| Camouflage Strategies | |
| Break Outline | Many predators use prey outlines to notice and attack prey. Color change can allow cephalopods to blur the outline of their body to help avoid this manner of prey detection. Destroying the outline of the animal is also an important part of becoming part of the surroundings. The alternate method to destroy an outline is disruptive patterning. This can take the form of bold stripes and block patterns. This is sometimes not very effective against human eyes, but against predators that rely heavily on outline recognition this is an effective strategy (Allen et al 2009). |
An octopus hiding. It is difficult to see where the animal stops and the background begins. |
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| Become part of surroundings | The ability of cephalopods to match backgrounds has been long known, but puzzling in light of the discovery that cephalopods are color blind. Interestingly, cephalopods seem to be able to recognize the spectral reflectance of surfaces. Cephalopods closely match the spectral reflectance of the surfaces they sit on. Since detection of spectral reflectance is not based on color vision, cephalopods could use this method of seeing patterns both in communication and camouflage. Becoming part of the background is more effective because of this matching; predators that might not be fooled by a simple color match can be fooled by this more sophisticated mimicry (Mathger et al, 2008). |
A cuttlefish mimicking gravel. This mottled appearance is a common camouflage tactic for cuttlefish. |
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| Become an object in the surroundings | This method is similar to becoming part of the background with regard to hiding and spectral reflectance except that the cephalopod is either a stationary object like a rock or coconut etc., or something more exotic like a ray or lionfish. These more elaborate forms of mimicry are usually practiced by the mimic octopus or related species (Allen et al 2009). |
An octopus posing as a rock. |
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| Countershading | Countershading is a very basic marine camouflage method. It consists of having a dark dorsal side and a light ventral side. This helps to hide the animal in the light when viewed from below and from standing out against the dark when viewed from above. Cuttlefish and squids use this method of camouflage frequently, but unlike fish or other countershaded marine animals, cephalopod countershading is dynamic. When disoriented, fish can become visible when their orientation changes. This is not a problem for cephalopods because they are able to shift the dark and light areas of their bodies to account for any movement. This phenomenon is readily observed in even anesthetized animals. This ability takes advantage of the statocysts (orientation sensing organ). When the statocysts in a cuttlefish are destroyed, the countershading is stuck on the default dark top, light bottom (Ferguson et al 1991). |
The countershading reflex. The upward side stays dark and the bottom stays light. |
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