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Question Your World: How Did Zebras Get Their Stripes?

Sometimes a really small thing can make a very large impact. That's what scientists recently concluded when answering one of the age old questions that humanity has wondered since our earliest days on the plains of Africa, how did zebras get their stripes? Listen to this Question Your World radio report produced by the Science Museum of Virginia to learn more.

Few animals are as visually distinctive as zebras. These African animals have an amazing pattern that separates them from nearly all other creatures on this planet, but why? How did they develop their trademark look and what caused this to happen in the first place? Over the years many theories have been proposed:

  1. Camouflage
  2. Temperature regulation
  3. Social Hierarchy
  4. A pattern to confuse and distract predators

Well, there have been a lot of interesting conversations in the science world regarding these stripes, but in a recent survey an answer was produced and it certainly does not fit into any of those theories listed above.

Scientists at the University of California, Davis studied seven horse species around the world and did a correlative analysis on what else exists where they live. One thing that started to appear is the appearance of visual marks such as stripes in areas where there are high concentrations of biting flies. They observed that in regions where these bugs are more pervasive and present the markings on horses seems to get more noticeable too. After overlapping all the various data they were able to see that the more stripes a creature has the less likely it is to be bit by these irritating flies.

But why zebras? There are other horse species in the area. How come this particular species went with stripes while other donkeys and horses remain unaffected? This question can be answered by simply looking at the length of the hair on zebras. The mouth parts of the flies are long enough to get through the short hair and access the skin below. Horses with longer hair need not worry as much, but zebras were prime targets. So, over many generations of evolution zebras adapted to having very distinct stripes to avoid biting flies. Pretty amazing. Tiny fly, huge evolutionary impact!

Now that the age old question has been put to rest, a new one has been brought up. Why don't these flies bite striped areas? A great example of how science never allows for one question to be answered without bringing up another one.

So, in the meantime zebras, the Hamburgler, and Robin Thicke will apparently be able to deal with biting bugs, the rest of us better invest in some bug spray.

Article by: Prabir Mehta Science Museum of Virginia

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