk prey with subtle colour displays, then shoot out two long feeding tentacles with astonishing speed to seize it, drawing it back to the beak. Some appear to use shifting skin patterns to mesmerise prey before striking.

Behavior

Cuttlefish are highly intelligent, with large brains for an invertebrate and well-developed eyes, and they are studied for their learning and problem-solving. Their dynamic skin enables a rich visual “language” of patterns. Like other cephalopods they can jet away from danger and release ink, and they have short lives, typically breeding once before dying.

Human Interaction & Conservation

Cuttlefish are fished and eaten in many regions, and their cuttlebone is a familiar dietary supplement for pet birds. They are also popular subjects for divers and researchers fascinated by their intelligence and colour control. For current status of particular species and fisheries, consult authoritative sources.

More photos of the cuttlefish

Common cuttlefish showing its W-shaped pupils and fin fringe.

Common cuttlefish (Sepia officinalis), Portugal.

Image: Diego Delso, CC BY-SA 4.0, via Wikimedia Commons.

Frequently Asked Questions — Cuttlefish

How do cuttlefish change colour so fast?
Their skin contains huge numbers of tiny pigment-filled cells (chromatophores) that muscles can expand or shrink in an instant, layered over light-reflecting cells. By controlling these together, a cuttlefish can shift colour and pattern almost instantly — and even change skin texture — for camouflage, communication, and courtship.
Is a cuttlefish a fish?
No, despite the name. Cuttlefish are molluscs — specifically cephalopods, the same group as octopuses and squid. They are not fish at all; the "-fish" in the name is a historical quirk of common naming.
What is a cuttlebone?
The cuttlebone is the cuttlefish's internal shell — a porous, chambered structure the animal fills with gas and fluid to control its buoyancy. Washed-up cuttlebones are often collected, and they are commonly given to pet birds as a calcium source.
Are cuttlefish intelligent?
Yes. Cuttlefish have large, complex brains for invertebrates and are studied for learning, memory, and problem-solving. Their elaborate, fast-changing skin displays also point to sophisticated control and communication.

Sources and further reading

Authoritative wildlife references used for general educational context. Conservation status should always be verified against current IUCN Red List data. External links open in a new tab.