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Underwater camouflage is the set of methods of achieving crypsis—avoidance of observation—that allows otherwise visible aquatic organisms to remain unnoticed by other organisms such as predators or prey. Camouflage in large bodies of water differs markedly from camouflage on land, as the environment is homogeneous, with light always falling from above, while there is generally no variable background as with terrestrial foliage. Three main camouflage methods predominate in water: transparency, reflection, and counterillumination. Transparency and reflectivity are most important in the top 100 metres of the ocean; counterillumination is the main method from 100 metres down to 1000 metres; while camouflage becomes less important in the dark waters below 1000 metres. Camouflage in relatively shallow waters is more like terrestrial camouflage, where additional methods are used by many animals. For example, self-decoration is employed by decorator crabs; mimesis by animals such as the leafy sea dragon; countershading by many fish including sharks; distraction with eyespots by many fish; active camouflage through ability to change colour rapidly in fish such as the flounder, and cephalopods including octopus, cuttlefish, and squid. == Context == (詳細はpredators and prey. Natural selection has produced a wide variety of methods of survival in the oceans.〔(【引用サイトリンク】author=Sewell, Aaron )〕 In ancient Greece, Aristotle commented on the color-changing abilities, both for camouflage and for signalling, of cephalopods including the octopus, in his Historia animalium:〔Aristotle. ''Historia Animalium''. IX, 622a: 2-10. About 400 BC. Cited in Luciana Borrelli, Francesca Gherardi, Graziano Fiorito. ''A catalogue of body patterning in Cephalopoda''. Firenze University Press, 2006. (Abstract ) (Google books )〕 :The octopus ... seeks its prey by so changing its colour as to render it like the colour of the stones adjacent to it; it does so also when alarmed. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Underwater camouflage」の詳細全文を読む スポンサード リンク
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