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Fear of Snakes May Have Driven Pre-Human Evolution 553

Posted by Hemos
from the snakes-on-a-plane dept.
Krishna Dagli writes "An evolutionary arms race between early snakes and mammals triggered the development of improved vision and large brains in primates, a radical new theory suggests. The idea, proposed by Lynne Isbell, an anthropologist at the University of California, Davis, suggests that snakes and primates share a long and intimate history, one that forced both groups to evolve new strategies as each attempted to gain the upper hand. Early primates developed a better eye for color, detail and movement and the ability to see in three dimensions — traits that are important for detecting threats at close range. Humans are descended from those same primates. "
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Fear of Snakes May Have Driven Pre-Human Evolution

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  • by Roody Blashes (975889) on Monday July 24, 2006 @09:05AM (#15768852) Homepage Journal
    Unfortunately for the bible-thumpers, this isn't actually a theory, it's just an idea. The idea that among a litany of predatory creatures human beings were primarily pushed by one - that although fear-inducing is relatively harmless on the scale of tribes and socities - is a bit of a stretch.

    If this is pursued by scientists we will likely find that, yes, there are specific factors involved in competition between humans and snakes that drove specific selections that persist in modern humans, but to suggest that all of "pre-human evolution" was driven primarily by snakes is a bit silly.
  • by Anonymous Coward on Monday July 24, 2006 @09:07AM (#15768865)

    So what you are saying is that our fear of snakes caused us to incorporate them into our myths and legends as the stereotypical "bad guy"? Makes sense to me.

  • by Black Parrot (19622) on Monday July 24, 2006 @09:12AM (#15768900)
    Uhmmm... the hypothesis, even if correct, doesn't say that snakes lost their legs due to meddling in the affairs of a couple of innocent humans.
  • Re:It makes sense! (Score:3, Insightful)

    by smooth wombat (796938) on Monday July 24, 2006 @09:33AM (#15769054) Homepage Journal
    Given the instinctive fear of snakes that humans possess,


    Not all humans have an instinctive fear of snakes. For instance, I've taken pictures of some local snakes at a range of about 6". These snakes are not poisonous so I know the worst I could get from them is a nasty bite.

    If these were poisonous snakes would I still be that close? Probably not but that's simply a healthy respect for the snake and not a fear of it. If you take your time and don't ruffle its scales you can get close to most any snake. If these were copperheads or rattlers I could probably, comfortably, take pictures at a range of 12" or so.

    Granted, there are those that the mere picture of a snake will send them into a tizzy but with therapy can overcome that fear. Same with spiders and other crawly things.

    Personally, I believe that the reason some people fear snakes is three-fold. First comes from the bible and it's boogeyman characterization of a snake being an evil thing. Second, from all the bad movies showing snakes being evil creatures. Third, from parents telling their kids that snakes are evil things (which comes from points 1 and 2.).

    If people are brought up that snakes should be respected and not feared, many problems between snakes and people wouldn't be around.

  • by Black Parrot (19622) on Monday July 24, 2006 @09:39AM (#15769118)
    > Well, the article says that recent research shows that reach-and-grasp did not evolve at the same time as the better vision, which makes it unlikely that they evolved for the same purpose.

    I'm not sure that's a good argument. It's not like evolution happens on demand.

    Our own upright posture, opposable thumbs, and big brains didn't all evolve at the same time, but we still build our lifestyle around their conjunction.

  • Re:2D-3D? (Score:3, Insightful)

    by Roody Blashes (975889) on Monday July 24, 2006 @09:41AM (#15769130) Homepage Journal
    Within the context of the original post (the evolving to see in 4 dimensions thing), it suggests to me that he meant seeing all 3 spacial dimensions. Stereoscopic vision is not the same as that. It just means your brain is capable of recognizing angles on objects and interpreting them for you as some level of depth. People with poor depth perception don't necessarily have anything wrong with their eyes. They see the same thing everyone else does, their brains just don't interpret the angles properly.

    You can prove quite easily that you can only see two dimensions of space. Simply place a cube on a table, lower and center your vision so it's pinpointed right in the center of one side, and note that you see a square, not a cube. Without the angles to suggest depth, you're not capable of perceiving three dimensions at all.
  • by plague3106 (71849) on Monday July 24, 2006 @09:56AM (#15769234)
    Well we see proof in the world around us that Darwinism is possible. We have yet to see "something pop out of nothing" as creationism suggests.

    So while Darwinism is just a theory at this point, its a theory well grounded in current scientific observation, while Creationism is not..
  • by mjm1231 (751545) on Monday July 24, 2006 @10:24AM (#15769427)
    Losing an existing trait does not require there to be an advantage to losing it. All that is required is that having the trait no longer provides an advantage.
  • Re:Why snakes? (Score:1, Insightful)

    by DrFalkyn (102068) on Monday July 24, 2006 @10:40AM (#15769530)
    Good point. Another thign that used to intrigue me about human evolution is how crummy our physical abilities are compared to most animals that would somehow compete with us. Why didn't the tribes of early humans all get eaten by lions or other speedy predators? And on the predator side, how would we have been able to catch up with zebras and antelopes? We are slow, weak and are poor tree climbers. It puzzled me until I learned about how much more endurant we are compared to most other animals. Theres not many mammals that are going to be able to run a marathon like we do. Endurance is not going to help the prey very much unless they are of comparabnle speed to their predators. But if a predator can run down and track the prey until they are exhausted(as some hunter-gather tribes in African have been documented to do), then it becomes a advantage even if the prey is alot faster than the predator. As for defending against predators, group size was probably key. A pack of 5-10 humans reasonably equipped even with simple weapons would probably be enough to take on a single lion or other dangerous predator, or at least strongly discrouage them from attacking. I guess eyesight would also help with avoiding predators. My own pet theory is the reason why male humans have better nightvision and females have better color discrimination is that men stood watch at night and while females kept an eye out for predators during the day while the men were hunting. Thats also probably why men tend to be nightowls (I know I am :-)
  • by digitaldc (879047) * on Monday July 24, 2006 @10:50AM (#15769606)
    From: http://www.janegoodall.org/chimp_central/chimpanze es/behavior/rain_dance.asp [janegoodall.org]

    An excellent example of a respect and intense curiosity of chimpanzees to an animate object is in their reaction to snakes, particularly pythons. Pythons could pose a threat to young chimpanzees, but it is not likely that any snake would take on an adult. However, when a single individual or group of chimpanzees encounters a python (even a small one), the reaction is remarkable. One would expect the chimps to issue alarm calls to warn others and as an expression of their fear, but then to move well out of harms way as soon as possible. Predictably, the chimpanzees do issue a specific vocalization called a snake wraa, but when it is uttered, the group often draws near, to stare at the snake. Some climb above if possible for a better look. Typical facial expressions are those of fear and curiosity. Physical reassurance contact is often made (especially mutual embracing), and eye contact among individuals is frequent. After tens of minutes, members finally begin to disperse. Some individuals however, (Skosha and Apollo, for instance) show exaggerated and prolonged interest. Both call time and again even after the other individuals have moved well away. I have seen both stay and stare and call for as long as 30 minutes.
    It is difficult to explain why chimpanzees react to pythons in this way. It appears to be much more than keeping a close eye on a possible threat, as many species do. It also seems a great waste of energy and time. If pythons are dangerous, it would make much more sense to alarm call and move away as quickly as possible.
  • Re:2D-3D? (Score:3, Insightful)

    by Fordiman (689627) <fordiman@gmailGI ... minus herbivore> on Monday July 24, 2006 @10:51AM (#15769626) Homepage Journal
    No. Stereoscopic vision gives you the ability to percieve distance in a 3d environment. You're still only /seeing/ in 2-d. Specifically, two 2-d images. The 3-d you percieve is those two images as processed by your brain.

    Hence percieve, not see.
  • I always thought that 3D vision was an evolution for predators to be able to calculate distance from their prey to their current position. And pray has eyes on the sides because it allows them to have a bigger span of vision to catch those predators when coming.

    Now, for the color, I thought it was a trait for some fruit-picker beings, to be able to recognize good fruits from bad ones.

    I never imagined it was for the snakes :P
  • by hey! (33014) on Monday July 24, 2006 @10:55AM (#15769652) Homepage Journal
    I think it'd get boring. Eternal life, I mean. No, seriously. After a while, you've done everything. Even God's Love has to get old eventually.

    This is the kind of thinking that is central in stories of this kind. Immortality, at least if other aspects of our existence aren't also changed, would be a form of suffering worse than death.

    However, it should be pointed out in all fairness that boredom is a problem that is tied to our brains. It's a hardware problem. Our brains are wired to stop paying attention after a while, to experience suffering without regular doses of novelty.

    It could even be that this need for novelty is in fact the core of original sin, as well as of our quest for wisdom. After all, what's so bad about toil? It's not so bad for a while, but it gets old fast. What's so bad about old ideas and ways of looking things? They become unbearably dull after a while.

    Orthodox Christianity teaches not just the salvation of the soul, but the ressurection of the body. However, the ressurected body is thought to be transfigured. After all, we are told we in Mark 12:25 that we will live "like angels which are in heaven". Inattention and boredom are not consistent with an angelic lifestyle, so presumably the neural circuits for those traits are to be replaced or upgraded.

    Likewise, the same should be true for technological approaches to immortality, such as nano-technology or transferring your consciousness to a machine. If the tendency to get bored is fundamental to the human identity, you can't live an immortal existence as a human without being subject to unending torment. So whether by technological means or miraculous means, a life of unending bliss also entails giving up certain aspects that we may think of as being fundamentally human.
  • by Roody Blashes (975889) on Monday July 24, 2006 @11:05AM (#15769709) Homepage Journal
    Ignoring the fact that your entire post is false, and apparently nothing more than a nasty, disrespectful attempt to mislead people about the topic, it wouldn't matter if scientific findings DID prove the bible correct word for word. That would simply be the way the universe is. So be it.

    Unlike religionists, real scientists just want to know the truth, and they're not scared that it might shatter their own preconcieved notions, so they don't "shift" the truth based on that (and when they do, they get found out, discredited, and made a laughing stock).
  • No wonder (Score:5, Insightful)

    by Tony (765) on Monday July 24, 2006 @11:30AM (#15769926) Journal
    And we wonder why there is a debate between Darwinism and Creationism.

    No, we don't.

    There is a debate because creationists have manufactured a debate. There is internal debate among biologists about some of the mechanisms of evolution and natural selection, but that doesn't require creationism in the slightest.

    Those who espouse creationism do so out of a bond to a cult. "If it contradicts what is literally in my Bible, it is false." That is an aspect of a cult: to deny the evidence when faced with it. (There's also the whole personality-driven thing, in which Jerry Falwell, Ralph Reed, Pat Robertson, and their demons play a major part.)

    Now, it's your chance to respond, "That is just what Darwinists do!" As if stating it as fact makes it fact.

    The funny thing is, Darwin didn't create the theory of evolution. It existed for years before Darwin boarded the Beagle. He came up with the concept that is the core of current evolutionary theory, though: that evolution is driven by natural selection. "Natural selection" is merely the idea that some phenotypes within a population are better adapted at survival than others, within the current environment. When there is little selection pressure, many phenotypes may survive, allowing genetic diversity within a population. When the environment changes, certain phenotypes may provide better adaption to the environment. When two different phenotypes provide survival traits, you may end up with a divergent population, resulting in two species where there used to be one.

    Most modern biologists accept this as the driving force behind evolution. There are details that are argued, and there is always points of debate, but the fundamental theory is laid down more-or-less as Darwin painted it.

    . . . but are in actuallity mere theory and speculation.

    That pretty much removes you from any serious debate. The Theory of Gravity is just a theory, but I don't see you jumping off a very tall cliff with no parachute any time soon. You should go figure out what a "theory" is in the scientific sense before making stupid statements like this.

    The way science works is this: if you have an theory that fits the facts, and accurately makes predictions (which is required for testability), that theory survives. Once that theory fails a prediction, the theory is either modified or discarded. Hopefully, there are competing theories to take its place that provide a more accurate prediction mechanism.

    The theory of evolution through natural selection has survived a long, long time. It is probably one of the most-tested theories ever. One example: it predates modern genetic theory, and yet the implications of evolution on genetics (the predictions) are borne out by modern genetic research.

    The problem with the creationists' appeal to a divine intervention is simple. For it to be a viable scientific theory, it must make predictions that can be tested for accuracy. There is no known method to accurately test for God. You might assume his existence, but you cannot test for him, the the best of my knowledge.

    The arguments of the intelligent design crowd invariably reduce to a simple logical mistake: we don't know how it happened, so it must've been God who did it. And when science, using its proven epistemology, pushes back the boundaries of knowledge, the ID crowd responds, "Oh, yes, well, we didn't quite mean that. We meant this other thing that you can't prove." It happened with "irreducible complexity" (which is nothing but the long-disproven "Only God could create the eye" argument gussied up with the terminology of microbiology), it happened with the catastrophists (who use catastrophism to prove the Biblical flood), and will most likely occur with the next pseudo-scientific attempt to subvert education.

    Ultimately, that's what this is about: the ability to control the next generation through education. If they are taught to think for themselves, to reason about problems instead of appealing to
  • by IAmTheDave (746256) <basenamedave-sd@@@yahoo...com> on Monday July 24, 2006 @11:31AM (#15769930) Homepage Journal
    I think it'd get boring. Eternal life, I mean. No, seriously. After a while, you've done everything. Even God's Love has to get old eventually.

    Meh, depends on how you think about it. I doubt "eternity" - and I sure hope their is one, and that I get to go to the good part - is hardly based on the same idea of linear time that we now understand. Our perception of time requires a beginning and an end. Eternity - the way I've figured it - probably exists outside of linear time, a sort of everything-happens-at-the-same-time kind of non-linear eternity.

    But who knows. Right now, my biggest fear is, come my death, meeting Allah, Joseph Smith, L. Ron Hubbard, Buddah, Zeus, Zenu, or any other number of Gods or prophets I've chosen to not believe in, who will laugh and send me to whatever version of hell they sport.

    ME: Hey! Sup Allah, Mohammad... How you guys been?

    Allah: Wrong religion bitch!

    Me: *Shit...*

  • Snakes on Staff (Score:4, Insightful)

    by Doc Ruby (173196) on Monday July 24, 2006 @11:39AM (#15769984) Homepage Journal
    How come snakes are the ancient symbol for medicine [wikipedia.org] that we still use?
  • by Anonymous Coward on Monday July 24, 2006 @11:57AM (#15770149)

    As science advances, you're going to find more and more similarities between science and the Bible

    The Bible is so vague and contradictory at times, you could discover practically any conceivable notion to be true and someboody would be able to dig up something in the Bible that vaguely resembles it. It's like horoscopes, if you're vague enough and people want to believe, they'll contort the facts as much as is necessary to validate their beliefs.

    There's bits in Greek mythology about snakes being naughty, guess Zeus exists, huh?

    and will have to accept the fact that many of the things "discovered" by science were already known to Christians thousands of years ago.

    If I tell you that the next time you throw a die you're going to get a six, if it happens, did I know that it was going to happen? No, it was a wild guess. What matters is not how many times the Bible is correct, what matters is the ratio of correct assertions versus the number of incorrect assertions. Otherwise you can hook a random number generator up to an ASCII table and call that Truth.

  • by a.d.trick (894813) on Monday July 24, 2006 @12:01PM (#15770178) Homepage

    This 'bible-thumper' characher that keeps on popping up on slashdot seems to have about the same effect as the word 'terrorist' on just about any non-geek website. Use it in a derogatory manner, and you almost assured at least one insightful modding, at the expense of actual insight. (Yeah, I know this is slashdot and I should expect anything better from a website where posts about Bill Gates' penis get 'insightful').

    I'm guessing that your bible-thumper is one of those characters who thinks they know a lot about Christian Scriptures but really doesn't. I've seen these kind of people before, and yeah, they can be annoying; but their numbers pale in comparison to the number of people who think they know a lot about science and philosophy, but really don't. Have you ever started to get into a conversation about Plato with someone who says they read all sorts of philosophy stuff only to watch there eyes glaze over when you start to talk about his famous cave analogy. These kinds of people are a dime a dozen (hell, I've acted like that sometimes too) and it's not suprising that a few of them end up in Christian circles.

    The comments made about these so called bible-thumpers are strictly ad hominem and it's unfortunate to see them so much among the educated people here who really ought to know better.

  • by Shadowlore (10860) on Monday July 24, 2006 @01:23PM (#15770821) Journal
    Why should the threat of consumption from snakes (snakes! of all things!) have driven us to evolve incredibly good eyesight? Why not hearing? Why not some more obvious and simple snake defense mechanism (like, immunity from snake poison?) At no time in our evolutionary history did snakes actually represent a dominant predatory force (To deal with this, some "experts" claim generalization from dinosaur tails. Right). Just because it has the word "evolution" in it doesn't mean it's right.


    Regarding your idea of evolution, I'll paraphrase you:
    "The idea the evolution was a conscious process, and almost every instantiation of this idea, is total crap, and should be treated this way."

    You, like millions of others, make a mistake in thinking evolution is a conscious process. With genetic manipulation it may become that way in humans, but otherwise it is not. It isn't like the proto-humans/early humans sat around and said "You know these snakes are a deadly threat. We shall form a comittee and decide on how best to evolve to defeat them.". If that had happened we would have snake venom immunity.[1]

    IF snakes were a deadly threat, than whatever provided an advantage in escaping the threat would have sufficed. If better vision provided "good enough" advantage for the being with those genes to pass on their DNA then that would happen (with regard to that threat). It could well be that several advantages produced a set of genes that provided multiple avenues of threat avoidance. Particularly if these advantages were useful for more than snakes.

    Evolution is explanatory, not proactive. Yet. Sadly, scientists working in the field often use stupid and ridiculous statemets such as "in response to" when they should be saying "as a result of...". The headline for the article here on /. also reflects this lack of understanding.

    If conceived of today evolution would be termed an "emergent phenomenon". The primary principle of evolution is "good enough". If it works, it works - that is all that is required. There is no planning, no intentional process.

    Regarding snakes being a threat ... you who live your your comfy controlled environment may not regard snakes as a threat. However, thos eof us who have had to live and work in open areas with posionous snakes know otherwise. Snakes are particularly deadly to smaller bodies such as children. Whether it be poisonous snakes or constrictors, if snakes are taking out younglings that lack the ability to get away (lack of perception, speed, recognition, whatever) then they certainly would be a factor in the evolution of creatures they consume.

    1) Venom immunity would not have sufficed. What good is immunity to venom if the wounds get infected and you die from infection? A Committe would have produced venom immunity and then we'd have died out from secondary snake bite infections. A clear example of the phrase "to each and every problem there is solution that is simple and obvious. Said answer is also wrong."

    Hearing would have been a likewise poor choice given the sensitivity and limited range of perception it would have produced. Early humans occupied multiple niches and thus were open to many predators of a wide range of "features".

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