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Re: [RC] Purple Flowers - Diane TrefethenColor blindness can be very subjective. From the point of view of the individual "afflicted", they don't perceive themselves as color blind. In the human species, most color blind people are male and the "defect" is passed to sons by their mothers. My mother-in-law was not color blind but her son, my husband, could not differentiate green from blue. His daughters are not color blind but one of them has a son who can not tell green from blue. Thomas was doing just fine, blissfully unaware that "green" and "blue" weren't different words for the same color. He called grass "green" because that's what everyone else called it, not because he could see that it was "green" and not "blue".So, are horses color blind? Well, from their perspective, no. The world looks the way it looks and if to a horse, everything is really shades of gray, so what? The horse can see things as well as he needs to. Then to add another layer of confusion, not all "colors" are in the human visible spectrum. Light is electromagnetic radiation. Humans see a very narrow range of the EMR spectrum. The lowest we see is red, the highest is purple, or violet. Trichromatic insects, such as honeybees, have three types of pigment receptors, like we humans do. However, their three pigment receptors do not coincide with ours. The spectrum of colors visible to insects is a little higher in frequency than what we humans can see. So, while violet light is the highest frequency of color humans can detect on the electromagnetic spectrum, many insects can see a higher frequency of light invisible to us, ultraviolet light. Though we don't know (because we can't see) the "colors" of the ultraviolet, with modern frequency attenuating and filtration techniques, we can interpret them visibly and suddenly the world looks very different. Flower petals are decorated with intricate patterns highlighting their reproductive areas and the adjacent sources of nectar for visiting insects. Even the most apparently drab butterflies display hugely sophisticated patterns. Might it be that horses share this talent? That they too can see into the ultraviolet? Perhaps flowers that appear to us as plain purple are really reflecting oscillating patterns of ultraviolet light so that insects see a bright, wavering neon sign that says, "FOOD HERE" while horses simply see a fluctuating series of waves that are disquieting, and if we could see them, even nauseating. To a horse, that carpet of purple might look like an undulating ocean of flickering and flashing light. If so, it's no wonder that they'd want to steer clear of those pretty, purple flowers. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Ridecamp is a service of Endurance Net, http://www.endurance.net. Information, Policy, Disclaimer: http://www.endurance.net/Ridecamp Subscribe/Unsubscribe http://www.endurance.net/ridecamp/logon.asp Ride Long and Ride Safe!! =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
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