Free tools Windows power users keep installed
One-click scans. No signup required.
Some links on this page are affiliate links: if you buy through them we may earn a commission, at no extra cost to you.
The broadclub cuttlefish (Sepia latimanus) appears to make its final approach to crabs harder to detect by sending dark stripes down its head and arms. In a laboratory experiment, shore crabs reacted less often to simulated predator approaches with downward-moving stripes than to comparable unstriped or stationary-striped approaches. The results support a form of motion camouflage—but they do not prove that every wild prey animal is fooled or that the display increases hunting success in nature.
What does the broadclub cuttlefish do when it approaches a crab?
In the close-range phase of a hunt, the cuttlefish adopts a distinctive posture: its head becomes pale, six arms reach forward in a cone, and the remaining two extend sideways. It then sends high-contrast dark stripes down its head and arms. The display is not simply a color change. Its defining feature is that the pattern moves, creating a pronounced downward visual signal while the animal advances.
As an Amazon Associate I earn from qualifying purchases.
Researchers documented the display in wild hunting sequences and analyzed how it might affect a prey animal’s perception of an approaching predator. Their study, published in Science Advances, describes the behavior as adaptive motion camouflage: the cuttlefish may use one movement pattern to interfere with another visual cue that would otherwise reveal its approach.
The display is used during the final part of the approach, not as a general-purpose pattern that the study establishes is used in every situation. The posture may contribute as well as the stripes. A flattened, horizontally elongated shape could reduce the visual expansion associated with an advancing animal, and the laterally extended arms may obscure fin movement from a crab’s viewpoint. Those are proposed parts of the explanation, rather than separately proven effects.
Popular on Amazon
- Dog multivitamins chewable for skin & coat : Dog multivitamin is rich in Omega-3 fatty acids and vitamin E,which can relieve skin allergies,dryness,itching and other problems.Multivitamin for dogs nourishes skin follicles.Long-term consumption of dog vitamins multivitamin can make dog hair stronger and smoother,and reduce coat loss.The COQ10 in dog multivitamin chewable can resist oxidation and delay cell aging.Dogs with skin injuries can eat dog vitamins and supplements to promote wound healing
- Dog multivitamin relieves joint inflammation: Dog vitamins for hip and joint can supplement high-quality MSM, glucosamine, and chondroitin sulfate to promote cartilage development and repair. Long-term consumption of dog multivitamins chewable can enhance the elasticity and toughness of joint cartilage, improve joint flexibility, and move more freely. Dog multivitamin chews can reduce joint friction and relieve joint pain. Dog vitamins and supplements can prevent and improve dog joint problems
- Dog multivitamin chews are good for the gut: Vet-endorsed formula dog vitamins and supplements made from natural ingredients.Dog vitamins multivitamin chewables contain a rich blend of probiotics to support intestinal and digestive health.Dog vitamins for small dogs can regulate the balance of intestinal flora,help calcium absorption,and promote bone development.Dog multivitamins chewables improve energy metabolism,converting food into energy, making dogs more energetic in their daily activities
- Dog multivitamin chews protect overall health:Senior dog vitamins and supplements help improve blood circulation and prevent cardiovascular disease.Dog multivitamins chewable support normal liver function,promote liver detoxification,and improve negative mood.For dog with heart problems and older dog,taking dog vitamins and supplements in moderation is an auxiliary health care measure.Dog vitamins multivitamin helps enhance white blood cell activity,improve immunity,prevent infection and disease
- Dog multivitamins chewable promote brain development: The DHA in krill oil in multivitamin for dogs is an important component of the brain and retina. Dog vitamins and supplements can improve dog cognitive ability. When training puppies to learn basic commands, puppies who are properly supplemented with dog vitamins multivitamin will behave more intelligently and improve memory.Dog supplements & vitamins can prevent and relieve eye problems such as dry eyes and tear stains, and keep eyes healthy
How can moving stripes hide an approaching predator?
A predator advancing toward an observer can create a visual pattern known as radial expansion, or looming: the image grows outward from a central point as the predator gets closer. For a crab, that expanding pattern may act as a warning that something is approaching. The cuttlefish’s downward-moving stripes could make a different, stronger motion signal stand out instead.
The idea is not that stripes make the cuttlefish invisible. The display can look conspicuous to a human observer, especially against a natural background. Instead, the authors propose that the rhythmic downward motion competes with or masks the radial expansion cue in a crab’s motion-sensitive visual system. If the prey’s attention or motion processing is dominated by the downward signal, the approach may be less likely to trigger the response associated with an oncoming predator.
Do these 3 things before closing this tab:
1Clear out junk files and repair common Windows errors2Scan for outdated or missing drivers - takes under a minute3Repair Windows errors before they cause bigger problemsThis distinction matters: camouflage does not always mean matching the background or disappearing from view. A pattern can be visible yet still make an animal’s movement harder to interpret. In this case, the proposed advantage is about confusing the direction and structure of motion, not simply blending in through color.
The University of Bristol’s summary of the research quotes lead author Dr Matteo Santon: “To our eyes this dynamic display looks very conspicuous, standing out strongly from the background, but it is exploiting the effect of the strong dynamic motion cues produced by the rhythmic passing stripes to deceive the prey.” The quotation captures the contrast between what a human may notice and the particular visual cues the researchers think matter to a crab.
Also popular on Amazon
- Joint Health Supplement for Dogs: Cosequin is the #1 vet recommended retail joint health supplement brand, supporting joint health in dogs for over 25 years
- Contains Glucosamine for Dogs: Cosequin contains glucosamine hydrochloride (FCHG49) and sodium chondroitin sulfate (TRH122), plus methylsulfonylmethane (MSM). This unique combination of ingredients supports healthy joints
- For Any Breed or Size: Whether you have a young or senior dog, a small or large breed, Cosequin helps support their joint health
- Tasty Chews for Daily Use: Cosequin comes in a tasty chewable tablet, making daily administration easy and convenient
- Exceptional Quality: Cosequin is backed by science, undergoing thorough quality inspections to ensure your dog receives a safe, high-quality product. It is manufactured in the United States with globally sourced ingredients
What did the crab experiment actually test?
Researchers presented shore crabs (Carcinus maenas) with expanding visual stimuli designed to represent an approaching predator. They compared three kinds of stimulus: one without stripes, one with stationary stripes, and one with stripes moving downward. Crabs were more likely to react to the high-contrast unstriped and stationary-striped stimuli than to the stimuli with downward-moving stripes.
The comparison helps separate the effect of moving stripes from the mere presence of a striped pattern. If stripes alone were enough to reduce responses, the stationary-striped stimulus should have had a similar effect. Instead, the lower response was associated with stripes moving downward. That result supports the idea that the direction and dynamics of the pattern matter.
The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →The experiment provides evidence that the moving stripes can reduce crab responses to an expanding visual cue under the laboratory conditions tested. It does not show that the crabs were completely unable to see the stimulus, explain every part of their response, or establish that all prey species interpret the pattern in the same way. The study’s crabs may also have been naïve to predators that use dynamic skin patterns.
How fast and how close are the stripes used?
The field analysis recorded 28 passing-stripe displays from at least 17 cuttlefish. The animals used the display at an average distance of 97.8 ± 32.3 centimeters from their prey, and the average stripe frequency was 2.2 ± 0.7 hertz. These are averages from the observed hunting sequences, not fixed settings that every cuttlefish uses on every approach.
Also popular on Amazon
- 8-in-1 Formula - Zesty Paws Multifunctional Bites are functional supplement chews with premium ingredients that support physical performance, antioxidants, hip & joint, heart, immune, skin, liver, & gut health for dogs of all ages, breeds, and sizes.
- Skin Health & Antioxidants – For animals with sensitive skin, this formula contains Cod Liver Fish Oil and Vitamin E to help maintain normal moisture and CoQ10 to help reduce oxidative stress.
- Hip, Joint & Performance Support - Each dog chew features OptiMSM, a premium form of MSM for muscular support, which works synergistically with the Glucosamine HCl and Chondroitin Sulfate in these chews for hip and joint support plus Cod Liver Oil and B-Complex Vitamins support normal physical performance.
- Gut Health & Probiotics - These chews also contain a six-strain Gut Health Blend (500 million cfu per chew) and a Digestive Health Blend to promote gut flora while supporting normal bowel function for dogs.
- Heart, Liver & Immune Health - Multifunctional Bites feature powerful antioxidants, premium CoQ10, Cod Liver Oil and Vitamins A, C, & E to promote healthy cardiovascular function, support liver health and enhance immune response.
The study also found an association between approach speed and stripe frequency. A one-standard-deviation increase in approach speed—5.9 centimeters per second—was associated with a 0.50-hertz increase in stripe frequency (95% confidence interval: 0.31–0.72). In other words, faster approaches tended to coincide with more frequent stripe motion in the recorded sequences. This relationship is evidence that the display changes with the approach; it does not by itself show that faster stripes cause a particular outcome for the prey.
Numbers such as these help describe the behavior’s scale, but the central finding is the direction and function of the motion. The evidence does not establish one universal stripe speed or a precise distance at which every broadclub cuttlefish begins displaying.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
How does the passing-stripe display compare with the “leaf” display?
The researchers also compared filmed passing-stripe sequences with a “leaf” display, which uses a similar posture but lacks moving stripes. Their motion model found that the passing-stripe display generated nine times the motion strength of the leaf display. This is a model-based measure of visual motion, not a measurement of hunting success or survival.
The model also found that moving stripes produced a downward, directionally aligned motion signal, unlike the radial pattern expected from an expanding predator. That difference helps explain why the behavior might interfere with a looming cue: the display supplies a strong motion signal organized in a different direction from the cue that would normally indicate approach.
Also popular on Amazon
- SYMBIOTIC DIGESTIVE ECOSYSTEM: Our dog probiotics build a 4-way digestive ecosystem: Digestive enzymes pre-break nutrients for easy absorption, while probiotics + prebiotics balance and nourish gut flora. Pumpkin helps dogs with a sensitive stomach maintain regular bowel movements. These layers go beyond ordinary probiotics, turning every meal into steady nourishment, digestive ease, and enduring energy*—so your dog stays balanced and full of life.
- TRIPLE IMMUNE SUPPORT: Gut health drives immunity, and our probiotics for dogs target it. Probiotics help maintain a balanced gut microbiome and support mucosal immunity, while plant antioxidants* (Rosemary & Green Tea) and natural Vitamin E help protect immune cells from daily wear and tear. Formulated for triple immune support - helping your dog stay vibrant and ready for everyday adventures.
- DUAL-ACTION SKIN & COAT NOURISH: True skin and coat health starts from within. Gut and immune support work in sync with Salmon and Flaxseed Oils (Omega-3 & 6) to nourish skin and coat from the inside out. This dual-action care promotes a soft, shiny, and glossy coat you’ll love to touch.
- PURE INGREDIENTS: We believe in complete ingredient integrity. Every batch of our dog probiotic chews is crafted in GMP-certified facilities using trusted, premium sources. They are free from grains, soy, and artificial additives. This commitment to safety and quality ensures a clean formula you can trust for your dog’s overall wellness.
- TASTE DOGS LOVE: Made with natural duck flavor, our probiotic chews are loved by most dogs, even picky eaters. Unlike other hard chews, these soft, easy-to-bite chews are perfect for puppies and senior dogs. They help support digestive comfort, gut balance, and skin & immune health: areas commonly affected by occasional diarrhea, seasonal allergies, itchy skin, or paw licking. A tasty daily chew your dog will love.
Broadclub cuttlefish use other elaborate hunting displays, too. A University of Bristol release describes at least three other displays, and a separate 2025 paper’s abstract reports multiple displays during the approach phase. The available evidence here does not establish why a cuttlefish chooses one display over another, so the passing-stripe and leaf comparison should not be taken as a complete guide to the species’ display repertoire.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What does this research show—and what remains uncertain?
The strongest conclusion is that moving stripes can reduce shore crab responses to simulated approaching-predator stimuli in the laboratory, and that field observations and motion modeling support a plausible explanation for how the behavior works. The evidence brings together behavior in hunting sequences, a controlled stimulus comparison, and analysis of the resulting visual motion.
It is not proof that the display literally hypnotizes prey, that crabs never detect a cuttlefish using it, or that the cuttlefish’s success rate rises by a measured amount in the wild. The experiment tested shore crabs and visual stimuli, not every natural prey species and every condition in a hunt. The researchers also identify the possibility that prey may evolve counteradaptations to predators that use dynamic skin patterns.
That qualification does not make the finding unimportant. It clarifies what the study contributes: a supported mechanism for how a conspicuous moving pattern may make an approach less detectable, plus evidence that crabs respond differently to that pattern than to static or absent stripes. Whether this mechanism translates into a measurable advantage across wild encounters remains a separate question.
Also popular on Amazon
- COMPLETE 26-IN-1 DAILY WELLNESS FORMULA: Our advanced multivitamin for dogs is formulated to help support 26 vital nutritional areas as part of a daily routine. With essential vitamins A, C, D3, and E, these gummies help support the immune system and contribute to overall heart and brain health for dogs of all sizes.
- ADVANCED HIP AND JOINT MOBILITY SUPPORT: Formulated with Glucosamine HCl, Chondroitin, and MSM to help support cartilage health, joint flexibility, and everyday mobility — making them a great daily supplement for large breed dogs and active senior dogs.
- SKIN & COAT SUPPORT: Packed with Norwegian Salmon Oil and Biotin, our dog multivitamin helps nourish skin from within and supports a soft, glossy coat. Omega 3 fatty acids contribute to healthy skin and coat as part of a complete daily nutritional routine.
- PROBIOTICS & DIGESTIVE SUPPORT: Features a Six-Probiotic Blend (500 Million CFU) and Digestive Enzymes to help support gut health, smooth digestion, and nutrient absorption. Cranberry Powder is included as part of this comprehensive daily wellness formula.
- UNBEATABLE VALUE 250 COUNT JAR: Our 250-count jar provides lasting daily support in a delicious chicken flavor. Made in the USA in a GMP-certified facility, our soft chews are grain-free and suitable for puppies, adult, and senior dogs alike.
Why is the finding called motion camouflage?
Ordinary descriptions of camouflage often focus on whether an animal’s colors resemble its surroundings. Motion camouflage instead concerns how movement is perceived. A cuttlefish can remain visible yet potentially reduce the prey’s ability to read its motion as an approaching threat by producing a competing, directional motion signal.
In the broadclub cuttlefish study, that explanation links three observations: the display occurs during the close approach; downward-moving stripes can dominate the modeled motion signal; and laboratory crabs respond less often to expanding stimuli when those stimuli carry downward-moving stripes. Together, they support the proposed mechanism, while leaving open how frequently it works in natural encounters.
Quick wins for a faster PC:
Clear out junk files and repair common Windows errorsFree Scan →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Frequently Asked Questions
Can people see the broadclub cuttlefish’s stripes during a hunt?
Yes. The display is visually striking to human observers, but visibility to a person does not establish how a crab processes the pattern. The proposed effect depends on motion cues in the prey’s visual system, not on the cuttlefish disappearing from sight.
Does every cuttlefish use the same hunting display?
No single display is established as universal. Broadclub cuttlefish have been reported using several elaborate displays, and the evidence does not explain exactly how an individual selects among them.
Could crabs learn to recognize the moving-stripe display?
That remains an open question. The study’s authors note that the laboratory crabs may have been naïve to predators using dynamic skin patterns and call for further work on whether prey evolve counteradaptations.
What does 2.2 Hz mean for the cuttlefish’s stripes?
Hertz describes cycles per second, so the reported average of 2.2 Hz expresses the temporal frequency of stripe movement in the recorded sequences. It is a study average, not a prescribed rate for every hunt.
Leave a Reply