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Science Technology

Scientists Dressed Horses Like Zebras To Figure Out Why They Have Stripes (vice.com) 101

Why do zebras have stripes? From a report: Evolutionary biologists have proposed many possible theories, such as camouflage or vision aids for recognizing individual zebras. But in recent years, pest control has emerged as the leading explanation for zebra stripes. Researchers led by Tim Caro, an evolutionary ecologist at UC Davis, set out to test this idea in the field. The results, published Wednesday in PLOS ONE, reveal that stripes are a powerful deterrent to horse flies, a common nuisance that suck blood and bite flesh. The experiment managed to find the most delightful way to help explain these uniquely patterned coats -- by getting horses to cosplay as zebras.


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Scientists Dressed Horses Like Zebras To Figure Out Why They Have Stripes

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  • by Anonymous Coward

    Not enough to dress themselves up as zebras, now they are doing it to horses?

  • I remember reading (Score:5, Interesting)

    by DaMattster ( 977781 ) on Thursday February 21, 2019 @10:55AM (#58157702)
    I remember reading somewhere that the stripes were a product of evolution. Apparently, it is to confuse their primary predator, the lion. Since lions see only in black and white, the stripes are designed to confuse and disorient the lion.
    • Re: (Score:2, Informative)

      by Anonymous Coward

      This too is a product of evolution. Flies are just a worse scourge on the zebras than lions...

    • by sjbe ( 173966 ) on Thursday February 21, 2019 @11:12AM (#58157784)

      I remember reading somewhere that the stripes were a product of evolution. Apparently, it is to confuse their primary predator, the lion. Since lions see only in black and white, the stripes are designed to confuse and disorient the lion.

      Yes that is one theory. However it hasn't really been objectively verified. Kind of hard to do a double blind study on something like that if you get what I'm saying. That theory might be true or it might be completely irrelevant to how it happened. Most zebras are not killed by lions so it's quite plausible that lions did not create a significant evolutionary pressure regarding the stripes.

      • by Anonymous Coward

        You can see something like this in the Serengeti - the zebras will stand shoulder to shoulder facing different directions. Obviously it does not really hide the fact that there are zebras, what it does is confuse the predators as to the numbers that are there, and makes it harder to distinguish individuals to target - the first step in isolating a victim from the herd.

        However, considering the Serengeti is right in the middle of tsetse fly territory - the lowlands around it are infested - it makes sense as a

      • by alvinrod ( 889928 ) on Thursday February 21, 2019 @12:01PM (#58158050)
        It’s not quite correct but it has been researched. Zebras’ stripes do help them evade lions but not because lions can only see black and white, but because the stripe pattern makes it difficult for lions to identify a single zebra among the herd. The pattern makes them all blend together and confuses the lion enough to let a zebra escape when the lion hesitates or miscalculates.

        To test this theory some researchers painted a big stripe (I think it was red) on one zebra in a herd. The lions had no problem killing that one because it stood out and they could track it in isolation even when it was among other Zebras. There may be other benefits to Zebras having stripes, but we do know that it is an adaptation against primary predators.
        • Now I know where Roddenbery got some of his ideas.
        • Didn't they do something similar with ships in WW II? Paint them with funny patterns to confuse subs or enemies trying to target them?

          I think something similar gets done when car companies test prototypes on the public streets, they give them these weird zigzag paint schemes which I think is meant to confuse the autofocus on cameras.

        • The fly articles say they think it helps against flies because of their crappy vision... something about the stripes makes it so they can't calculate how to land. They swerve or bounce off zebras.

          I've heard the part about lions, too. Seems like the stripes have a few uses. And I think they mention it keeps zebras cooler than their often mostly dark colored cousins.

          It's strange that not more animals have black and white stripes... but there are a few. I wonder what studies are done with them.

      • How about scientists make it a more interactive study.

        I've been kind enough to ship a set of Zebra patterned lab coats with pockets filled with excrement to them to test for fly and lion abatement testing..

        All in the name of science of course.

        Insert your favorite lawye...er scientist joke here.

      • You can't test the lion-killing theory but you can test the horsefly theory, so that's what gets tested. Sort of like the drunk looking for his dropped keys waaaaay over there because there's a street light at that spot.
    • Not color blind (Score:5, Informative)

      by sjbe ( 173966 ) on Thursday February 21, 2019 @11:28AM (#58157858)

      Since lions see only in black and white,

      Lions see color [lionaid.org] just fine. Not quite the same as us but definitely not black and white.

    • by Thud457 ( 234763 )
      a lot of room for follow-on studies:
      1. compare incidence per capita of lion attacks on zebras vs horses
      2. dress horses up with tiger stripes
      3. dress horses up with cheetah spots
      4. dress horses up a penguins
      5. dress zebras up as horses
      6. dress lions up as zebras
      7. dress scientists up like horses
      8. dress horses up as scientists - compare efficacy of acquiring grants
      9. dress monkeys as cowboys and train them to ride dogs like horses [google.com]
    • Except lions, like all cats, can see colours, just not as many as a human can. This can be attributed to more rods in the retina to aid hunting in low light conditions.

    • Yes, horseflies should be able to evolve faster then the zebras to overcome such defenses. Lions make more sense.
    • I remember reading somewhere that the stripes were a product of evolution.

      Everything about an organism is a product of evolution.

  • Are the black stripes wrongfully profiled by the flies to attack them more often than the white.

  • Would not the better question be: what selective advantage did stripes provide?
    • Because it's more concise than "what selective advantage did stripes provide" and conveys pretty much the same idea to the expected audience. It's also a simpler and less technical variant of the question, so it appeals to a broader audience.

  • I still do not fully understand the evolutionary reasoning here. If horse flies are a "nuisance", why was there evolutionary pressure to avoid them?

    Generally speaking, according to the point equilibrium evolutionary theory, there should only be a trivial level of positive selection for traits that reduce trivial problems, and the selection should disappear once the problem disappeared. Are horse flies a continuous and meaningful problem for zebras? Furthermore, there cannot be an initial barrier to the posi

    • by Junta ( 36770 )

      Biting insects are merely a 'nuisance' when not carrying an epidemic or with reasonable feeding levels.

      Biting insects may have propagated a devastating plague applying pressure to the population. The warm climate might have also facilitated an overpopulation of biting insects so severe it would actually substantially impact the nourishment of the animals they fed on.

    • by icejai ( 214906 )

      Moose calves die if they have too many ticks.

      https://www.theatlantic.com/sc... [theatlantic.com]

      I don't know much about horse flies though.

      • Yes, exactly. Ticks are well known to cause serious issues and serve as a vector for many diseases, Lyme disease being the most well known. But I've never heard of horseflies doing the same, and they exist all over the world. I would also expect many different species to develop horsefly-specific traits if they were such a problem as well, not just zebras, but I haven't heard or seen anything about that either.

  • Not new (Score:5, Informative)

    by Teun ( 17872 ) on Thursday February 21, 2019 @11:42AM (#58157930)
    Zebra-style horse blankets have been available since a couple of years and precisely for this reason, get less trouble with flies.
    • by Anonymous Coward

      If I were a fly, I would avoid having to deal with blankets too!

      • Yes it's more an indication of the horse flies ability to distinguish between easy and hard prey, and their ability to communicate with one another.
    • by RobinH ( 124750 )
      That's interesting information, but a scientific study should be a little more rigorous than "Do this one amazing thing to stop horse flies from biting your horse!"
  • What about zebra flies?

  • Is this a follow up to the experiment where they dressed Chris and Steve-O up as a zebra to see if they attracted lions?
  • So if you are in an environment with lots of flies would wearing clothing with black and white stripes help for humans as well?
    • by HiThere ( 15173 )

      Definitely. Where ever you're wearing the clothing the files wouldn't bite you. Just be sure to also wear gloves and a decent head covering. And seal the cracks.

      FWIW, some flies are attracted more by scent than by color. But clothing is still a defense.

  • by jbmartin6 ( 1232050 ) on Thursday February 21, 2019 @01:28PM (#58158640)
    Not questioning the conclusion, I just wonder why the other animals living in the same environment don't show the same sort of adaptation. Perhaps other species have stronger pressures from other threats. Or maybe a favorable mutation in some proto-zebra.
  • ...then prisoners would ride.
  • Of the 3 stooges painting some horse with stripes to sell to someone?? Or them buying some horse painted like that?

Solutions are obvious if one only has the optical power to observe them over the horizon. -- K.A. Arsdall

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