The cuttlefish changes its stripes continuously, giving a flowing sensation. Scientists confirm that this flow of stripes is a strategy for camouflage during hunting./Courtesy of the U.S. Monterey Bay Aquarium

The giant cuttlefish (scientific name Sepia latimanus) has stripes that continuously change, giving the impression of flowing. Scientists have confirmed that this flow of stripes is a camouflage strategy during hunting.

A research team led by Matteo Santon, a professor in the Department of Life Sciences at the University of Bristol, announced on the 27th the results of a study that experimentally verified what effect the 'passing-stripe' camouflage used by giant cuttlefish during hunting actually has. This study was published in the international journal Science Advances.

The giant cuttlefish is a master of camouflage. It changes its skin color and texture to resemble surrounding rocks or seaweed to hide. According to research from the team, the giant cuttlefish employs four unique behaviors to confuse its prey during hunting. Notably, these include the flowing stripes, swaying its body from side to side, spreading its arms like coral, and maintaining stripes without movement.

The giant cuttlefish adjusts its skin chromatophores to create black stripes, sequentially changing the position of the stripes over time, creating the illusion of flowing downward. The research team confirmed how this camouflage affects hunting.

The giant cuttlefish captures and approaches its prey./Courtesy of Matteo Santon

First, the researchers fixed a crab, the prey, in a treadmill-like device in the laboratory's tank and showed videos of the giant cuttlefish approaching. They presented three scenarios: no stripes, stripes at rest, and stripes flowing downward.

The crab showed the least response to the giant cuttlefish with stripes flowing downward. This means that when the giant cuttlefish uses the flowing stripe camouflage, the crab feels less threatened.

The researchers also analyzed, through simulations of the crab's visual system, what visual impressions the stripes give from the prey's perspective. Generally, as predators approach, crabs detect increasingly larger movements, feeling threatened and fleeing. However, when the giant cuttlefish flows its stripes downward, the sense of approaching is less noticeable, leading to reduced fleeing behavior.

In subsequent field experiments, the researchers used high-speed cameras to capture wild giant cuttlefish from various angles, analyzing hunting distance, speed, and the timing of stripe usage. The giant cuttlefish rapidly approached at the start of the hunt but slowed down about 1 meter away, beginning the behavior of flowing stripes. The speed at which the stripes flowed varied with the giant cuttlefish's approach speed, illustrating that this camouflage is not simply a reflexive action but a strategy that is actively adjusted according to the situation.

The hunting appearance of the giant cuttlefish seen from the perspective of the prey./Courtesy of Matteo Santon

The research team evaluated that this study is the first case of confirming 'movement camouflage' in nature, which allows one to hide while moving without being detected. They added that while other cephalopods also display various skin patterns in predator-prey interactions, it has not been clarified whether this actually operates as a strategy to conceal movement.

References

Science Advances (2025), DOI: https://doi.org/10.1126/sciadv.adr3686

Ecology (2025), DOI: https://doi.org/10.1002/ecy.70021