The white horse may catch our eyes, but the darker equines are the choice of the horsefly
The stunning coat of a white horse is prized by humans for its beauty and rarity, but in many cases the light color is disadvantageous for horses in the wild. White horses are more sensitive to solar radiation and are easily spotted by predators. However, a white coat gives horses the upper hoof when it comes to avoiding annoying, blood-sucking horseflies.
A female horsefly
Researchers in Europe monitored the frequency with which horseflies attacked white and brown horses and found brown horses were attacked by the pests nearly 4 times as often as white horses. The authors propose that this dark-coat preference is the result of the different light-reflecting properties of the horses’ coats. As shown by the lead author of this study in an earlier report, horseflies (and their relatives, known as tabanids) are attracted to horizontally polarized light. The light reflected off of white horses is less polarized than the light reflected off of dark horses, and thus attracts fewer pests.
See the original study: An unexpected advantage of whiteness in horses: the most horsefly-proof horse has a depolarizing white coat.
February 19, 2010 at 8:41 pm |
My best friend’s horse spends most of his life trying to be brown instead of white. Their soil stains him to a shade of pink/terra cotta. I find light colored horses may get picked on by other horses more because they stand out in a crowd when someone is angry.
February 20, 2010 at 1:24 am |
Interesting– another potential disadvantage to the white coat! Your friend’s “pink” horse reminds me of Cloud: Wild Stallion of the Rockies when he rolls in dirt and dyes himself pinky-orange! Thanks for reading, ~sly