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Zebras’ stripes discourage biting flies from landing
- zeristor 8y agoI wonder if CV systems will be similarly catastrophically perplexed? Imagine laying out the zebra rug for an Amazon drone delivery
- ipsum2 8y agoNo, its pretty obvious to recognize a zebra using a neural net (e.g. resnet)
- zeristor 8y agoI meant with regards for reference for landings, although I imagine a drone could look around, it’s far larger than a fly.
- curtis 8y agoI've wondered if you could do something similar for keeping birds from landing on flat elevated surfaces. I wasn't thinking stripes though, more like reflective holographic surfaces so the birds couldn't even identify the flat surface as flat. I'm inclined to believe that the crows would figure it out sooner or later though.
- heavenlyblue 8y agoBut is it as obvious to tell a distance to a zebra given it’s image?
- pferde 8y agohttps://thiszebradoesnotexist.com/ https://thiszebradoesnotexist.com/
- gpderetta 8y agohttps://en.m.wikipedia.org/wiki/Dazzle_camouflage https://en.m.wikipedia.org/wiki/Dazzle_camouflage
- darpa_escapee 8y agoThe study in the article tested this hypothesis and refuted it.
- thethirdone 8y agoIt in fact did not test anything about dazzle camouflage. The study [1] (linked by the linked article) did test how predators vision works and determined that Zebras camouflage doesn't serve much purpose at long ranges, but doesn't prove anything about shorter ranges where dazzle camouflage may make it easier for zebras to run away because predators aren't following them accurately. [1]: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0145679 https://journals.plos.org/plosone/article?id=10.1371/journal...
- amvalo 8y agoThis is essentially the mechanism the article describes... I think the most plausible explanation is that it's dazzle camo, the question is what species does it dazzle?
- skookumchuck 8y agoI definitely want a zebra striped T-shirt now!
- danamkaplan 8y agoI don't where I heard this, or if it is true, but it has been my favorite (maybe fake) animal fact: There is a reason the stripes are BLACK and WHITE. One absorbs the light and the other reflects, which in turn makes a slight difference of air temperature right above the skin surface. The difference of temperatures in certain areas cause (slight) differences in air pressure. This can cause a shallow "wind coat" around the Zebra (and more pronounced when the animal is moving) because of the air pressure deltas all over its skin. This helps Zebra's regulate body temperatures in some very hot climates.
- heavenlyblue 8y agoDid you at least do the math for that?
- sky_rw 8y agoThis theory is refuted in the very article you are commenting on.
- danamkaplan 8y agoMy favorite fake animal fact now.
- limbicsystem 8y agohttps://royalsocietypublishing.org/doi/10.1098/rsos.181325 https://royalsocietypublishing.org/doi/10.1098/rsos.181325
- ta1234567890 8y agoIf the theory of evolution is correct, then there is no why to any animal trait. There's no "reason" for the traits, it only happens that maybe some traits allowed the species to survive longer and so they are still around today, but that doesn't mean "someone" enforced a certain trait with a certain purpose. So, a more scientifically oriented title should be: What do Stripes do for Zebras? Shoo away flies.
- vntok 8y agoNo, that's a common mistake. In fact, there can be causation without a sentient causal entity. Zebras have stripes because their stripes shoo away flies, which helped previous generations of zebras who had stripes thrive and pass their genes forward. Why do zebras have stripes? Because they shoo flies away and evolution ensured that that helpful trait kept passing through descendants until every zebra had it as a dominant, visible trait. No one ever said there had to be "someone" somewhere to paint zebras black and white, that's just you using anthropomorphized evolution as a straw man/entity.
- laszlokorte 8y agoIt's still a philosophical debate if such an phenomenon can be seen as cause and effect. It's a similar problem as with teleological views in eg biology and medicine: "what's the task/purpose of the lungs?" - there is no predefined task.
- the_af 8y ago> Zebras have stripes because their stripes shoo away flies, which helped previous generations of zebras who had stripes thrive and pass their genes forward. Not necessarily. A trait may also be there simply because it's not actively harmful, or maybe because it's a useless side-effect of another trait that is beneficial. It may be that zebras have stripes because they are not harmful enough to prevent them from passing their genes forward. (of course, in this particular case the flies hypothesis seems more likely).
- lurquer 8y ago> which helped previous generations of zebras who had stripes thrive and pass their genes forward. You don't know that. The article doesn't even bother to test it. They've observed that stripes lead to fewer horsefly landings. Interesting. I guess. But, talking about evolution is a non sequitor. Show me the data where a zebra's fecundity is related to the number of horsefly bites it receives. There isn't any. One can speculate about such things. But, if one wishes to be scientific, test to see if there is a measurable effect. For all we know, zebras with MORE horsefly bites are MORE likely to reproduce. There simply is no data in the article one way or the other. So bringing up evolution is just mindless unscientific just-so-storytelling.
- deburo 8y agoInteresting theory. Also surprising that the counter-measure to disease-carrying flies is not a stronger immune system but something that gets them fewer bites. EDIT: but thinking about it more, nothing says multiple traits can't gain traction as a consequence of deadly pressure. I guess I never thought that much about evolution!
- otikik 8y agoI thought it was for the same reason humans have stripes: http://mentalfloss.com/article/65092/our-skin-covered-invisible-stripes http://mentalfloss.com/article/65092/our-skin-covered-invisi...
- notjtrig 8y agoIt's the same reason humans paint stripes on their bodies https://www.techexplorist.com/body-painting-protects-bloodsucking-insects/20272/ https://www.techexplorist.com/body-painting-protects-bloodsu...
- atoav 8y agoEvolution doesn’t answer to a single why question. Maybe the stripes have been useful to the zebra population’s survival, maybe not – but it is quite clear.that there is no singular reason but a bundle of things. E.g. the stripes make zebras harder to distinguish in a herd, which certainly lead to some percentage of survival. Flies too? Cool! But answering it as if there was some intention behind it? That is not how evolution works. Evolution doesn’t care and has no sense of meaning, like in genetic algrotihms it is just about which patterns survive, which die and which remain as a funny annecdote with no practical effect.
- ARandomerDude 8y ago> the stripes make zebras harder to distinguish in a herd, which certainly lead to some percentage of survival From the article: > Amanda Melin of the University of Calgary recently showed that lions and hyenas can’t even make out the stripes unless they get very close.
- everdev 8y ago> unless they get very close Sounds like it could still influence hunting as the predators have to get very close to make a kill
- gridspy 8y agoWhile you raise a good point about evolution being inscrutable - the stripes do effect files... " By watching and filming the stable’s horses and zebras, the team confirmed that horseflies were much worse at alighting on the latter. The flies had no problem finding the zebras or approaching them, but couldn’t stick the landing. “You get a quarter as many landings,” Caro said. “The flies just can’t probe for a blood meal with the zebras.” " I think the evolution angle relates to the question "Why did this trait evolve? What function does it serve?" with a potential Answer "It repels flies."
- atoav 8y agoMy point might have been unclear, but I didn’t doubt the usefulness of the stripes in even a slight way. My critique was pointed at the wording. IMO it is not about why a trait evolved – there are many useless traits that envolved somewhere during special conditions and after these conditions change remain for a eternity or suddenly find a new usefulness in changed circumstances. This means pinpointing such a trait down to a single why is not a good representation of reality. Are such observations valuable? For sure! Nature developed amazing strategies for all kind of things and not looking at these would be a waste. I’d just be a bit more cautios with quick conclusions that involve meaning and answering why-questions, that’s all
- gridspy 8y agoThe most interesting parts (to me): "By watching and filming the stable’s horses and zebras, the team confirmed that horseflies were much worse at alighting on the latter. The flies had no problem finding the zebras or approaching them, but couldn’t stick the landing. “You get a quarter as many landings,” Caro said. “The flies just can’t probe for a blood meal with the zebras.” “When we looked at the videos, we found that the flies simply aren’t decelerating when they come in to the stripes,” Caro said. Either they miss and overshoot the zebras, or they bump into the hides and bounce off. Something’s clearly throwing them off, but the details are still a mystery. Caro said that they might treat the black stripes like a pair of trees, try to fly between them, and end up colliding with the white stripes. Alternatively, the stripes might mess with their optic flow—their sense of objects moving across their visual field.
- drcode 8y agoI think flies can detect carbon dioxide levels to find their hosts (https://journeynorth.org/tm/crane/co2_traps.html https://journeynorth.org/tm/crane/co2_traps.html) Why is this fact never mentioned in this article, and did they do any analysis on how wearing a coat can affect CO2 levels around a horse's body?
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- proee 8y agoWhy didn't buffalo and bison evolve to have stripes? Seems they would benefit from having them.
- mhb 8y agoAlso the ability to run 60 MPH.
- the_af 8y agoI don't think that's how evolution works. Species don't gain traits that would benefit them. "Why didn't they?" seems like the wrong question :)
- kirre245 8y agoIn the article it is mentioned that zebras have shorter hair which makes them more vulnerable to the flies. You could ask why didnt they just grow longer hair? Well probably for something else it was important to have short hair.
- b_tterc_p 8y agoLocal climate feels like a probable answer
- lexxed 8y agoSo if i go to the jungle i should dress like a zebra