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“Cuttlefish have three hearts and blue, copper-based blood — just like octopuses.”
The common cuttlefish is a large European cephalopod of coastal ocean waters. It changes color in seconds, hunts shrimp and crabs with two fast tentacles, and uses an internal cuttlebone to fine-tune buoyancy.
Sepia officinalisSepiidaSepiidae
Browse photographs of common cuttlefish across habitat, behavior, anatomy, and life stages.
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Core article
A closer look at habitat, diet, behavior, reproduction, and conservation.
The common cuttlefish (Sepia officinalis) is one of Europe’s most familiar cephalopods — a soft-bodied ocean hunter with eight arms, two long feeding tentacles, and an internal cuttlebone that tunes buoyancy like a scuba vest. In coastal ocean waters from the eastern Atlantic to the Mediterranean, it vanishes into sand with instant camouflage, then flashes color during spring breeding gatherings. Closely related to the octopus, this carnivore packs remarkable eyesight and learning ability into a lifespan that usually lasts only one or two years.
Common cuttlefish belong to the kingdom Animalia, phylum Mollusca, and class Cephalopoda (“head-foot”). Within the order Sepiida and family Sepiidae, the species is Sepia officinalis. Cephalopods also include octopuses, squids, and nautiluses; cuttlefish sit on the sepiid branch defined by the porous internal cuttlebone.
Cephalopods evolved from shelled mollusks hundreds of millions of years ago. Most modern forms reduced or internalized heavy external armor in favor of speed, jet propulsion, and complex nervous systems. The cuttlebone is a remnant of that shelled ancestry, reworked into a chambered buoyancy organ rather than a protective outer shield.
A common cuttlefish’s mantle (the main body) often measures 6 to 18 inches (15–45 cm) in large adults, with weight commonly from about 1 to 9 pounds (0.5–4 kg) depending on age and sex. A continuous fin fringes the mantle, producing the gentle undulating swim that makes the animal look as if it is flying underwater.
Eight short arms surround the mouth, and two longer tentacles shoot out to seize prey before retracting. The beak is sharp and parrot-like; the eyes are large with distinctive W-shaped pupils. Skin contains chromatophores, iridophores, and leucophores controlled by the brain, so color and pattern change in milliseconds for camouflage and communication. Three hearts and copper-based (blue) blood support an active lifestyle in cool coastal seas.
The cuttlebone inside the mantle is lightweight and porous. By adjusting gas and liquid in its chambers, the cuttlefish rises, sinks, or hovers over the seabed with precise control.
Sepia officinalis inhabits the eastern Atlantic Ocean and Mediterranean Sea, ranging from Norway and the British Isles south along Europe and West Africa. It prefers coastal shelf waters — sandy bottoms, seagrass beds, and mixed rock — usually at depths from the shallows to a few hundred meters seasonally.
In spring and summer, adults move inshore to feed and spawn. In autumn and winter many shift to deeper water. They are fully marine and cannot live in freshwater. Favorable ocean nurseries include Portuguese Arrábida coasts, Mediterranean shallows, and similar temperate habitats across their European–African range.
Common cuttlefish are active carnivores. Their diet centers on shrimp, crabs, small fish, and worms. Hunting mixes camouflage and sudden strikes: the animal blends into sand or seagrass, stalks close, then launches two feeding tentacles in a blink to snatch prey and pull it to the beak.
Vision is excellent for detecting motion and contrast, while tentacle clubs lock onto slippery crustaceans. Like other cephalopods, cuttlefish may use gentle probing with the arms to flush prey from cover. When threatened by sharks, seals, or large fish, they can jet away and release an ink cloud that distracts predators.
Outside the breeding season, common cuttlefish are mostly solitary hunters. During inshore spawning aggregations, males display bold zebra-like patterns, chase rivals, and court females with color signals. Some smaller males briefly mimic female patterns to slip past dominant males — a well-studied behavioral tactic.
Intelligence research places cuttlefish among advanced invertebrates. They learn prey preferences, remember solutions, and control intricate skin patterns with fine timing. They are not colonial like social insects or bats; social complexity peaks around mating rather than year-round group living. Compared with the dens of an octopus, cuttlefish more often rest half-buried in sand during the day.
Common cuttlefish are short-lived and typically semelparous — they invest heavily in one breeding season. After mating, females attach clusters of dark, grape-like eggs to algae, rocks, ropes, or wreckage in shallow water. Embryos develop for roughly one to two months depending on temperature.
Hatchlings emerge as miniature cuttlefish already able to hunt tiny prey; there is no prolonged parental care after hatching. Rapid growth follows through the first year. Most individuals live about one to two years before senescence after spawning. Fisheries often target adults during accessible inshore seasons, so year-class strength can swing with ocean conditions and fishing pressure.
(Population and conservation trend data sourced from the IUCN Red List of Threatened Species)
The IUCN Red List evaluates Sepia officinalis as Least Concern. The species remains widespread across European and adjacent Atlantic and Mediterranean waters, though precise global population trends are hard to measure and often listed as unknown.
Natural predators include sharks, dolphins, seals, and large bony fishes. Human impacts center on commercial and artisanal cephalopod fisheries, bycatch, and coastal habitat change affecting seagrass and nursery grounds. Because generation time is short and fecundity is high, populations can rebound if fishing and habitat pressures are managed — but localized overharvest can still deplete stocks quickly in favored spawning bays.
Cuttlefish have three hearts and blue, copper-based blood — just like octopuses.
The white “cuttlebone” sold in bird shops is the animal’s internal buoyancy shell.
They can change skin color and texture in a fraction of a second.
Two long feeding tentacles shoot out to grab prey, then retract under the shorter arms.
Males sometimes disguise themselves with female-like patterns to sneak past rival males.
Common cuttlefish usually live only one or two years and breed once.
Select a question to reveal the answer.
The common cuttlefish (*Sepia officinalis*) is a soft-bodied cephalopod with eight arms, two long tentacles, and an internal cuttlebone. It is one of the best-known cuttlefish of Europe and the Mediterranean.
They live in coastal ocean waters of the eastern Atlantic and Mediterranean, from Norway and the British Isles south to West Africa, usually on sandy or seagrass bottoms.
Cuttlefish are carnivores. They eat shrimp, crabs, small fish, and worms, catching prey with two extendable feeding tentacles.
Cuttlefish have an internal cuttlebone and a broader body with a fin fringing the mantle. Octopuses lack a cuttlebone, have a rounder soft mantle, and usually live in dens among rocks.
The cuttlebone is a lightweight, chambered internal shell that lets the cuttlefish add or remove gas to rise or sink in the water — like a built-in buoyancy vest.
Millions of chromatophore cells expand or shrink under nerve control, instantly shifting patterns for camouflage, hunting, and mating displays.
Yes. Females attach grape-like black or dark eggs to seaweed, rocks, or wrecks in shallow water. Hatchlings look like tiny adults and hunt on their own.
Most common cuttlefish live about one to two years. Adults typically spawn once and then die.
Sepia officinalis is listed as Least Concern, though local populations can be affected by fishing pressure and coastal habitat change.
Yes. When threatened they release a dark ink cloud and jet away, similar to octopuses and squids.
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