Cuttlefish or cuttles are colorful masters of camouflage. Many regard these marine mollusks as the “chameleons of the sea.” This is because of their ability to change the colors and textures of their skin in the blink of an eye. What’s weirder is that they do this despite supposedly being colorblind. Out of all the cuttlefish facts out there, that is probably one of the most interesting!
How are they able to change colors so quickly? The cuttlefish’s body is made up of millions of tiny pigment cells called chromatophores. The chromatophores allow the fish t to change its color and pattern at any time. The pigment enters the cuttlefish’s outer skin when it flexes its muscles, allowing it to blend in with its surroundings.
Cuttlefish change the color and texture of their skin to camouflage themselves, attract mates, and communicate with other cuttlefish. The color change may also serve the purpose of stunning prey with quick and debilitating flashes.
Cuttlefish are not only stunning to look at, but they are also very intelligent. In comparison to other invertebrates, the cuttlefish has a relatively high brain-to-body size ratio. According to studies, it can solve problems and manipulate objects to varying degrees. This intellect may be needed to control the extremely complex tentacles and arms, which, like the brain, contain a large number of neurons.
Want to know more? Check out our interesting cuttlefish facts to learn more about these intelligent and colorful animals.
- There are over 100 species of cuttlefish.
- They typically grow to around six to 10 inches or 15 to 25 centimeters in length.
- They mostly live in shallow waters, but some can live in depths of around 2,000 feet or 600 meters.
- The Australian giant cuttlefish, the largest species of cuttlefish, grows to lengths of up to 20 inches or 50 centimeters.
- Cuttlefish fossils are rather rare, but the oldest recorded fossils date back to the Cretaceous period, which is about 145 to 66 million years ago.
- Cuttlefish live in tropical, subtropical, and temperate regions.
- Despite the name, cuttlefish aren’t actually fish.
- Cuttlefish are mollusks.
- They are primarily active at night.
- Cuttlefish are cephalopods, which means they are related to squids, octopuses, and nautiluses.
- You will see them swimming around the seas in Asia, Europe, Australia, and Africa. The seas around the Americas don’t have any cuttlefish.
- They live within coral reefs, muddy areas, kelp forests, and seagrass meadows.
- All cuttlefish belong to the order Sepioidea.
- Female cuttlefish lay their eggs under the cover of shells, seaweed, rocks, and other substrates along the seafloor.
- They are generally solitary animals that only meet up to mate.
- Instead of simple slits or circles, cuttlefish pupils have W-shaped pupils.
- They aren’t endangered animals because of their wide range of habitats. However, the increasing amount of carbon dioxide in the oceans may pose a threat to their kind.
- Cuttlefish fill a wide range of roles within the ecosystem. They are ecologically important, both as consumers and prey animals.
- The term “cuttle” traces back to the Old English word for the animal, cudele, which likely meant “cushion”.
- Scientists are studying their color-changing abilities to make color-changing clothes in the future.
Cuttlefish can change the textures and colors of their skin within one second.
Perhaps one of the most impressive cuttlefish facts is that they can masterfully change the color of their skin in just one second. Because of this, they earned the title “chameleons of the sea”. They can also use their color-changing abilities to startle and ward off potential predators. Impressively, cuttlefish can even do this near-total darkness.
Cuttlefish owe this impressive ability to special cells in their skin that allow them to change color and texture in response to different stimuli.
The outermost cells are the Chromatophores, which contain color pigments. Numerous muscles contract and relax around these cells, which consequently shows differing levels of pigment.
Underneath the chromatophores are the iridophores, which are layers of cells that produce bright shades of blue or blue-green with a metallic sheen.
Finally, there are the leucophores. They lie deeper in the skin than iridophores, and these cells reflect light that matches the background light. The cells assist in camouflage by resembling the colors in the environment.
They can also change their texture and shape to better match their surroundings.
Another impressive ability of the cuttlefish works with their color-changing abilities. They can also match the textures and shapes of the things around them. Cuttlefish do this by extending or retracting their papillae or tiny bumps that surround their skin.
Coupled with their color-changing ability, this ability allows them to swiftly blend in with surrounding sand, rocks, corals, kelps, and other types of substrate. To really seal the deal, they also change the positions of their arms to better match the shapes of surrounding plants.
They are active predators.
Cuttlefish are opportunistic predators that eat whatever is abundant in their territories. The typical cuttlefish diet includes crabs, shrimps, and fish. They may also feed on octopuses, squids, worms, and other marine invertebrates. Although the diets of adults differ by species and region, baby cuttlefish tend to feed mostly on small shrimps.
They have eight arms and two tentacles.
Like squids, cuttlefish have a total of ten limbs — eight arms and two tentacles. If you’re wondering about the difference between arms and tentacles, the main distinction would be the positioning of the suckers.
Arms generally have suckers that run throughout the whole length of the limb, while tentacles typically only have suckers near the end. Cuttlefish use these limbs to grab their prey, and the suckers help prevent escape. In male cuttlefish, one arm called the hectocotylus serves as a reproductive organ. They use the hectocotylus to store and transfer sperm to females.
Cuttlefish use their camouflage to sneak up on prey.
The camouflage of cuttlefish not only hides them from predators, but also from their prey. During the night, they hide and sneak up on potential prey. They move slowly behind their prey to take aim.
Once the prey is within reach, they use their fast-extending tentacles to grab them. For slow-moving prey like crabs, however, they tend to use their eight arms more than their tentacles. After catching their prey, the cuttlefish chomp down on them using their hard, beak-like jaws.
They can also use their color changes to hypnotize their prey.
Among all the cuttlefish facts, perhaps the most impressive one is that cuttlefish can hypnotize their prey using their stunning color changes.
The cuttlefish has the remarkable ability to rapidly flash an array of waving patterns that move down their bodies, and this attracts the attention of unsuspecting prey. This display of colors serves to communicate a “stop and watch me” message, which some may view as “hypnosis”. When the prey stops and watches the flashy display, the cuttlefish can then lunge for its attack.
They can communicate with each other through color changes.
Aside from using their color-changing abilities for camouflage, hunting, and warding off potential predators, cuttlefish can also use their colorful displays to communicate with other cuttlefish. This makes the title “chameleons of the sea” even more apt because chameleons don’t actually use their color-changing abilities for camouflage. Instead, they use it for social signaling!
Cuttlefish have a rather complex visual language and can let other cuttlefish know about their current mood or even future intentions. For example, when two males encounter each other, they show darker colors if they intend to attack, and remain pale if they don’t want any trouble.
Furthermore, they can use their colors to court females. Female cuttlefish can also change their color to gray if they want to mate. Aside from the color changes, they can also communicate via postures and body movements.
Cuttlefish are apparently colorblind.
One of the weirdest cuttlefish facts is that, despite their masterful abilities to control the colors of their skin, cuttlefish are apparently colorblind. They only have one type of color-sensitive protein inside their eyes, in contrast to the humans who have three types. This suggests they can theoretically only see in black and white.
However, researchers suggest that these colorful cephalopods can see color in another way. Cuttlefish have the ability to rapidly change the focus of their eyes and effectively determine the color of an object. The W-shaped pupils of cuttlefish could also enhance this ability and allow them to see colors more vividly.
They can see polarized light.
Although some scientists think that mantis shrimps are the only animals that can truly see polarized light, some postulate that the cuttlefish also shares this ability.
They can use this ability to hunt silvery fish whose scales can polarize light. Moreover, cuttlefish can also polarize light, and this allows them to communicate in secret with other cuttlefish because most other marine creatures can’t detect polarized light.
They can get a 360-degree field of view.
Although their field of view is not 360 degrees at all times, cuttlefish can get a 360-degree field of view by moving their eyes.
This wide field of view allows them to see even objects that are directly behind them, which is especially useful for detecting predators.
Interestingly, these colorful creatures can also move both of their eyes independently, and have depth perception. These abilities make their aim sharp enough to grab their prey with precision.
Cuttlefish blood is blue.
One of the most unusual cuttlefish facts is that they have blue or green-blue blood. Unlike the protein hemoglobin that gives our blood a red color, cuttlefish blood uses hemocyanin to carry oxygen. This protein contains copper, instead of iron, and gives cuttlefish blood a bluish tint.
They have three hearts.
Another one among the most unusual cuttlefish facts is that they have three separate hearts. They have two branchial hearts that pump blood to each of their gills, and one heart which pumps blood throughout the whole body. Because the protein hemocyanin is less efficient in carrying oxygen compared to hemoglobin, the blood of these animals has to pump faster than many other animals.
They produce ink when under attack.
Another one of the most notable defensive strategies of cuttlefish is ink production. When under attack, they can release ink to escape predators. The ink is rich in amino acids and ammonium salts which resemble food and overwhelm predators.
They can release ink in two different ways. The first one is a smokescreen style that can blur the vision of predators while the cuttlefish make their escape. The second one involves releasing an ink blob that’s similar to the size of the cuttlefish. The blob acts as a decoy, tricking predators into thinking it’s food.
Their ink was used to make sepia dye.
Similar to squid ink, cuttlefish ink is also a valuable resource for humans. Humans use their ink to darken and provide flavors to pasta and rice, and it can also act as a dye for various materials.
Most notably, their ink was crucial in the production of sepia dye, which is a long-lasting pigment. The sepia pigment was prominent as a writing ink in the Greco-Roman civilization, and it’s also well known for being an important dye in antique photographs. In fact, the word sepia, comes from the Greek word for cuttlefish.
Cuttlefish can actively control their buoyancy through their internal shells.
One feature of the cuttlefish that makes it unique among cephalopods is that it has an internal structure that’s called a cuttlebone. Despite the name, the cuttlebone isn’t a real bone. It’s the cuttlefish’s internal shell that primarily consists of aragonite.
The cuttlebone contains a lot of pores that provide buoyancy to the cuttlefish, helping them float in the water with ease. Every species of cuttlefish has a distinct cuttlebone that differs from other species in size, shape, texture, and ridges. The largest cuttlebone belongs to the giant Australian cuttlefish, Sepia apama.
Usually, cuttlebones collapse under pressure at depths of 660 to 1,970 feet, or 200 to 600 meters, depending on the species. Because of this, cuttlefish prefer staying in shallow waters.
Cuttlebones are pretty useful for humans, too.
Humans can either harvest cuttlebones from cuttlefish or pick up some that have washed up on the shores. Cuttlebones have plenty of uses for humans, they’re used in the production of polishing powder, antacid, and carving media. Their powder can also be used as additives in toothpaste.
Nowadays, their most prominent use is as a source of dietary calcium for various pets such as birds, reptiles, chinchillas, shrimps, hermit crabs, and snails.
They can move in the water using jet propulsion.
Cuttlefish are quite agile animals that move primarily through swimming. Their streamlined bodies make swimming very efficient.
One of the coolest cuttlefish facts to remember is that, in addition to having fins and arms, cuttlefish can also move through jet propulsion. They fill up their mantle cavity with water and quickly expel it through a siphon, which propels the cuttlefish through the water.
Cuttlefish can control the direction of the siphon, as well as the amount of water they eject. This grants them the ability to propel themselves in different directions and speeds. They use their fins and arms to steer and stabilize themselves.
It’s also interesting to note that cuttlefish can also use this water jet-like ability to uncover prey animals that are hiding in the sand. How’s that for some cool cuttlefish facts?
The flamboyant cuttlefish moves by walking on the seafloor.
Although cuttlefish are typically good at swimming and floating, the flamboyant cuttlefish, also known as Metasepia pfefferi, isn’t too good at these activities. This is because their cuttlebones are quite small, and only allow them to float for a short amount of time. Instead of floating, they just use their arms to walk along the seafloor. They’re the only known cuttlefish species to do so.
Cuttlefish are extremely intelligent animals.
One of the most important cuttlefish facts to remember is that among all invertebrates, they have the largest brains in proportion to their bodies. This grants them rapid reaction times, as well as full control over their color changes and many limbs.
Although they’re not as prominent as octopuses in studies regarding intelligence, cuttlefish are also rather smart animals. Their big brains allow them to have a great learning capacity, and a remarkable ability to solve man-made puzzles and mazes. Interestingly, cuttlefish can also count!
They can display self-control.
Not only are cuttlefish intelligent, but they also have a sense of self-control. In a 2021 study, researchers experimented on cuttlefish — their version of the “marshmallow test” from the 1960s.
The marshmallow test is an experiment wherein young children are presented with a marshmallow, and they could either eat the marshmallow immediately or wait for a few minutes to get two marshmallows.
In the cuttlefish experiment, however, the animals could immediately eat a piece of king prawn, or wait a while to get live grass shrimp, which is their favorite food.
The chamber containing pieces of king prawn would open immediately, while the chamber containing the live grass shrimp would only open if the cuttlefish waited for a while.
Other animals such as mice or birds likely would have only waited for a few seconds, and instead eat the food that’s immediately available to them. The cuttlefish in the experiment, however, resisted the urge to eat for 50 to 130 seconds just to get their favorite food.
They are among the few non-mammals and non-birds that experience REM sleep.
When we sleep, we undergo a phase wherein our eyes move rapidly, our muscle tone decreases, and we begin to dream vividly. Our brains act somewhat awake during this period, with our neurons actively firing away while our bodies remain asleep.
This stage of sleep, rapid eye movement (REM) sleep, is common among birds and mammals and extremely rare among other animals.
The cuttlefish is one of the only non-mammals and non-birds that has REM-like stages in their sleep cycle. Although it’s unknown whether or not cuttlefish can dream, they do twitch their limbs and actively change colors during their REM-like stage of sleep.
Baby cuttlefish can learn even while they’re still inside their eggs.
One of the most interesting cuttlefish facts is that baby cuttlefish can learn even while they’re inside their eggs. Before hatching, young cuttlefish already have fully-developed eyes, and they can observe their environment from inside the transparent eggs.
By learning about their surroundings even before they hatch, they can assess which prey is abundant in their vicinity. For example, if they see an abundance of crabs while they are still in the eggs, they prefer to hunt crabs instead of shrimp after hatching.
Some male cuttlefish pretend to be females to fool dominant males.
Cuttlefish are mainly solitary animals, but they display a more complex social behavior when around other cuttlefish. During courtship, for example, male cuttlefish tend to keep the female cuttlefish to themselves and act aggressively towards other males.
To bypass aggression from rival male cuttlefish, smaller male cuttlefish change their color to the colors of egg-bearing females. The smaller males also hide their fourth arm, (which serves as the male reproductive organ), to better fool the rival males.
Because the dominant male cuttlefish leave the tricky smaller males alone, the smaller male cuttlefish are free to mate with females when the dominant males aren’t looking.
What’s even weirder is that they can change the color of only half of their body so that they show female colors to other males while showing courting male colors to the females.
Females can store and choose which sperm they’ll use to fertilize their eggs.
Among the most obscure cuttlefish facts is that the female cuttlefish can store the sperm of multiple male cuttlefish. During reproduction, males grab the females using their arms.
They mate face to face, with the males depositing spermatophores, or balls of sperm, in a pocket near the mouth of the females. The males may also attempt to get rid of the spermatophores of other males. Females can reproduce with multiple males, and they can choose whose spermatophore they’ll use to fertilize their eggs.
They can carry up to 4,000 eggs.
Cuttlefish reproduce fast. Depending on their body size, female cuttlefish carry anywhere from 150 to 4,000 eggs. After fertilization, the eggs remain in the female’s oviduct for 30 to 90 days before she lays them. Females can lay around 100 to 1,000 fertilized eggs in one spawning. After laying them, she covers them in ink for better camouflage.
Some cuttlefish are venomous.
Although cuttlefish may look like cute and cuddly squid-like creatures, it’s best not to touch them if you see them. That’s because some species of cuttlefish are venomous. The flamboyant cuttlefish, for example, has a venom that’s as potent as that of the blue-ringed octopus, which is among the deadliest marine animals. Now that’s certainly one of the most important cuttlefish facts to remember!
Cuttlefish continue growing indefinitely.
Humans and many other animals stop growing at a certain age, but cuttlefish can grow indefinitely. They grow rapidly early in life, and grow more slowly as they mature, but they never stop growing until they die. Scientists refer to this ability as “indeterminate growth”, and it’s rather common in molluscs, reptiles, and many species of fish.
They don’t live too long.
Although the abilities of the cuttlefish are definitely impressive, they, unfortunately, don’t live for long. Depending on the species, the life expectancy of these animals typically only ranges from one to two years.
Most of them die shortly after reproducing. Before death, they age and deteriorate rapidly. Their eyesight and other body functions begin to fail during the process, which makes them open to attacks from predators. In captivity, cuttlefish breeders typically euthanize dying cuttlefish by using lethal chemicals, or by freezing them.
Cuttlefish have many natural predators.
Although they are indeed successful predators, cuttlefish aren’t that far up the food chain. They have a lot of natural predators, and are important prey of larger carnivores. Their predators include sharks, dolphins, toothed whales, large fish, seabirds, and seals. In some cases, bigger cuttlefish may also eat smaller ones!
They are popular in many cuisines.
In addition to their natural predators, humans also hunt and eat cuttlefish. They are prominent food items near their native habitat and are seen most especially in East Asian and Mediterranean cuisine. Some would describe their meat as more flavorful than squid meat.