Darwinism News

Stripes offer no advantage to zebra?

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From Eurekalert:

Stripes might not offer protection for animals living in groups, such as zebra, as previously thought, according to research published in Frontiers in Zoology. Humans playing a computer game captured striped targets more easily than uniform grey targets when multiple targets were present. This rebukes assumptions that stripes evolved to make it difficult to capture animals moving in a group.

Rebukes? Hey, guys, this is St. Darwin of Sandwalk we are talking about!

Anna Hughes, University of Cambridge, says “We found that when targets are presented individually, horizontally striped targets are more easily captured than targets with vertical or diagonal stripes. Surprisingly, we also found no benefit of stripes when multiple targets were presented at once, despite the prediction that stripes should be particularly effective in a group scenario. This could be due to how different stripe orientations interact with motion perception, where an incorrect reading of a target’s speed helps the predator to catch its prey.”

Stripes, zigzags and high contrast markings make animals highly conspicuous, which you might think would make them more visible to a predator. Researchers have wondered if movement is important in explaining why these patterns have evolved. Striking patterns may confuse predators and reduce the chance of attack or capture. In a concept termed ‘motion dazzle’, where high contrast patterns cause predators to misperceive the speed and direction of the moving animal. It was suggested that motion dazzle might be strongest in groups, such as a herd of zebra.’ More.

But how did they find this out? Not from lions, it seems. “A total of 60 human participants played a game to test whether stripes influenced their perception of moving targets .” In short, they did all their research on humans, and natural predators of zebras were not consulted.

They could be right, but for now, file under: Next time, go to the source.

This is one of the disadvantages of the “Humans are just like other animals” thesis. The thesis makes it easy to miss the obvious point that the human may be approaching the task in quite a different way and with different concerns from those of a hungry pride of lionesses with cubs to feed.

See also: Talk to the fossils: Let’s see what they say back. Evolution is not what we have thought.

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5 Replies to “Stripes offer no advantage to zebra?

  1. 1
    Robert Byers says:

    Interesting thread and why creationists would figure this out better. Colours in nature, in a post fall world, are real needs. They always have a meaning. God has a system in bodies that allowed to to get the colours they need for life.

    Horses are all about running fast and duration. This is a post fall adaptation and probably post flood.
    They are herd creatures originally. The post flood world was full of predators and so the horses/zebs were always moving in a herd. The stripes for sure distort a predator who while running is aiming at a horse in the herd.
    its common that the movement of a herd confuses the predators and so all the more the stripes blind the actual outline of a horse. Ots blurry.
    Deer do this and many African creatures as seen on nature shows.
    Computers are incompetent. They are wrong.
    The stripes simply blur the shape of the horses while running in a herd. Not alone.
    Creationism to the rescue.

  2. 2
    Mapou says:

    You crack me up, Byers.

  3. 3
    mahuna says:

    OK, so why don’t ALL herbivores that travel in groups have zebra stripes? Has anyone EVER done any actual studies of kills per chase by species of prey? And how about kills by predators other than lions? Do stripes confuse leopards and cheetahs? How about wolves?

    Giraffes have cute spots and an apparently worthless white belly. Fish and military aircraft have light colored bellies because some of their attackers hunt from below, and light bellies blend with the sky. But adult giraffes can kill lions (and leopards and cheetahs and hyenas etc.).

    So I think it’s just decoration. Humans WANT there to be some practical purpose for odd bits of Nature, but that doesn’t prohibit Nature from doing impractical things. And why are there more than 1 species of deer/antelope kinda beasties? Shouldn’t Nature have sorted out the perfect pack herbivore 20 million years ago, so the Fittest could drive all the less perfect subtypes to extinction?

  4. 4
    Robert Byers says:

    mahuna
    A horse has no protection except in its power of running. Its defined as a fast, endurance, creature. its not like other herd animals.
    Then remember the stripes came in a more rich world. A world of serious pradators and many now extinct. The fossil record sho\ws many types and there would be many. Horses main day event was running with the herd from everybodt. Not a few lions and cheetahs.
    White tailed deer also have a tail that conduese for those coming after them if running in groups.
    The stripes are for practical reasons of survival. in fact all horses show they once also had stripes. Remnants still kick in now and then.
    Clearly the stripes confuse the form in a running blur and don’t allow needed focusing for another creature after them. Simple.

    The best answer is the vsimple first.

  5. 5
    Silver Asiatic says:

    mahuna

    So I think it’s just decoration. Humans WANT there to be some practical purpose for odd bits of Nature, but that doesn’t prohibit Nature from doing impractical things. And why are there more than 1 species of deer/antelope kinda beasties? Shouldn’t Nature have sorted out the perfect pack herbivore 20 million years ago, so the Fittest could drive all the less perfect subtypes to extinction?

    My initial degree work was in the arts and the first thing I noticed when taking up science around 15 years ago was that the majority of science-math-engineering guys (it’s a male world) I work with had zero understanding, knowledge or appreciation of art – of any kind. Drama, sculpture, poetry, painting, serious music … they never encountered it.

    When you’re trained in the arts, however, and you take a look at nature – it becomes blatantly obvious about what is going on. It’s a masterpiece – the work of a colossal genius.

    I used to burst out laughing at my science colleagues who simply couldn’t recognize any of the beauty they were in the process of reverse-engineering or reducing to particles.

    A great work of art is irreducibly complex. It can’t be built by combinations at the molecular level. It’s like an organism — it can only fully be understood in it’s wholeness, not as the sum of individual parts.

    The weird and amazing variations in nature? They’re evidence of design. Decoration and beauty of the whole biosphere, not reduced to practical function alone.

    That’s just an example of how Darwinism impoverishes the world and humanity in general. Everything that exists, supposedly, exists only for survival and reproductive advantage. A multi-dimensional reality is artificially reduced to one-dimension. I think this is because a lot of people can’t handle anything more than that. They can only fit a reductionist worldview in their heads.

    I don’t know how anyone can live like that. It’s an absolutely miserable condition.

    There’s no love in atheism. It’s just nihilism and despair and darkness.

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