# Cuttlefish (*Sepia officinalis*)

> The common cuttlefish (Sepia officinalis) is a soft-bodied marine mollusc found over sandy seabeds and seagrass in coastal seas of the eastern Atlantic and Mediterranean. Despite its name it is not a fish but a cephalopod, related to octopuses and squid, and it can transform its colour and skin texture in a fraction of a second. It grows to about 50 cm including its arms, weighs around 2 kg, and lives only one to two years.

- **Category:** Invertebrate
- **Conservation status (IUCN):** Least Concern
- **Range:** Coastal seas of the eastern Atlantic and the Mediterranean, over sandy and seagrass seabeds.
- **Canonical page:** https://globalanimalguide.org/animals/cuttlefish/
- **Last reviewed:** 2026-07-16

## Scientific classification

- **Kingdom:** Animalia
- **Phylum:** Mollusca
- **Class:** Cephalopoda
- **Order:** Sepiida
- **Family:** Sepiidae
- **Genus:** Sepia

## Facts at a glance

| Attribute | Value |
| --- | --- |
| Scientific name | Sepia officinalis |
| Diet | Carnivore (fish, crabs, shrimp) |
| Habitat | Coastal seas, sandy seabeds, and seagrass |
| Lifespan | 1–2 years |
| Length | Up to about 50 cm (20 in) including arms |
| Top speed | Up to 25 km/h (16 mph) in a jet burst |
| Conservation status | Least Concern (IUCN) |

## Camouflage and colour change

Cuttlefish are among the most accomplished quick-change artists in the animal kingdom, altering their colour, pattern and even skin texture almost instantly. They achieve this using thousands of pigment cells called chromatophores, layered over reflective iridophores and leucophores that bounce light. Remarkably, cuttlefish are colour-blind, yet they still match the hues of their surroundings, probably by sensing light through their skin and detecting polarised light. This mastery lets them melt into a sandy seabed to ambush prey or vanish from a passing predator.

## Hunting and diet

The common cuttlefish is a patient carnivore that preys on fish, crabs and shrimp. It stalks or waits in ambush, then shoots out two long, sucker-tipped feeding tentacles to seize prey in a fraction of a second. Its parrot-like beak, hidden at the base of the arms, breaks apart hard shells, while venom in its saliva helps subdue struggling crustaceans. Some cuttlefish also hypnotise prey with rippling bands of colour that pulse across the body before they strike.

## Movement and the cuttlebone

For everyday travel a cuttlefish swims gracefully by rippling the fin that runs around the edge of its body. When it needs to flee, it draws water into its mantle and jets it out through a funnel, rocketing backwards at bursts of up to 25 km/h (16 mph). Buoyancy is controlled by the cuttlebone, a porous internal shell whose tiny gas-filled chambers let the animal hover effortlessly at any depth. If threatened it can also release a cloud of dark ink to confuse an attacker while it makes its escape.

## Intelligence and senses

Cuttlefish have the largest brain-to-body ratio of almost any invertebrate and show genuine problem-solving ability. Their W-shaped pupils give excellent vision, and experiments suggest they can exercise self-control, waiting for a preferred meal rather than taking an inferior one immediately. They can even remember details of past meals, adjusting their foraging accordingly. This combination of sharp senses and a large brain makes them formidable hunters despite their short lives.

## Reproduction and short life

Cuttlefish live fast and die young, surviving only one to two years. Males compete intensely for females and court them with dazzling displays of shifting colour, while smaller males sometimes disguise themselves as females to sneak past rivals. After mating, the female lays clusters of grape-like eggs, often stained black with her own ink, and attaches them to seaweed or rocks. Both parents die soon after breeding, a life cycle known as semelparity.

## Frequently asked questions

### Is a cuttlefish a fish?

No. Despite the name, a cuttlefish is a cephalopod, a soft-bodied mollusc closely related to octopuses and squid. It swims rather than having fins and gills like a true fish, and it belongs to the invertebrates.

### How do cuttlefish change colour?

They use thousands of pigment sacs called chromatophores in their skin, backed by reflective cells that scatter light. By expanding and contracting these cells they can shift colour, pattern and even skin texture in a fraction of a second.

### How long do cuttlefish live?

Common cuttlefish live only about one to two years. They grow quickly, breed once, and die shortly after laying their eggs.

### What do cuttlefish eat?

Cuttlefish are carnivores that hunt fish, crabs and shrimp. They ambush prey and shoot out two long feeding tentacles to grab it, then break it apart with a hard, beak-like mouth.

### How big do cuttlefish get?

The common cuttlefish reaches about 50 cm (20 in) in length including its arms and weighs up to roughly 2 kg. Some tropical species grow considerably larger, but this is the typical size for the common Atlantic and Mediterranean species.

### Are cuttlefish intelligent?

Yes. Cuttlefish have an unusually large brain for an invertebrate and can solve problems, remember past experiences and even show self-control by waiting for a preferred food. Their intelligence rivals that of some vertebrates.

## Sources

- [IUCN Red List — Sepia officinalis.](https://www.iucnredlist.org/search?query=Sepia%20officinalis&searchType=species)
- [Animal Diversity Web — Sepia officinalis. University of Michigan Museum of Zoology.](https://animaldiversity.org/accounts/Sepia_officinalis/)
- [Wikipedia — Cuttlefish.](https://en.wikipedia.org/wiki/Common_cuttlefish)

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Source: Global Animal Guide (https://globalanimalguide.org/animals/cuttlefish/). Licensed CC BY-NC 4.0 — free for non-commercial reuse with attribution.