SPRING WISRD MAGAZINE, VOL 6, ISSUE 2

colorblind. Yet they can change and match the color of their skin to their surroundings almost perfect ly. Scient ists are st ill stumped as to how they know what colors to match, but there are some theor ies. One hypothesis involves the animal's unique ?W?-shaped pupil. Unlike human eyes, the eyes of cut t lefish , and other cephalopods, contain just one kind of color-sensit ive protein restr ict ing them to only black and white vision. It?s theor ized that a cut t lefish can rapidly focus their eyes at different depths, taking advantage of a lensing property called ?chromat ic blur.?Color is perceived in wavelengths, and each color of light has a different wavelength that?s dist inguishable from another. The theory is that cut t lefish eye lenses bend some wavelengths more than others? one color of light shining through a lens can be in focus while another is st ill blurry? so by quickly switching back and forth between depths, a cut t lefish can figure out the color of an object based on when it blurs. In a study published in the Proceedingsof the National Academy of Sciences , scient ists built a computer model of an octopus eye and showed it could determine the object?s color just by changing focus, support ing the stated hypothesis. The second theory has to do with small cells in the skin of the cut t lefish called leucophores. Leucophores are flat tened, elongated, reflect ive cells found in the skin of some cut t lefish. The cells reflect white light? a combinat ion of all colors? appear ing br ighter and whiter while at the surface, closer to the sun, and then darker and more complex as the cut t lefish makes its way down the water

column. In order to change their color, cut t lefish rely on chromatophores, organs within their skin that contain pigment sacs which become more visible as small muscles pull the sac open, making the pigment expand under the skin. The muscles contract ing the pigment sacs are closely linked to electr ical act ivity in the chromatophore nerve. An electr ical impulse causes the radial muscle fibers to pull outward which expands the middle of the pigment sac. An ear ly exper iment done by Ernst Florey in 1969 showed that the increase in frequency of the electr ical nerve act ivity widened the radial muscle, which in turn expanded the pigment sac. Florey believed the radial muscle to have elast ic propert ies which allowed the pigment sac to contract after being opened. Chromatophores are able to open and close quickly because they are neurally controlled. Neural control of the chromatophores allows for cut t lefish to change their appearance almost instant ly, enabling them to generate small pat terns or details on their skin for camouflage. Chromatophores are used to match the br ightness of the background and to produce components that help the animal achieve general resemblance to the substrate or break up the body's out line. Another researcher named Roger Hanlon, theor ized that cut t lefish have three basic camouflage pat terns or ?templates?that the animal cycles through. ?In the laboratory we can test each of these pat tern types and the animal?s magic is looking at a complex visual scene and only picking out one or two visual cues to turn on the r ight camouflage pat tern type,?

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