colors+and+the+eye,+yea+boi!!!!!

In the human eye, light enters the pupil and is focused on the retina by the lens. Light-sensitive nerve cells called rods(for brightness) and cones (for color) react to the light. They interact with each other and send messages to the brain that indicate brightness, color, and contour.

Some animals are color blind... Just some can see some certain colors, like a horse can see blue's and greens, deer can see yellows and greens..etc... Dogs most definately are not color blind. There are some differences in their vison from that of humans, but -- contrary to popular myth, their eyes contain both rods (cells that detect light and movement but not color) and cones (which detect color and need more light than rods do in order to activate). Rods are groups of light sensors connected to one neuron. Cones, on the other hand, are one neuron per cone and, unlike rods, have a narrow range of wavelengths they'll respond to. Dogs' cones respond to, what in the human range of vision, would be yellow, and blue-indigo. Most breeds of dogs also do not resolve images well at distance, with a focal range of about 20/70 (to a human's healthy vision of 20/20). This means, what you see at 75' is about what a dog sees at 20' (exceptions are Labrador Retrievers, who approach 20/20 -- which is why they're often used as guide dogs). Dogs also have a wider angle of acceptance -- around 270 degrees (as opposed to a human's 180 degrees). This means they are more aware of events on the periphery of human sight of course, but as the acceptance angles of vision of the two eyes don't intersect as completely as humans, they don't get really good distance ranging except for a small angle of acceptance directly in front of them. You can pretty easily test this if your dog likes retrieving. Get a bunch of identical balls in different colors, and watch for the surprisingly different reactions. Source: Turtles, Tortoises and Terrapins: Survivors in Armor by Ronald Orenstein. Turtles aren't colorblind. At least some turtles can see in the red-orange-yellow part of the spectrum...box turtles (for example) like to eat berries, and the color vision can help them spot the ripening fruit. Birds are not color blind because you can teach a parrot to recognize colors. This is also true in a peacock's colorful wings. Good point! While dogs have only two types of cones (see above about cones and rods) that detect yellow and blue-indigo, and humans have 3 (Cyan, Magenta, Green or Red/Yellow/Blue), birds have four, with the ability to see into the ultraviolet as well. More Pure white, shorthaired cats with two blue eyes are often deaf (not blind!) Pure white, persian longhaired cats, are color blind. One in four human males has a form of colorblindness, with differing levels of severity, or acuteness. Deer are color blind. This is why hunters where blaze orange. It stands out for the hunters, but isn't noticeable for the hunted.