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

Posted by msmash on from the mad-science dept.

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.


52 of 101 comments (clear)

  1. Friggin furries by Anonymous Coward · · Score: 1

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

    1. Re: Friggin furries by Calydor · · Score: 1

      I would assume that a fly is not smart enough to see from a distance whether something is natural fur and hide or an impenetrable blanket, so the scientists likely kept a close eye on the horses to see how many flies TRIED to bite them.

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    2. Re: Friggin furries by Mattcelt · · Score: 2

      I think this is more stripe-dressing scientists, but we might be splitting mares here.

    3. Re: Friggin furries by wanfuse123 · · Score: 2

      Yes they should have painted them instead, it's a stupid conclusion

  2. I remember reading by DaMattster · · Score: 5, Interesting

    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.

    1. Re:I remember reading by Anonymous Coward · · Score: 2, Informative

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

    2. Re:I remember reading by Thud457 · · Score: 2

      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

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      the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff

    3. Re:I remember reading by LynnwoodRooster · · Score: 2

      Reminds me of this Far Side cartoon...

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    4. Re:I remember reading by mrbester · · Score: 1

      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.

      --
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    5. Re:I remember reading by willy_me · · Score: 1

      Yes, horseflies should be able to evolve faster then the zebras to overcome such defenses. Lions make more sense.

    6. Re:I remember reading by pauljlucas · · Score: 1

      I remember reading somewhere that the stripes were a product of evolution.

      Everything about an organism is a product of evolution.

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  3. The next line of research... by magusxxx · · Score: 1, Funny

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

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    Care killed the cat, but satisfaction brought it back.
    1. Re:The next line of research... by DigiShaman · · Score: 1

      Clearly there's a discrimination against polka dots.

      --
      Life is not for the lazy.
  4. Many theories are out there by sjbe · · Score: 4, Insightful

    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.

    1. Re:Many theories are out there by Anonymous Coward · · Score: 1

      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 fly deterrent too. Apparently we owe the prevalence of magnificent big game in Africa, among other reasons, to the fact that the tsetse flies are dangerous (and annoying!) to large animals like cattle as well as humans, so human settlement was slow to take hold.

      I think the next step is to see if the same applies to smaller animals. take a cat, paint a white stripe down its back and see what happens...

    2. Re:Many theories are out there by alvinrod · · Score: 3, Informative

      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.

    3. Re:Many theories are out there by ContextSwitch · · Score: 2

      Now I know where Roddenbery got some of his ideas.

    4. Re:Many theories are out there by Calydor · · Score: 3, Funny

      I have here this tiger-repelling rock. You know it works because there are no tigers around.

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    5. Re:Many theories are out there by LostMyAccount · · Score: 1

      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.

    6. Re:Many theories are out there by omfglearntoplay · · Score: 1

      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.

    7. Re:Many theories are out there by aevan · · Score: 3, Informative

      Dazzle pattern camoflage.

    8. Re:Many theories are out there by ZoomieDood · · Score: 1

      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.

    9. Re:Many theories are out there by david_thornley · · Score: 1

      That's more of a WWI thing. I'm into WWII naval camouflage and I haven't seen an example of zebra dazzle camouflage then. The later war USN patterns, while you could call them dazzle patterns, were not the WWI jagged black and white stripes.

      --
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    10. Re:Many theories are out there by arglebargle_xiv · · Score: 1

      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.

  5. Not color blind by sjbe · · Score: 4, Informative

    Since lions see only in black and white,

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

  6. Why do we say "why"? by Potor · · Score: 1

    Would not the better question be: what selective advantage did stripes provide?

    1. Re:Why do we say "why"? by Potor · · Score: 1

      But "why" implies design, not random advantageous mutations.

      Or put differently: if we use "why", the only answer can be "evolution." Then everything else becomes "how" (the mechanism) and "what" (the advantage) questions.

    2. Re:Why do we say "why"? by Issildur03 · · Score: 1

      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.

    3. Re:Why do we say "why"? by Livius · · Score: 1

      No, "why" can be cause, not necessarily intent.

  7. Not sure if correct by TimothyHollins · · Score: 1

    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 positive trait, meaning that the stripes would have to emerge as an initial pattern immediately, it cannot have developed as first turning black and then developing white stripes (or vice versa) unless black (or white) colors also repel horse flies.

    1. Re:Not sure if correct by Junta · · Score: 2

      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.

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    2. Re:Not sure if correct by Riceballsan · · Score: 1

      Well the 2 main perks that can be are helps them breed, and helps them not die. Generally attraction also evolves in the same way. Animals are attracted to the mates that are most likely to deliver and raise offspring, as the animals that were attracted to mates that sucked at birthing/raising's offspring died. Generally speaking "Nuisances" are terms we use for things that are minor forms of potentially deadly problems. Say for instance it being cold outside is a "Nuisance" to humans, we usually slap on a coat or go inside. For a homeless person, without access to warm clothing that needs to stay in cold weather for a long amount of time, it can turn deadly. Likewise fly bites are a nuisance individually, animals wish to avoid them, because either a swarm of them biting could lead to serious injury/death, or just 1 carrying a deadly disease or parasite.

    3. Re:Not sure if correct by icejai · · Score: 1

      Moose calves die if they have too many ticks.

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

      I don't know much about horse flies though.

    4. Re:Not sure if correct by TimothyHollins · · Score: 1

      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.

  8. Not new by Teun · · Score: 4, Informative

    Zebra-style horse blankets have been available since a couple of years and precisely for this reason, get less trouble with flies.

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    1. Re:Not new by Anonymous Coward · · Score: 1

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

    2. Re:Not new by RobinH · · Score: 1

      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!"

      --
      "I have never let my schooling interfere with my education." - Mark Twain
    3. Re:Not new by HiThere · · Score: 1

      No. Common sense cannot trump rigorous scientific study. It can either agree or disagree, but when it disagrees, it's wrong. The earth does revolve around the sun.

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      I think we've pushed this "anyone can grow up to be president" thing too far.
    4. Re: Not new by wanfuse123 · · Score: 1

      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.

  9. Yeah but by bigdavex · · Score: 1

    What about zebra flies?

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    -Dave
  10. Wild Boyz research institute by Headw1nd · · Score: 1

    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?

  11. That's how you get skunks by sjbe · · Score: 5, Funny

    I think the next step is to see if the same applies to smaller animals. take a cat, paint a white stripe down its back and see what happens...

    They've tried that and it results in amorous skunks with bad French accents.

  12. Natural selection does not have intent by sjbe · · Score: 1

    ... or the adaptation worked out as intended

    There is no intent to natural selection. It happens but it's not a process with a design.

    1. Re:Natural selection does not have intent by Darinbob · · Score: 1

      Good point. I feel there's a whole lot of wishy washy handwaving done with evolution by people who don't have an indepth knowledge of evolution. I will agree I am someone who doesn't know it as well as many. I do see however many people who seem to have a superficial understanding and who have a lot of anthropomorphic views on it. Ie, that evolution leads from to better organisms, that some creatures are more evolved than others, that there's a "reason" or goal for evolution and that every facet of an organism has a purpose. This reaches levels of absurdity with sociology people at times, such as "what is the evolutionary purpose for grandparents?"

  13. Would this work for people? by Danathar · · Score: 1

    So if you are in an environment with lots of flies would wearing clothing with black and white stripes help for humans as well?

    1. Re:Would this work for people? by HiThere · · Score: 1

      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.

      --

      I think we've pushed this "anyone can grow up to be president" thing too far.
  14. Why not the others? by jbmartin6 · · Score: 2

    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.

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  15. Re:a fork from our self replicating era? by HiThere · · Score: 1

    They are, indeed, color blind, but if I understand correctly they're only red-green color blind, not totally so.

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    I think we've pushed this "anyone can grow up to be president" thing too far.
  16. Re:Years ago by HiThere · · Score: 1

    No, that's not the same experiment. That's showing that flies don't prefer white skin over black skin. The duplicate would compare the bites on a striped animal against the bites on a non-striped animal..and for picking the color of the non-striped animal the experiment you referred to (which I don't know about) would be valuable as a "don't care" modifier.

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    I think we've pushed this "anyone can grow up to be president" thing too far.
  17. If horses were zebras... by ItsJustAPseudonym · · Score: 1

    ...then prisoners would ride.

  18. Why do I have keep having visuals by pgmrdlm · · Score: 1

    Of the 3 stooges painting some horse with stripes to sell to someone?? Or them buying some horse painted like that?

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  19. Re:So painting horses in zebraface? by Tablizer · · Score: 1

    Crisscrossdressing is a sin, Son!

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