I have been re-reading an article based on some research done at UGA in 1992 on deer vision. (I assume most hunters have read about it ). Does anyone know if we can generalise and say......."Mammals with good night vision have poor color vision"???????

Bones

Most mammals have only 2 types of color receptors and see only the blue/green (including some of the longer wavelength ultraviolet) and yellows well and so do not as readily detect the red and blaze orange. An exception is the primates, including humans, which have 3 types detectors and see the full color spectrum as we (except color blind individuals) do. Birds have 4 types of detectors and presumably have a much richer color perception than we do.

The color receptors are less effective in low light which is why we tend to see things more as dark and light under very low light conditions. Good night vision is related to a higher number of rods (as contrasted to the cones that provide color vision) in the retina, larger eyes, and the presence of a reflective layer within the eye that permits more effective use of the light that enters the eye. So the ability to see in low light appears to be independent of the ability to distinguish among colors during the day.

Hey Bones, check out the this thread, as I had a similar question, more related to colors, but still relevant.

http://www.shootersforum.com/showthread.htm?t=24514&highlight=Color

There's some links and some good read in there.

Most mammals have only 2 types of color receptors and see only the blue/green (including some of the longer wavelength ultraviolet) and yellows well and so do not as readily detect the red and blaze orange. An exception is the primates, including humans, which have 3 types detectors and see the full color spectrum as we (except color blind individuals) do. Birds have 4 types of detectors and presumably have a much richer color perception than we do.

The color receptors are less effective in low light which is why we tend to see things more as dark and light under very low light conditions. Good night vision is related to a higher number of rods (as contrasted to the cones that provide color vision) in the retina, larger eyes, and the presence of a reflective layer within the eye that permits more effective use of the light that enters the eye. So the ability to see in low light appears to be independent of the ability to distinguish among colors during the day.

What is the third receptor, I thought we only had cones and rods. It's a combination of the two that allow a broad color sensitivity. Intensity plays a major role in color perception. In bright, moderate, and low light there is sufficient energy to sustain normal photopic vision and we see all the colors. In very low light conditions the human visual system shifts its peak visual acuity (photopic vision) from 555 nano meters (bright lime green) to around 450 nanometers called scotopic vision (blue). In this condition, the rods, less long wavelength (red) color perceptive, are the dominant receptors. Humans are more restricted in night vision (very low light conditions) by lens size and shape than wavelength sensitivity. Our eyes simply aren't that efficient at gathering light and the receptors have a relatively small dynamic range.

Emergency vehicles have been playing off the optimum viewing conditions for years. Fire engines and ambulances have gone from red to lime green because under normal lighting conditions you can see that color from a much greater distance. The same is true with lime green golf balls. Cop cars sport one red and one blue light on top because the red is more visible during the day and the blue is more visible at night. Next time you are out at night driving away from flashing lights look in your mirror. You will be surprised how quickly you loose the red but you will see the blue from an extremely long distance.

Sitting in the woods from dark to light in the very early hours of the morning you won't see much, if any, color contrast. Everything will appear black and white (just shades of grey) then boom, green is the first and only color you will see for several seconds until it gets sufficiently light to support full color vision.

What is the third receptor, I thought we only had cones and rods. It's a combination of the two that allow a broad color sensitivity. Intensity plays a major role in color perception. In bright, moderate, and low light there is sufficient energy to sustain normal photopic vision and we see all the colors. In very low light conditions the human visual system shifts its peak visual acuity (photopic vision) from 555 nano meters (bright lime green) to around 450 nanometers called scotopic vision (blue). In this condition, the rods, less long wavelength (red) color perceptive, are the dominant receptors. Humans are more restricted in night vision (very low light conditions) by lens size and shape than wavelength sensitivity. Our eyes simply aren't that efficient at gathering light and the receptors have a relatively small dynamic range.

Emergency vehicles have been playing off the optimum viewing conditions for years. Fire engines and ambulances have gone from red to lime green because under normal lighting conditions you can see that color from a much greater distance. The same is true with lime green golf balls. Cop cars sport one red and one blue light on top because the red is more visible during the day and the blue is more visible at night. Next time you are out at night driving away from flashing lights look in your mirror. You will be surprised how quickly you loose the red but you will see the blue from an extremely long distance.

Sitting in the woods from dark to light in the very early hours of the morning you won't see much, if any, color contrast. Everything will appear black and white (just shades of grey) then boom, green is the first and only color you will see for several seconds until it gets sufficiently light to support full color vision.

I should not have said 3 receptors. The rods are receptors for non-color specific light - black and white. The cones are the receptors for color, but the light wave frequencies for which the cones are most sensitive are concentrated at 2 frequencies for most mammals, 3 frequencies for primates, and 4 frequencies for birds. There was an excellent article on this in a recent issue of either "Discovery" or "Scientific American".

The studies on colors most effective for safety are based on human color perception, but the color perception of non-primate mammals is different. The color perception in non-primate mammals is based on only 2 primary frequency ranges while human color perception is based on 3.

The color perception in non-primate mammals is based on only 2 primary frequency ranges while human color perception is based on 3.

Thanks Guys. I think this answers my Question

Bones