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Thread: Fur/Hair pattern in humans?

  1. #1 Fur/Hair pattern in humans? 
    Forum Cosmic Wizard icewendigo's Avatar
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    We are familiar with animals being furry, but what caused humans to, mostly;
    1- have "long hair" on the heard(when not cut),
    2- no fur on most of the body(tiny skin hairs) and
    3- some hair only at puberty and only in specific regions (pubic hair, armpits,etc)?(Why?)

    We take it for granted thinking it makes sense because we're used to it, so all that appears to be normal from our perspective, but when you look at many mammals this pattern of hair is quite unusual.


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  3. #2  
    Forum Cosmic Wizard spuriousmonkey's Avatar
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    We have hair all over the body. Take another look at yourself.


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  4. #3  
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    Too much coffee spuriousmonkey, read #2.
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  5. #4 Re: Fur/Hair pattern in humans? 
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    Quote Originally Posted by icewendigo
    We are familiar with animals being furry, but what caused humans to, mostly;
    1- have "long hair" on the heard(when not cut),
    2- no fur on most of the body(tiny skin hairs) and
    I'm thinking clothing for this one. We must have been able to wear clothes for a long time before our minds matured. I'm hard pressed to think of any other naked mammals that aren't nocturnal or something like that.

    3- some hair only at puberty and only in specific regions (pubic hair, armpits,etc)?(Why?)
    From what I can tell, the purpose of these hairs is to help sweat to evaporate, rather than trying to keep you warm. Or else, why would it grow in your armpits? Letting your sweat drip onto a hair increases the surface area, making evaporation easier and faster, as well as increasing heat conduction with the air. This is part of why the heat sink attached to your computer's CPU usually has so many protrusions. It's to increase surface area.

    Ironically, the hair on the top of say... an African tribes-person's head would probably serve the same purpose most of the time. It's there to help them cool their head, rather than keep it warm. I'm pretty sure that male pattern baldness is more common in ethnic groups that come from cold climates than warm ones.
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    Natural dreds or afro is really excessive though. Our species grows head hair beyond function.

    It's funny that we typically assume head and facial hair evolved for human eyes, while forgetting animals have eyes also. IMO human hair pattern serves to identify us to other species. Predators learn which species not to mess with i.e. they learn that hominids without that mass of head hair are easily routed pushovers, while hominids with afro are surly buggers who swing sticks, throw rocks, use mob tactics. That's our hidden sting.

    The male baldness and concealed face could cause predators to single out those individuals in a group. That would be to our advantage, tactically and even genetically to the bald man who likely has some sons and daughters nearby he'd better sacrifice for.

    I wonder if the origin of male (hunter) hair cropping goes back so far, as a deceit against predators (prey)? If true it should correspond exactly with the development of spears. Of course hunters want to appear as harmless prey species.

    As for lack of general body hair, that could be an identifying trait too. Note that neanderthals, who wore clothes, did not loose so much body hair. In their case it's out of sight, and protects against the chafing of artificial skins.

    In any case, for animals to "know man" we must have set ourselves apart from other hominids somehow.
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    Pong, please. We have no idea how hairy neandertals may or may not have been compared to other hominids. For that matter we really do not know when any of the hominids really started to have a reduction in fur compared to other apes, and this makes speculating on the reasons for that loss difficult since we can't really pinpoint the environment and social conditions at the time. For example, your idea about identifying us to predators assumes that we were actually capable of reliably fighting off large predators at the time, which in turn assumes probably Homo erectus at the least. Most of the earlier hominids were smaller and there's a lot of evidence that they were regularly predated upon by large animals. So right there you're assuming you know the earlier hominids were much hairier than Homo erectus. And again: we have NO evidence either way of this. When artists imagine what these animals might have looked like everything in Homo tends to have less hair, but it's pure speculation.
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  8. #7  
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    Quote Originally Posted by Pong
    Natural dreds or afro is really excessive though. Our species grows head hair beyond function.

    It's funny that we typically assume head and facial hair evolved for human eyes, while forgetting animals have eyes also.
    True, but a lot of those other mammals don't have sweat glands, which is most of why you need eyebrows. Cancer patients often comment that one of the worst parts of going bald is getting sweat in your eyes.

    IMO human hair pattern serves to identify us to other species. Predators learn which species not to mess with i.e. they learn that hominids without that mass of head hair are easily routed pushovers, while hominids with afro are surly buggers who swing sticks, throw rocks, use mob tactics. That's our hidden sting.
    So you're going with the plumage theory? It could work. Maybe long hair also shows how genetically fit you are, like a male peacock? We might similarly ask why a horse or a lion has a mane.

    Quote Originally Posted by paralith
    . So right there you're assuming you know the earlier hominids were much hairier than Homo erectus. And again: we have NO evidence either way of this. When artists imagine what these animals might have looked like everything in Homo tends to have less hair, but it's pure speculation.
    I've often wondered about that. I watch documentaries about pre-humans sometimes, and I've often wondered what their justification is for drawing them hairless.
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    Lol okay I am wildly speculating. Granted.

    So we test my hypothesis. How? We're gonna have to grow dredlocks, hang around with chimpanzees, and condition local predators to leave us be: by hucking rocks at them and poking them with staffs. What do you predict will happen? Explain how the predators select their prey.
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    Quote Originally Posted by Pong
    Lol okay I am wildly speculating. Granted.

    So we test my hypothesis. How? We're gonna have to grow dredlocks, hang around with chimpanzees, and condition local predators to leave us be: by hucking rocks at them and poking them with staffs. What do you predict will happen? Explain how the predators select their prey.
    I think scent would be enough for most animals. I'm sure our plummage still doesn't hurt in identifying us though.

    You also have to factor in our fully bipedal stance. The top of our head is where the bulk of the sun's rays hit us, and the rain.
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    Quote Originally Posted by kojax
    You also have to factor in our fully bipedal stance. The top of our head is where the bulk of the sun's rays hit us, and the rain.
    Yup, not suggesting there weren't other factors. Note that we don't have anything like head hair on our shoulders though. As for bipedalism, I totally agree this also sets us apart. Lots of animals stand up as a threat display - homo sapiens threatens even passively.

    ...Time for Pong to name another hypothesis. The idea that hair pattern, bipedalism, and unique vocalizations served also to warn predators and competing species away, called rise up singing.
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    Quote Originally Posted by Pong
    Too much coffee spuriousmonkey, read #2.

    tiny skin hairs = fur.
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  13. #12  
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    Quote Originally Posted by Pong
    Quote Originally Posted by kojax
    You also have to factor in our fully bipedal stance. The top of our head is where the bulk of the sun's rays hit us, and the rain.
    Yup, not suggesting there weren't other factors. Note that we don't have anything like head hair on our shoulders though. As for bipedalism, I totally agree this also sets us apart. Lots of animals stand up as a threat display - homo sapiens threatens even passively.

    ...Time for Pong to name another hypothesis. The idea that hair pattern, bipedalism, and unique vocalizations served also to warn predators and competing species away, called rise up singing.
    Pretty much every animal has a unique look, and a distinct sound, though. You know: a more probable possibility is that it had nothing at all to do with non-human predators, and long hair evolved as a way for humans to identify each other.

    I don't mean they needed it to see that each other were "human", but to distinguish social status. People with greater social status have a higher survival rate, which is exactly the sort of thing that would drive a selection process. The longer your hair is, the more you can style it. The more you style it, the more information others are able to glean from a single look.
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  14. #13 Re: Fur/Hair pattern in humans? 
    Forum Cosmic Wizard spuriousmonkey's Avatar
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    Quote Originally Posted by kojax
    Quote Originally Posted by icewendigo
    We are familiar with animals being furry, but what caused humans to, mostly;
    1- have "long hair" on the heard(when not cut),
    2- no fur on most of the body(tiny skin hairs) and
    I'm thinking clothing for this one. We must have been able to wear clothes for a long time before our minds matured. I'm hard pressed to think of any other naked mammals that aren't nocturnal or something like that.
    Elephants.
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  15. #14 Re: Fur/Hair pattern in humans? 
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    Quote Originally Posted by spuriousmonkey

    Elephants.
    Good example, and Rhinos, both out of Africa. Is that part of why anthropologists theorize humanity might have evolved there too?
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    Apparently, Darwin said in The Descent of Man that beards could have been the byproduct of sexual selection. Facial hair doesn't really present any obvious adaptive advantage, and since females have no beards he figured out it was something else besides natural selection.

    From Wiki:
    Charles Darwin conjectured that the male beard, as well as the relative hairlessness of humans compared to nearly all other mammals, are results of sexual selection. He reasoned that since, compared to males, the bodies of females are more nearly hairless, hairlessness is one of the atypical cases due to its selection by males at a remote prehistoric time, when males had overwhelming selective power, and that it nonetheless affected males due to genetic correlation between the sexes. He also hypothesized that sexual selection could also be what had differentiated between different human races, as he did not believe that natural selection provided a satisfactory answer.
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    Facial hair

    Sexual selection by males doesn't explain men's possessing both smooth skin and very long face hairs.

    Yet neither does sexual selection by females explain facial hair, since when/where females wield considerable selective power, men shave. Note the prevalence of facial hair in established fathers, gay men, sailors, playboys, Greek philosophers, etc. None of these groups invite sexual selection. Shouldn't it be the other way around?





    Head hair

    The near-universal phenomena of men's haircuts demands explanation IMO. Even the dude on Pioneer probe plaques has a haircut... naturally...? Apparently natural long hair is an obsolete encumbrance. "Protection from the elements" does not hold up, because we see - from ancient Egyptian paintings for example - that people very much exposed to the elements were already cutting their hair, as well tribespeople today go around practically naked, hair cut, often without hat or umbrella. It ain't the weather. So both function and obsolescence must be in earlier stages of development. What change made hair obsolete?

    I've suggested the peculiar hair of humans helped identify us as humans, to other species. That's assuming lifestyle comparable to other hominids, wherein we're pestered by competitors that as individuals learn to identify which species aren't worth the hassle. Our useful adaptation becomes useless when we're no longer troubled by predators susceptible to conditioning. In the case of males intent on hunting, and challenging even former predators, appearing characteristically human may even be a disadvantage.

    Long hair in females remains useful today because it helps baby recognize mother. Newborns can't see much, but the one rudimentary pattern they innately fix on is a horizontal pair of large-pupiled eyes. Rapidly they build a sort of prototype face image, including nose and mouth, and soon respond indiscriminately to all faces, even Halloween masks. They won't clearly recognize their mothers' unique facial features from strangers for about two months but they do distinguish between hairstyles. Silhouette, or head periphery, appears easier to babies than inner features. Therefore a population divided by distinct hairstyle is significantly better from the baby's point of view.

    African mothers buck my hypothesis, by wrapping scarves around their heads. African babies have to trust just anybody who picks them up? :?
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  18. #17  
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    Quote Originally Posted by Pong
    Facial hair

    Sexual selection by males doesn't explain men's possessing both smooth skin and very long face hairs.

    Yet neither does sexual selection by females explain facial hair, since when/where females wield considerable selective power, men shave. Note the prevalence of facial hair in established fathers, gay men, sailors, playboys, Greek philosophers, etc. None of these groups invite sexual selection. Shouldn't it be the other way around?
    I wonder if maybe it originally evolved as a Nordic trait for humans living in the arctic regions, who naturally had to wear a lot of clothes all the time. You could identify a male just by looking for a beard. If there's no beard, then what you are seeing is either a female or a prepubescent male.

    Note also that some racial groups don't grow beards. Some people speculate that the legend of the Amazons might have come from Greeks who encountered unbearded men. The word "Amazon" means breastless, and it was believed that Amazon women cut off at least one of their breasts to make themselves more efficient warriors. (Kind of destroys the whole legend if that's true, though, doesn't it? )

    The near-universal phenomena of men's haircuts demands explanation IMO. Even the dude on Pioneer probe plaques has a haircut... naturally...? Apparently natural long hair is an obsolete encumbrance. "Protection from the elements" does not hold up, because we see - from ancient Egyptian paintings for example - that people very much exposed to the elements were already cutting their hair, as well tribespeople today go around practically naked, hair cut, often without hat or umbrella. It ain't the weather. So both function and obsolescence must be in earlier stages of development. What change made hair obsolete?
    I wouldn't say the Egyptians were "very much exposed to the elements". In the northern part of Africa, disease would be quite an issue, and shaving your body hair shows you have good hygiene.

    Come to think of it, that's probably why it has become so prevalent today as well. We're total hygiene freaks. Blame the soap companies for their highly successful ad campaigns that convinced everyone you have to bathe daily instead of weekly or monthly, like people did in the old days.
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  19. #18  
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    Quote Originally Posted by kojax
    Quote Originally Posted by Pong
    Facial hair
    I wonder if maybe it originally evolved as a Nordic trait for humans living in the arctic regions, who naturally had to wear a lot of clothes all the time. You could identify a male just by looking for a beard. If there's no beard, then what you are seeing is either a female or a prepubescent male.
    I like your explanation most. Did we wear clothes long enough for such evolution though? I guess so, and hope some other posters yea or nay the possibility.

    Quote Originally Posted by kojax
    The word "Amazon" means breastless, and it was believed that Amazon women cut off at least one of their breasts to make themselves more efficient warriors.
    Hard core! That's a wicked legend!

    Quote Originally Posted by kojax
    I wouldn't say the Egyptians were "very much exposed to the elements". In the northern part of Africa, disease would be quite an issue, and shaving your body hair shows you have good hygiene.

    Come to think of it, that's probably why it has become so prevalent today as well. We're total hygiene freaks. Blame the soap companies for their highly successful ad campaigns that convinced everyone you have to bathe daily instead of weekly or monthly, like people did in the old days.
    If copious head hair was a disadvantage then, why wasn't it before? See, something's missing.
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  20. #19  
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    Quote Originally Posted by Pong

    Quote Originally Posted by kojax
    I wouldn't say the Egyptians were "very much exposed to the elements". In the northern part of Africa, disease would be quite an issue, and shaving your body hair shows you have good hygiene.

    Come to think of it, that's probably why it has become so prevalent today as well. We're total hygiene freaks. Blame the soap companies for their highly successful ad campaigns that convinced everyone you have to bathe daily instead of weekly or monthly, like people did in the old days.
    If copious head hair was a disadvantage then, why wasn't it before? See, something's missing.
    How would you tell good hygiene from bad if there were no hair to remove in the first place? I kind of like the compromise that a lot of people struck in the 1800's, of just cutting off most of their facial hair, but keeping the mustache or goatee.
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    Are you suggesting we evolved a liability just to prove we could remove it with technology? In this case those who lack the technology or socialization die out...?

    Counterintuitive, but damn amazing if true.
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    However, men don't start growing facial hair until they hit puberty. At puberty men start producing testosterone, and testosterone means sex. So the presence of testosterone is related to the development of facial hair. so, when our female ancestors were selecting a mate, it could be possible that they selected based on the amount of facial hair because it was related to how reproductive they were. a female would not mate with someone that had little facial hair because it would be a sign that he was not of reproductive age.

    I am pretty sure that thick hair prevents microbial infection, which is why it is present in the pubic areas.

    Also, doesn't the thick hair on our heads serve as a protective mechanism? As a species, our heads were the most vital part of our bodies, so a little extra padding would be good to have
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    I tent to think that some form of human selection(sexual, tribal, cultural) is more plausible than most adaptative explanations. I think female humans have breasts(more developped compared to several species of mammals) because male humans associate this visble trait with femaleness, I wonder if this sexual differentiation occured after we no longer had much visible body hair since a small difference is breast size might be easier to notice if theres not a lot of fur.

    The beard is easier to explain, its like a male lion's mane, but lions dont have a pubic hair mane but just the same fur as everywhere else as far as I know.
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    I think it may be true that hair/beards etc are a result of sexual selection but as dlambert said, I think the original push for this selection could be that hair in all the right places indicates testosterone production, so I would say that (like we are "preprogrammed" to think babies are cute, so we are instinctually more likely to take care of them) it could be a form of psychological push for sexual selection, to create a horribly mish-mashy new term.
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    I think it's hard to imagine, but society itself is an ecosystem, and an environment. Beards could have evolved as a way for two tribes to differentiate between each other. Sort of a "shirts and skins" type of arbitrary difference that makes it easier to tell which team you're on. Whoever exemplified the trait more would tend to be elevated in social status within their own tribe, and women flock to the guy who can give them a higher social status in the group.

    Here's a fine example of what I mean, but in reference to a different trait:

    http://www3.cesa10.k12.wi.us/ecosyst...ad/flathed.htm

    Some indigenous American tribes would deliberately bind infants' heads to make them take a pointed shape. (The "flat heads" were actually called that because they didn't do this.) You can well imagine how that might create selective pressure toward heads that handle being distorted better than others. And as near as I can tell, the whole reason for head binding would be just to create an identity.
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    Try to bear in mind we developed these traits immersed among other species, which also reacted to our appearance. It is easy now to forget and think our appearance just for human eyes.

    Plainly we evolved to look different than our chimp brothers. For thought experiment, suppose the branch from chimps had not been human, rather it had been a roughly generic-looking hominid wielding a terrible unseen sting, that predators had best learn to avoid. Wouldn't it be advantageous for this stinging hominid to develop clear markings so others could easily identify it and keep their distance?

    And of course the chimps wouldn't copy the markings because then they'd be getting stung by mistaking foe for friend.

    We did have stingers: pick up a stick & crack it down hard, huck a rock bang on the nose!
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    Well, you know: we also had technology for that. A lot of ancient cultures painted their bodies, and clothing has always been at least a little bit decorative. Maybe longer hair is more useful for decorations?


    I'm still going with the body cooling hypothesis right now, though. Our brains consume large amounts of energy, and so we have to keep them cool. Having long strands of hair makes it easier to conduct heat away from your body. Your sweat evaporates faster, because it has more surface area when it's dripping down a strand of hair, which makes room for you to generate more of it. But, even more importantly, the faster it evaporates, the faster the heat energy it contains disperses into the air.

    It seems counter-intuitive, but I'm pretty sure that hair on a human body is more for cooling than heating. That's part of why you grow it in the pubic regions, which actually need to be maintained a couple degrees cooler than the rest of your body, not warmer.
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    Quote Originally Posted by kojax
    It seems counter-intuitive, but I'm pretty sure that hair on a human body is more for cooling than heating.
    That insulation works for hot and cold. Likewise one needn't "go with" one particular explanation of any trait. So, I've offered one explanation for human hair pattern, that does not discount parallel explanations.
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    Quote Originally Posted by Pong
    Try to bear in mind we developed these traits immersed among other species, which also reacted to our appearance. It is easy now to forget and think our appearance just for human eyes.

    Plainly we evolved to look different than our chimp brothers. For thought experiment, suppose the branch from chimps had not been human, rather it had been a roughly generic-looking hominid wielding a terrible unseen sting, that predators had best learn to avoid. Wouldn't it be advantageous for this stinging hominid to develop clear markings so others could easily identify it and keep their distance?

    And of course the chimps wouldn't copy the markings because then they'd be getting stung by mistaking foe for friend.

    We did have stingers: pick up a stick & crack it down hard, huck a rock bang on the nose!
    It's known that a lot of other animals do have markings. I'm not sure how successful this pattern has been in the evolution of such creatures. You could try looking up poisonous frogs and such, creatures that have no defense while they're alive, but they'll poison you if you eat them. A lot of poisonous snakes have distinctive patterns. A rattle snake's rattle is certainly not there to increase its stealth abilities.

    The major problem I see with this is that a predator's reaction would have to evolve after the trait already existed. Either that, or the trait would have to evolve as a response to a predator's instinct that already existed. (But this becomes complicated if there are multiple predators.) It's hard for me to see how the two would have evolved at the same time, concurrently.

    It's important to remember that most animal types don't communicate abstract ideas to each other very well, or educate their young more than just a very basic level. It's not like the lions are going to be talking to each other and saying "Dude, look out those monkeys with long hair. They've got spears." It's more like a kind of natural selection will select out lions that don't know any better, until all that remains are lions with an unexplicable phobia against long haired apes.
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    You forgot that our main enemies and competitors learn in their lifetimes. Look, I'll prove it to you: I'll go to one of these baboon sanctuaries, presenting as a typically clothed modern human, and I'll terrorize any baboons that annoy me. I'll shout at them, pelt them with sticks, that kinda thing. Well no I won't because I'd be arrested. Why? Because everybody just knows such behaviour will make those baboons flee at the sight of humans, spoiling tourism.

    Baboon "Gangs" Run Wild in Suburban South Africa

    Instinctive species-specific fear by natural selection isn't necessary. Animals learn. Like I said in another thread: scarecrows work best when all the farmers throw stones at crows.

    Did you know that bear intrusions into BC suburbs are becoming bolder? A few times the (carnivorous) black bears have gone so far as to start eating people. The problem is that modern humans aren't teaching bear to stay away. The bear just keep coming back, bolder and bolder each time 'cause all humans do is watch in silence as the bear topple garbage cans and so forth. Meanwhile rural folk know you've got to scare the bears off, however possible, lest the bear learn that humans are no bother.
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    Quote Originally Posted by Pong
    You forgot that our main enemies and competitors learn in their lifetimes. Look, I'll prove it to you: I'll go to one of these baboon sanctuaries, presenting as a typically clothed modern human, and I'll terrorize any baboons that annoy me. I'll shout at them, pelt them with sticks, that kinda thing. Well no I won't because I'd be arrested. Why? Because everybody just knows such behaviour will make those baboons flee at the sight of humans, spoiling tourism.
    So your theory is that having a unique identification allowed humans to educate the local predators?

    What I was getting at about purely genetic learning is that only a predator that has had some contact with humans during its lifetime will know what's so special about us, unless the programming actually evolves into their genes. They can't talk to each other as such. They can kind of communicate emotions, though, so maybe if one black bear sees another black bear start to get really uneasy around a certain scent, or in the vecinity of a certain settlement, I guess that would work. Children would see their parent get like that.

    The humans must have had the common sense not to always kill predators. If, instead of scaring black bears off, we simply shot them, I'm guessing there wouldn't be a lot of communication happening.
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    Quote Originally Posted by kojax
    So your theory is that having a unique identification allowed humans to educate the local predators?
    In addition to other debatable advantages, yes.
    A pong by any other name is still a pong. -williampinn
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  33. #32  
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    [quote="kojax"]
    I'm still going with the body cooling hypothesis right now, though. Our brains consume large amounts of energy, and so we have to keep them cool. Having long strands of hair makes it easier to conduct heat away from your body. Your sweat evaporates faster, because it has more surface area when it's dripping down a strand of hair, which makes room for you to generate more of it. But, even more importantly, the faster it evaporates, the faster the heat energy it contains disperses into the air.
    quote]

    I would watch that statement. While that would explain the function of the hair on the top of our heads, it does not explain facial hair. By your explaination, hair is used to evaporate some of the heat generated from our brains, which I completely agree with. But your hypothesis fails to explain why men have facial hair and women do not. Men and women equally use their brains- so why don't women have facial hair?
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