underwater camouflage underwater camouflage set methods achieving avoidance observation allows visible aquatic organisms remain unnoticed organisms predators prey camouflage large bodies water differs markedly camouflage land environment essentially sides light falls generally variable background compare trees bushes main camouflage methods water transparency reflection counter illumination transparency important metres ocean counter illumination main method metres metres camouflage important dark waters metres camouflage relatively shallow waters like terrestrial camouflage additional methods animals example self decoration employed crabs animals sea dragon fish including sharks distraction fish active camouflage ability change colour rapidly fish cephalopods including octopus squid context ability camouflage oneself provides survival advantage constant struggle predators prey natural selection produced wide variety methods survival oceans aristotle commented color changing abilities camouflage signalling cephalopods including octopus octopus seeks prey changing colour render like colour stones adjacent alarmed methods main camouflage methods oceans transparency reflection transparency important metres ocean main method metres metres camouflage important dark waters metres animals open sea use methods camouflage camouflage relatively shallow waters like terrestrial camouflage additional methods animals different groups methods camouflage described turn transparency transparency common dominant animals open sea especially live relatively shallow waters found species larger animals floating marine animals float near surface highly transparent giving perfect camouflage transparency difficult bodies materials different marine animals gelatinous bodies composed mainly water thick highly transparent makes makes large muscle mass swim fast gelatinous animals cent transparent transparency cent animal invisible predator depth metres better transparency required shallower water light brighter predators better example prey cent transparent optimal lighting shallow water transparency effective deeper waters tissues muscles transparent provided thin organised regular layers small compared visible light familiar examples transparent body parts lens eye lens protein protein structures transparent notably equivalent light absorbing structures eyes absorb light able function camera type eye cephalopods completely finally structures visible reason lure prey example cells transparent resemble small examples transparent marine animals include wide variety larvae including floating worms crustaceans fish adults resembling shores live adult mainly transparent like background small amazon river fish associates transparent invisible species appear select transparent conventionally patterned according local background environment reflection fish covered highly reflective scales giving appearance mirror glass reflection widespread dominant fish open sea especially live metres transparency achieved imitated effectively animal body highly reflective medium depths sea light comes mirror oriented vertically makes animals fish invisible fish upper ocean herring marine extremely flattened leaving body millimetres thick body resemble aluminium foil mirrors consist microscopic structures similar provide structural coloration crystals spaced apart interfere achieve nearly cent reflection deep waters lives blue light needs reflected mirrors apart provide good camouflage fish herring live shallower water mirrors reflect mixture fish accordingly crystal range different fish bodies rounded cross section mirrors ineffective laid flat skin fail reflect horizontally overall mirror effect achieved small oriented vertically found marine animals fish cephalopods including squid octopus multi layer mirrors protein counter illumination counter illumination underside ventral region body found species live open ocean metres generated light increases animal seen match ocean surface effective form active camouflage notably species squid squid light producing organs scattered creating sparkling glow prevents animal appearing dark shape seen counter illumination camouflage likely function marine organisms light produced attract detect prey signalling common fish including sharks animals groups turtles animals dark upper sides match ocean depths light avoid appearing dark bright sea surface practised animals sea dragon leaf resemble parts plants gently rock bodies current fish species dragon striking difference appearance adults juveniles juvenile resembles loose piece sea vertical position head pointing downwards way perfectly resembles movement piece moving forth surge self decoration self decoration employed animals different groups including crabs attach materials environment living organisms camouflage example japanese crab growing shell lives crab orange bitter eaten fish similarly sea use tube feet pick debris attach upper surfaces use shells rocks algae sea distraction fish near tails distract attacks away vulnerable head eye example conceal eye large near tail giving impression head tail end body disruption outlines fish bold patterns sides breaking outlines strong contrasts fish like similar bands colour extend fins projecting far body distracting attention true shape fish fish mimic elaborate projections spines combined complex coloration effect destroying signature fish outline animals helping appear pieces algae coloration variety marine animals possess active camouflage ability change colour rapidly living fish hide effectively variety backgrounds cephalopods including octopus squid similarly use colour change case camouflage signalling example big blue octopus octopus hunts day match colours textures surroundings avoid predators enable approach prey perfectly resemble rock coral hiding necessary order scare away potential predator display markings resemble eyes like excellent camouflage use cryptic coloration avoid detected prey predators possible swim crawl fins constantly changing colours patterns match background study demonstrated ability change pattern seconds able match pattern placed changing pattern extremely complex process involving vision fish eyes damaged covered sand difficulties matching pattern surroundings fish hunting hiding predators sand leaving eyes protruding
Underwater camouflage