Zebras Have Their Own Bug Repellent?
Eww bugs! They are so annoying! We humans are lucky that we can apply repellents to avoid nasty bites. But what's an animal to do? They have no choice but to spend their days shooing them off with their tails, unless of course they are zebras, who apparently have an automatic repellent - Their striped skin!
Scientists had originally thought that the reason the animal had developed the black and white lines was to help protect itself from predators in the African Savannah, because the stripes make it difficult to single out one zebra that is traveling with a herd. While that may be true, the theory has never really been tested or proven. Now, the experts have another - that the stripes evolved to repel the pesky horse flies that not only feed off their blood, but also, transmit dangerous germs into the bodies of these innocent animals.
The study was performed by a team of Swedish scientists led by University of Lund's evolutionary ecologist, Susanne Akesson. One of the clues that got them thinking along these lines was the fact that darker horses get bitten more often than light colored or white ones.
Given that zebras are born black and only develop stripes as they grow older, made them theorize that the stripes may be something the animals developed to make themselves less attractive to flies.
To test if this may indeed be the case, they painted some boards at a horse-fly infested horse farm in Budapest with patterns of black and white stripes of varying widths and pasted a layer of glue on it. What they noticed is that the places the black and white stripes were at their narrowest (similar to what zebras have), attracted the least amount of flies. They achieved similar results when they painted horses with black and white zebra-like stripes.
While the researchers are not sure why this may be the case they believe it may be something to do with the way insects operate - Many, are drawn to horizontally polarized light - the glare that you encounter when you look at a horizontally shiny surface like water, snow or sand. To horseflies, this is the sign of water, a place where they mate and lay eggs. The stripes on the zebra not only reflect different polarizations from the two colors, but are also, vertical, which the scientists believe helps deflect horseflies that are in search of a cool flat place to land.
While this theory does make logical sense, nobody is 100% sure that it is really true, given that it has never been tested on a real zebra. If it is true, it does raise the question of why the horse, a close relatives of the zebra failed to develop stripes. The researchers believe that this could be because there are more horseflies and horsefly species in Africa, where zebras reside, than anywhere else in the world.
Additional experiments will probably be needed to confirm if the Swedish scientists are right, but I get the feeling that the only way we will know for sure why zebras got their stripes is if they tell us - A miracle, we can only hope and pray for!
Resources: Huffingtonpost.com, nationalgeographic.com