What makes animal's eyes reflect, and why do they reflect in different colors??
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The red-eye effect in photography is the common appearance of red eyes on photographs taken with a photographic flash. The light of the flash occurs too fast for the iris of the eye to close the pupil. The flash light is focused by the lens of the eye onto the blood-rich retina at the back of the eye and the image of the illuminated retina is again focused by the lens of the eye back to the camera resulting in a red appearance of the eye on the photo. (This principle is used in the ophthalmoscope, a device designed to examine the retina.)\n\nIn many species or animals, a light-reflecting layer behind the retina that improves night vision, intensifies this effect. This leads to variations in the colour of the reflected light from species to species. Cats, for example, display blue, yellow, pink, or green eyes in flash photographs.  Dogs' eyes will usually flash green in photographs.
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Why is there no mammal with green fur? Green is a good camouflage color, and nonmammals (for example, frogs, snakes, and birds) do come in green. Why not mammals?\n\nThis is similar to the first question I asked on yahoo! answers, and this was the link from the best answer to that question. It was exactly what I was looking for, hope you think so too.\n\n\nI know from my general zoology classes that mammals can make only two kinds of pigment: melanin (black or brown pigment) and the reddish-yellow pigment that red-haired people have. So my first idea for a simple explanation of the nonexistence of green mammals was to say that mammals just can't make green pigment for some reason. This is of course not a good evolutionary explanation, but at least it superficially answers the question.\n\nAs I started researching this a bit more, I was astounded to discover that frogs, birds, and others in the tetrapod, or four-legged, world can't make green pigment, either! Or blue, for that matter. It turns out that all color variation that we see in tetrapod animals is the result of different combinations of patterns of deposition and refraction of the same two types of pigments: black and yellow-red. A chameleon's color changes because of rapid shape changes in refractory cells in its skin, not by rapid production or release of an actual pigment. Frogs are green because of the pattern of refraction of blue light by special cells in their skin, which blends with their yellow pigment.\n\nThe colors of bird feathers are also generated by light refraction but by a different mechanism. The surface of feathers has microscopic ridges that form ordered tracks, much like the surface of a CD. The spacing of the ridges and the size and orientation of the pigment granules they contain determine the feathers' brilliant greens and blues (see links in reference 2). Tiny air pockets in feathers can add to color variation in birds. Light refraction is also responsible for the color of the human iris, which can range into deep blue or green hues. Another example is the sky-blue nose of the mandrill. For an exploration of the ways animals make different colors, see reference 1.\n\nAs you can see, the question is really why mammals don't have the ability to generate a variety of colors in their fur. This is a difficult question, and until we master time travel—to be able to trace back the evolution of mammals—we won't know the answer with certainty. But it's interesting to speculate, so here are some possible explanations.\n\n1. I think that the most important difference is in the lifestyle of mammals. Being warm-blooded animals, they are constantly in search of food and are moving a lot. Even if an animal has the best camouflage, as soon as it starts moving, it is more easily detected. In contrast, many amphibians and reptiles can spend a long time being motionless, and here looking the same as a leaf nearby helps more. I believe that during evolution, mammals have "invested" more into working out active escape mechanisms (for example, running away and hiding in burrows) rather than into developing passive camouflage techniques.\n\n2. Scientists believe that the first mammals were relatively small, ratlike creatures that ate insects. Their habitats were probably different in terms of background color patterns compared with the habitats of amphibians and reptiles. Mammals, of course, originated on land, while amphibians never leave the source of water. More green is around amphibians, and therefore we find more green amphibians.\n\nIn contrast to their early ancestors, many mammals are now large, and for them, a factor of size comes into play in determining coloration. As we know from classical statues, it's difficult to cover a whole mammal with a fig leaf (but it is quite possible for a frog). A solid-green mammal would in fact stand out in real habitats rather than be hidden. For a large animal, being dappled h
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You are on the right track. It's quite simple:\n\nGenerally, wet things look darker because they refract less light. Light, which is made of photons, refracts against an object and lands on your retina and your brain can register some amount of darkness or brightness. Now when that object is wet (assuming it is hydrophilic or "wettable") more light is absorbed by the water so less light lands in your eyes and the object appears darker.\n\nGreat question!
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The most obvious answer is that it reflects the sky since you can see reflections of clouds also. But reflection is only part of the answer. \n\nIt is true that part of the light you see is a surface reflection of sky light. The amount of this sort of reflection, though, depends on a number of things such as your viewing angle. On the other hand, much of the color you see comes from the water's depths. \n\nWhite sunlight contains all colors. Water absorbs some of these colors more than others. But you need a lot of water to notice this effect - which is why water cupped in your hand has no color at all. In a large body of water though, the water molecules quickly absorb red light, but they don't absorb blue light nearly as well. So in this case, more blue light is transmitted through the water. It's actually the same principle behind why the sky is blue. \n\nThe blue effect is often increased because ocean and lake water usually contains floating particles of dirt, and dead and living plants and animals. They help reflect the blue light back upward - so that the lake or ocean looks blue. The blue-green of tropical waters is due entirely to absorption of red light rather then suspension of particles. It's a different blue than the blue of the oceans off the northeast coast, whose blue is caused by suspended particles and plants. \n\nSo now we know why some bodies of water appear blue, but what about the other water colors, like gray, brown and black? Different colors can be produced by specific things suspended in the water. Mud acts in the opposite way from water -- it reflects red light more than blue. So muddy water looks brown. Since rivers are big transporters of mud, they usually appear brown. Peat dissolved in water absorbs almost all the light that touches it - so a lake full of peat may look black. The ocean often usually looks gray on a stormy day. Partly, that's reflected gray sky - but it's also because clouds filter out a lot of the sun's red light before it ever reaches the water. \n\nColors of water can be pretty distinctive. The Black Sea is so named because of its color, a very dark almost black color. In this case, it's the almost constant fog over the Black Sea that absorbs incoming light and makes the sea appear black. It was enough to make the Turks and many other sailors want to avoid what they saw as an evil looking sea!
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Perceived colour is dependent on the light wavelengths being reflected back to your eyes. What's reflected changes according to depth, substrate (if it's shallow enough to see the substrate) turbidity (as in mud and organic junk and whatever else affecting the clarity of the water), biological content (i.e. high levels of phytoplankton can make water appear very green, and shallow tropical areas with very little plankton can appear bright blue, etc).
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Here's an idea: have your object be a mirror, or at least something reflective.  Animals always think they see another animal in a mirror.  Cats will react by arching, puffing their tails, meowing, and even charging the mirror.
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Hair color, eye color, and also skin color are determined by special proteins called pigments.  The pigments in your hair, eyes, and skin are encoded in your genes, which is was these traits are said to be genetic.  All molecules absorb some wavelengths of light and reflect others.  Pigments are typically complex molecules that reflect certain wavelengths in the visible spectrum and absorb others.  Different people have different color pigments because there are minor changes in the DNA sequences that code for the pigments which result in minor changes in the molecules themselves, which in turn change the wavelenghts of light that are reflected and absorbed.  If someone has blue eyes, it is because the pigments in their eyes reflect a lot of wavelenghts of blue light, and absorb most other colors.
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Birds and reptiles have better color vision than humans\nMost mammals have poor color vision by human standards.\nPrimates have vision like humans.\n\nColor vision arises from photoreceptor cells in the eye called cones. \n\nBirds and reptiles have four different kinds that are sensitive to four different wavelength ranges. Most mammals have only two types having lost half somewhere in the distant past due to mutations. Most of the mammals that lived in the shadow of the dinosaurs were nocturnal, so color vision wasn't very useful to them anyway.\n\nPrimates have the same two kinds of cones that mammals, birds and reptiles have in common, but unlike other mammals they have a third type which is unique to primates, it arose via a mutation and allows human style color vision. It's sort of an awkward compromise when compared with birds and reptiles though. They can see UV light, we cant'\n\nI'd add that any nocturnal animal regardless is less likely to have good color vision, because overall light intensity is sensed by a different kind of photoreceptor cell (rods) and good night vision requires more rods than cones. You can't have your cake and eat it too.\n\nI don't know much about fish and amphibians. \n\nSome insects have very good color vision in tems of color perception. Any of the ones that co-evolved with flowering plants would see color better than usb ecause of that extended spectrum thing. Although the specifics of their vision systems aren't familiar to me.\n\nI only know the stuff on bird, mammal and primate vision because of an article in a recent issue of Scientific American.
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From a physics/physiology standpoint, we have color because light waves come in different lengths and our eyes perceive a limited band of thoses lengths with differing responses by light sensors in the eyes.\n\nFrom an evolutionary standpoint, color vision (as opposed to black and white), gives us a great deal more information to process our environment.  For instance, a brightly colored bird might hardly be visible to an animal with only black and white vision, but we see it easily, even against a confusing background.  Color can help us see the difference between animal (browns) and plants (greens), healthy(a child covered in mud) and unhealthy (a child covered in blood), and other differences that are more easily recognized due to the greater information richness available.
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There's a peak absorbance of rods and cones in the retina.  Humans have three peaks which represent the primary colors (for light) red, green, and blue.  The colors we see are our brain's interpretation of input on those three colors plus general light level input from rods.  Based on the numbers of rods and cones and the absorbance spectra of the different cones, researches can get an idea of the color vision of different animals.\n\nMost mammals are dichromatic (two colors).  Note how non-colorful they tend to be.  Certain primates are trichromatic (three colors).  Birds, reptiles, amphibians, and insects are also trichromatic or more.  Note how colorful they tend to be.
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dog, cats, and some other animals have what is called a tapedum lucidum, it is a part of the eye that reflects all available light...this is why animals can see better in the dark than humans, as we don't have one.\n\nsorry redtail...the tympanic membrane is in the ear...you must have meant tapedum lucidum, right?
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Chickens, being primarily diurnal (day living) birds (a group that tends to have good vision and colour acuity) probably have at least some ability to distinguish colour.\n\nThe usually drab markings of most chickens (especially wild Galliformes like grouse) are probably more for camoflage than due to an inability to see colour.  There are some Galliform avians that definitely have bright plumage for mate attraction, indicating that colour vision is present in those species (most notably Pavo cristatus - the Peacock), so it's likely that chickens can too.
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No. But that does NOT mean bulls are colorblind. Many mammals cannot tell the difference between red and green, but do see more than black and white.\n\nMammals in general have poorer color vision than birds and reptiles. This is believed to be because they were nocturnal scavengers early on in evolution and eventually lost 2 of the 4 types of cells in the eye that allow us to see color. These are known as cone cells.\n\nSome primates, such as humans, have regained a 3rd type of cone cell. Thus allowing them to tell the difference between red and green. Being that this is an evolutionary new cone, it is no surprise that this newer color distinction is more commonly lost than the older blue and yellow.
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Chances are they have a visiual cue to the colour of the berries. Its really a co-evolutionary thing. The tree wants to spread its seeds so it signals to the bird with bright red berries for example....come and eat me. Also many birds have very acute vision.....think of vultures flying high above the plains scanning for carrion. Animal senses can be very different from ours.\nCheers.
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Animals that see at night have several adaptations; these can include some or all of the following:\n- Relatively larger eyes (example: owls)\n- High density of rods (light-detecting sensory cells). Rods have a pigment called rhodopsin that is especially sensitive to light even at low levels (in these animals, the concentration levels of rhodopsin are also higher).\n- Possession of a tapetum lucidum (this is Latin for "bright or clear carpet"). This is a highly reflectant layer that is situated behind the retina, it collects all the light including the faintest wavelengths and redirects it to the retina, enhancing vision.\n\nSee a diagram here:\nhttp://www.natureshift.org/rangerR/forest/images/eye-dia.jpg\n\nThis reflecting layer is what causes the eyes light up when they are illuminated by strong focused light. The color of the eye shine depends on the structure of the tapetum lucidum and also on the pigmentation of the animal. \nSee more about these structures in the following Q&A:\nhttp://answers.yahoo.com/question/;_ylt=AuiC1gBR8wcII9_SKbjYh4MjzKIX?qid=1006033114457\n\nThis high sensitivity to light is also reflected in the shape of the iris. Nocturnal animals often have vertical pupils that are able to narrow to mere slits during the day, to protect the extremely sensitive mechanism from the intense daylight.
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(1)mirrors reflect light because it has a shiny and reflective metal behind it.\n(2)camera lenses
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Oddly enough there are only two pigments in birds and amphibians two, exactly the same two pigments. Yet we see birds and frogs in every colour of the rainbow. So we really shouldn’t be surprised to see a few bright mammals.\n \nThe way that animals usually generate blue and green colours is by utilising fibres arranged in rows or grids to refract light. That allows the skin to scatter the short blue and green wavelengths back to the observer while absorbing the longer reds. In the case of the mandrill the skin contains rows of collagen fibres designed to achieve exactly that purpose.\n\nThe only other blue mammal I know of is the vervet monkey, which has bright blue testicles. You can see a picture of one in the link below.