Animal
Common cuttlefish
The common cuttlefish is a sea animal that can change color in a flash. It has eight arms and two long tentacles. A wavy fin runs along each side of its body.
The common cuttlefish lives in the eastern Atlantic Ocean and the Mediterranean Sea. It is a relative of octopuses and squids, and it is a champion of camouflage: it can change its colors and patterns in moments to match the sea floor, and it floats using a light, hollow shell inside its body called a cuttlebone.
Sepia officinalis is a demersal cephalopod of the eastern Atlantic and Mediterranean, a model species for research on adaptive camouflage, and one of the most commercially important cephalopods. It lives 12 to 24 months, migrates seasonally between inshore spawning grounds and deeper shelf waters, and controls its buoyancy with a porous internal cuttlebone.
Photo: Diego Delso, CC BY-SA 4.0, via Wikimedia Commons
Meet the common cuttlefish
The cuttlefish is a soft sea animal with big eyes.
It has eight arms and two long tentacles. A wavy fin runs along each side of its body. It can change its colors very fast!
The common cuttlefish is a cephalopod, like octopuses and squids. It has a broad, slightly flat body, eight arms, two long tentacles for catching food, and a fin like a frilly skirt that runs along each side of its body.
Cuttlefish are famous for changing color. In a moment, a cuttlefish can turn pale, dark, striped or spotty, often matching the sea floor around it. Inside its body is a light, chalky shell called a cuttlebone, which helps it float.
Sepia officinalis (order Sepiida, family Sepiidae) is a broad, somewhat flattened cephalopod, oval in cross section, with paired fins running from behind the head to the tip of the body, eight arms and two long tentacles (MarLIN). Mantle length reaches about 45 centimeters (MarLIN) to 49 centimeters (SeaLifeBase), and weights up to 4 kilograms are reported in temperate waters.
It is a model organism for studying adaptive camouflage: research by Roger Hanlon and colleagues has shown that it uses three main body pattern types, Uniform, Mottle and Disruptive, chosen from visual cues in its surroundings. It is also one of the most important cephalopods in fisheries, highly valued as food in Japan, Korea, Italy and Spain (SeaLifeBase).
Quick facts
- Group
- Invertebrate
- Length
- up to 45 cm
- Weight
- up to 4 kg
- Lifespan in the wild
- 1 to 2 years
Where it lives
Common cuttlefish live in the sea near Europe and North Africa.
They like sandy and muddy sea floors. In summer they swim close to the shore.
Common cuttlefish live in the eastern Atlantic Ocean, from Norway and the British Isles down to West Africa, and all around the Mediterranean Sea. They live near the bottom, over sand and mud, from shallow water down to about 200 meters, but usually less than 100 meters deep.
They move with the seasons. In spring and summer they come close to the shore to breed. In autumn and winter they move out to deeper water, around 100 meters down.
The IUCN assessment lists the species from Norway, Sweden, Denmark and the North Sea countries, the British Isles, France, Spain and Portugal (including Madeira and the Canary Islands), around the Mediterranean from Spain to Türkiye, the Levant, Egypt and North Africa, and along the Atlantic coast of Morocco, Western Sahara, Mauritania and Senegal. SeaLifeBase gives southern Norway and the Shetlands south to northwestern Africa, with strays in the Baltic.
It is a neritic, demersal species of sandy and muddy bottoms, typically to 100 meters and recorded to about 200. SeaLifeBase describes seasonal migrations between inshore waters in spring and summer and shelf grounds at around 100 meters in autumn and winter; the IUCN classes it as a full migrant.
Continents
Did you know?
A cuttlefish's eye has a pupil shaped like a W.
In bright light, a common cuttlefish's pupil is shaped like a curvy letter W, as in the photo on this page. In the dark it turns round.
The slit pupil takes a W shape in bright light and is circular in darkness; Mäthger et al. (2013) found the W shape evens out a vertically uneven light field, cutting glare from above.
Where can you find this animal?
- Lives here naturally · Countries and seas named by a scientific source
- Sightings recorded · Records of wild sightings (GBIF)
Lives here naturally · Countries and seas named by a scientific source
Coastal and shelf waters of the eastern Atlantic from Norway to Senegal, and all around the Mediterranean Sea, as listed in the IUCN assessment. The map shades whole countries; cuttlefish live only in the sea off their coasts.
Places: Norway, Sweden, Denmark, Germany, Netherlands, Belgium, UK, Ireland and 21 more places.
Source: iucn-red-list · checked October 2026
Sightings recorded · Records of wild sightings (GBIF)
Counts of GBIF records of wild observations (human and machine) and preserved specimens. Records include introduced populations, vagrants, escaped or released animals and misidentifications, so a country with records is not necessarily part of the native range.
Wild sightings have been recorded in Netherlands, France, Spain, UK, Portugal, Germany, Italy, Croatia and 50 more places.
Source: gbif · checked October 2026
Range maps show where scientists say an animal lives, often country by country. An animal may live in only part of a country shown, and sightings records can include animals that wandered far from home.
What it eats
Cuttlefish eat crabs, shrimp and small fish.
They shoot out two long tentacles to grab their food. Then their arms hold it.
Common cuttlefish eat crabs, shrimp, small fish and small mollusks, and sometimes even other cuttlefish.
They hunt with a surprise attack. Many cuttlefish hide in the sand during the day and ambush prey that comes close. When the moment is right, two long tentacles shoot out very quickly and grab the prey with their sucker-covered tips. Then the eight arms hold the food while the cuttlefish eats it.
SeaLifeBase lists small mollusks, crabs, shrimps, other cuttlefishes and juvenile demersal fishes in the diet and notes that cannibalism is common. From hatchlings to adults, cuttlefish show light-induced burying: most hide in sand during the day, and prey is often ambushed from there.
Prey capture relies on the two tentacles, cylindrical and muscular, which can be elongated very quickly and end in a tentacular club bearing five to six rows of suckers (MarLIN). Once the prey is seized, the eight arms, specialized for grasping, take over.
Did you know?
Baby cuttlefish hide in the sand, just like grown-ups.
Even newly hatched cuttlefish, only 7 to 8 millimeters long, bury themselves in the sand during the day.
Light-induced burying is shown from hatchlings to adults; hatchlings measure about 7 to 8 millimeters in total length.
Color, camouflage and a floating bone
A cuttlefish can change color to match the sand or the rocks.
Inside its body is a light, holey bone. It helps the cuttlefish float.
A cuttlefish's skin can show many patterns. Scientists sort its camouflage into three main types: Uniform, all one color; Mottle, small blotches; and Disruptive, bold patches that break up its outline. It chooses a pattern by looking at what is around it.
Inside, the cuttlebone works like a hard float. It is made of a chalky mineral, but it is about 93 percent empty space, divided into tiny chambers. That makes it very light and strong at the same time. Look at the photo: you can see the cuttlefish's big eye with a W-shaped pupil.
Allen and colleagues (2010) offered cuttlefish choices of substrates that evoke the three main body pattern types and found no strong preference except where the animals could bury; given conflicting cues on each side, they produced mixed patterns. Buresch and colleagues (2011) showed that cuttlefish masquerade as a nearby 3D object rather than match the sea floor when the object is high-contrast against a lower-contrast background.
The cuttlebone is an internal aragonite shell with about 93 percent porosity that serves as a hard buoyancy tank. Yang and colleagues (2020) found that its chambered wall-and-septa structure combines high stiffness with energy absorption and withstands water pressure of about 20 atmospheres in this species.
From sea grapes to cuttlefish
A mother cuttlefish lays eggs that look like little black grapes.
She sticks them to seaweed and shells. Tiny cuttlefish hatch out, and they already look like small grown-ups.
Cuttlefish breed in shallow water. A male courts a female with displays and guards her from other males. The female then lays her eggs in clusters that look like bunches of grapes, attached to seaweed, shells and other objects. Each egg is about a centimeter across and stained black with ink.
The eggs take 30 to 90 days to hatch, faster in warmer water. The hatchlings are only 7 to 8 millimeters long, but they already bury themselves in the sand like adults. A cuttlefish lives only one to two years.
SeaLifeBase describes elaborate, ritualized courtship with visual displays and mate guarding, with spawning in shallow water, optimally at 13 to 15 °C. MarLIN notes that the male uses a modified arm to transfer sperm to the female's buccal area, around her mouth. Eggs 8 to 10 millimeters across, blackened with ink, are attached in grape-like clusters to seaweed, shells, debris and other substrates.
Development takes 30 to 90 days depending on temperature. Hatchlings measure about 7 to 8 millimeters in total length and already show the light-induced burying behavior of adults. The whole life cycle in the wild lasts 12 to 24 months, and adults usually die soon after breeding (SeaLifeBase).
Hiding, hunting and resting
Cuttlefish hide in the sand in the daytime.
When they are scared, they can change color very fast. They even seem to have a kind of sleep!
Cuttlefish are experts at not being seen. Many bury themselves in the sand during the day, and they can change color very quickly, especially when they feel threatened.
Scientists have also seen cuttlefish rest in a sleep-like state. While resting, their colors change, their arms twitch and their eyes move quickly. That might be like the stage of sleep called REM sleep in people, but scientists are still finding out.
MarLIN describes very rapid color change, especially under threat, and the ability to take on the color or pattern of the background. Hanlon and colleagues showed that camouflage choices respond to visual cues such as contrast, and that cuttlefish resemble 3D objects in some contexts.
Frank and colleagues (2012), cited by MarLIN, observed a periodic sleep-like state lasting on average 135 seconds during inactivity, with body-color changes, arm twitching and rapid eye movements, which could indicate a state similar to REM sleep. MarLIN also notes the claim that cuttlefish have one of the largest brain-to-body ratios of any invertebrate.
Did you know?
Cuttlefish eggs look like bunches of little black grapes.
Cuttlefish eggs are stained black with ink and laid in bunches that look like grapes, stuck to seaweed and shells.
Eggs 8 to 10 millimeters across, blackened with ink, are attached in grape-like clusters to seaweed, shells and debris (SeaLifeBase).
Cuttlefish and people
Lots of people catch cuttlefish to eat.
Scientists keep watch to make sure there are still plenty in the sea.
The IUCN Red List lists the common cuttlefish as Least Concern, but that check was done in 2009 and needs updating, and no one knows whether numbers are going up or down.
Cuttlefish are caught for food in many countries. In some places, such as the Mediterranean, they have been fished heavily in recent years. Changes in the ocean caused by a changing climate could also affect where they live.
The IUCN assessed Sepia officinalis as Least Concern (assessed 2009, published 2012, flagged as needing an update), with an unknown population trend. Listed threats are fishing and harvesting and climate-driven habitat shifting and alteration.
SeaLifeBase describes it as one of the most commercially important cephalopods and notes that it has been heavily fished in recent years, for example in the Mediterranean. SeaLifeBase also notes its potential for aquaculture.
IUCN Red List
How is the common cuttlefish doing in the wild?
- Least Concern (this animal)
- Near Threatened
- Vulnerable
- Endangered
- Critically Endangered
- Extinct in the Wild
- Extinct
Least Concern
Not at risk of disappearing from the wild right now.
Amazing facts
-
Cuttlefish eggs look like bunches of little black grapes.
Cuttlefish eggs are stained black with ink and laid in bunches that look like grapes, stuck to seaweed and shells.
Eggs 8 to 10 millimeters across, blackened with ink, are attached in grape-like clusters to seaweed, shells and debris (SeaLifeBase).
-
A cuttlefish's eye has a pupil shaped like a W.
In bright light, a common cuttlefish's pupil is shaped like a curvy letter W, as in the photo on this page. In the dark it turns round.
The slit pupil takes a W shape in bright light and is circular in darkness; Mäthger et al. (2013) found the W shape evens out a vertically uneven light field, cutting glare from above.
-
Baby cuttlefish hide in the sand, just like grown-ups.
Even newly hatched cuttlefish, only 7 to 8 millimeters long, bury themselves in the sand during the day.
Light-induced burying is shown from hatchlings to adults; hatchlings measure about 7 to 8 millimeters in total length.
-
Cuttlefish seem to have a kind of sleep.
Scientists have seen resting cuttlefish twitch their arms, change color and move their eyes quickly, in a sleep-like state.
Frank et al. (2012) described a periodic sleep-like state averaging 135 seconds, with rapid eye movements that could indicate a REM-like state.
Words to know
- camouflage
- colors or patterns that help an animal blend in with its surroundings
- cuttlebone
- the light, chambered shell inside a cuttlefish that helps it float
- tentacle
- a long, bendy body part used to grab things
- mantle
- the main part of a cuttlefish's or octopus's body
- cephalopod
- a sea animal with arms around its head, like an octopus, squid or cuttlefish
- buoyancy
- the ability to float in water
Discovery challenge
-
What helps a cuttlefish float?
What is the cuttlebone used for?
What is the main function of the cuttlebone?
- Biting food
- Floating at the right depth
- Breathing air
Show the answer
Floating at the right depth
Its light cuttlebone helps it float.
The cuttlebone is a light, chambered shell that helps the cuttlefish float.
It is a porous aragonite buoyancy tank, about 93 percent empty space.
-
What do cuttlefish eggs look like?
What do common cuttlefish eggs look like?
How are Sepia officinalis eggs laid?
- Bunches of black grapes
- White ping-pong balls
- Long strings of jelly
Show the answer
Bunches of black grapes
They look like little black grapes.
They are stained black with ink and laid in grape-like bunches.
Ink-blackened eggs of 8 to 10 millimeters in grape-like clusters attached to substrates.
-
What does a cuttlefish use to grab its food?
Which body parts shoot out to grab a cuttlefish's prey?
Which appendages make the initial strike in prey capture?
- Its fins
- Its eyes
- Two long tentacles
Show the answer
Two long tentacles
Two long tentacles grab the food.
Two long tentacles shoot out fast and grab the prey; the arms then hold it.
The two tentacles, rapidly elongated, with suckered clubs; the arms then grasp the prey.
-
How long does a cuttlefish live?
About how long does a common cuttlefish live in the wild?
What is the typical length of the life cycle of Sepia officinalis in the wild?
- About 100 years
- One to two years
- One week
Show the answer
One to two years
Only one or two years.
About one to two years.
12 to 24 months; adults usually die soon after breeding.
Places where you might see it
-
Watch
Country
Portugal
Portugal is a country on the Atlantic coast of the Iberian Peninsula in southwestern Europe, with Spain as its only land neighbor. It also includes the Azores and Madeira islands far out in the ocean. About 11.4 million people lived there at the start of 2026, and its capital is Lisbon, on the Tagus River.
-
Watch
Country
Spain
Spain covers most of the Iberian Peninsula in southwestern Europe. Its middle is a high, flat plateau, the Pyrenees mountains stand between it and France, and almost 50 million people live there, with Madrid as the capital.
Explore next
-
Watch
3D
Animal
Common octopus
The common octopus is a soft-bodied mollusc with eight sucker-lined arms. It lives in coastal waters, hides in a den by day, hunts snails and clams at night, and can change its color, skin texture and shape to vanish against rocks or sand. It lives only one to two years.
-
Watch
Animal
Giant squid
The giant squid is one of the biggest animals without a backbone. Most of its length is two very long, stretchy feeding tentacles. It lives deep in oceans around the world, and it is so hard to find that the first photos of a living one in the wild were taken only in 2004.
-
Watch
Animal
Mimic octopus
The mimic octopus is a long-armed, brown-and-white octopus that lives on sandy sea floors in Southeast Asia. Scientists first filmed it in 1998 and were amazed: it changes its shape, colors and movements to look like other animals, including a flatfish, a lionfish and a sea snake.
-
Watch
Country
Portugal
Portugal is a country on the Atlantic coast of the Iberian Peninsula in southwestern Europe, with Spain as its only land neighbor. It also includes the Azores and Madeira islands far out in the ocean. About 11.4 million people lived there at the start of 2026, and its capital is Lisbon, on the Tagus River.
-
Watch
Country
Spain
Spain covers most of the Iberian Peninsula in southwestern Europe. Its middle is a high, flat plateau, the Pyrenees mountains stand between it and France, and almost 50 million people live there, with Madrid as the capital.
-
Watch
Animal
Greater blue-ringed octopus
The greater blue-ringed octopus is a small octopus that lives among rocks and reefs in the western Pacific. Most of the time it hides, but when it is bothered, about 60 blue rings flash on its skin. The bright rings are a warning, and they tell us this is an animal to watch, never to touch.
-
Watch
Animal
American lobster
The American lobster is a big crustacean that lives on the rocky sea floor of the northwest Atlantic Ocean. It has two very different claws, one for crushing and one for tearing, and it must climb out of its hard shell again and again to grow.
-
Watch
3D
Animal
Antarctic krill
Antarctic krill are small, shrimp-like crustaceans about 6 centimeters long that live in the icy Southern Ocean around Antarctica. They gather in enormous swarms, and almost all the bigger animals of the Antarctic, from penguins to blue whales, depend on them for food.
For parents & teachers
What children will learn
- Describe how cuttlefish use camouflage and the three main pattern types.
- Explain how the cuttlebone helps a cuttlefish float.
- Describe the cuttlefish life cycle, from egg clusters to hatchlings that look like adults.
- Describe how people fish for cuttlefish and the threats the species faces.
Recommended ages: 3 to 17 · About 15 minutes
Talk about it
- Why might a cuttlefish choose one camouflage pattern on sand and another near rocks?
- How is a cuttlebone like a life jacket, and how is it different?
- What could happen to cuttlefish numbers if too many were caught before they bred?
Try at home or in class
- Make three paper cuttlefish: one plain, one spotty and one with big bold patches. Place them on different backgrounds and see which is hardest to spot.
- Float a dry sponge and a pebble in a bowl of water to compare how something full of tiny air spaces floats.
Key vocabulary: camouflage, cuttlebone, tentacle, mantle, cephalopod, buoyancy
Where these facts come from
- The IUCN Red List of Threatened Species , International Union for Conservation of Nature (IUCN terms of use (no redistribution of Red List data or range maps))
- GBIF Backbone Taxonomy and GBIF Occurrence Search , Global Biodiversity Information Facility (CC0 1.0 (backbone); occurrence counts are facts derived from records under CC0, CC BY and CC BY-NC)
- Sepia officinalis (Barratt & Allcock 2012) , IUCN Red List of Threatened Species
- Common cuttlefish (Sepia officinalis) , MarLIN, Marine Biological Association of the UK
- Sepia officinalis Linnaeus, 1758 , SeaLifeBase
- Cuttlefish dynamic camouflage: responses to substrate choice and integration of multiple visual cues (Allen et al. 2010), abstract , PubMed, US National Library of Medicine
- The use of background matching vs. masquerade for camouflage in cuttlefish Sepia officinalis (Buresch et al. 2011), abstract , PubMed, US National Library of Medicine
- The W-shaped pupil in cuttlefish (Sepia officinalis): functions for improving horizontal vision (Mäthger et al. 2013, Vision Research 83: 19–24), abstract , PubMed, US National Library of Medicine
- Mechanical design of the highly porous cuttlebone: A bioceramic hard buoyancy tank for cuttlefish (Yang et al. 2020, PNAS 117: 23450–23459), abstract , PubMed, US National Library of Medicine
- Wikidata , Wikimedia Foundation (CC0 1.0)
- Wikimedia Commons , Wikimedia Foundation (Per file: Public domain, CC0, CC BY or CC BY-SA only (credited on each page))
Checked, not yet human-reviewed. Last updated October 28, 2026. Spotted a mistake? Tell us.