Why are humans relatively hairless as a species?

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I think the reason is fairly obvious... its because we wear clothes

It could be because, unlike other animals, we dress ourselves for warmth and so hair isn't needed so much now to keep our body temperature within the optimum range. Without clothes, the hairy folk would be more likely to survive and pass on their genes.

But why would we start wearing clothes while still having hair covering our bodies? It is far more likely that we started wearing clothes because we started losing our hair.

Reply 21

Amphiprion

Original post by ApeMob

There is science behind it, if you know then feel free to enlighten me otherwise I know what I know and hair covers parts for protection that the rest of the body doesn't need, as it does need sun and oxygen and moisture that other parts easily infected don't need. :closedeyes:

Those parts are naturally covered in the most hair. &As humans evolve I'm sure so will our needs and we will probably look diff as time goes by anyhow.

About 6 million years ago our ancestors were about as hairy as other apes (chimps, gorillas etc), then a genetic mutation in our ancestors DNA led to less hair or possibly almost complete hairlessness evolving, probably quite rapidly.

To be honest I'm a bit too tired to go into depth about it all in person, I will say that we do not know for sure why or how it happened but there are large feasability issues with most prominent hypotheses. What we do know is that we share a common ancester with chimps, orangutans, gorillas etc. They have all continued to be hairy and posess genes encoding a hairy phenotype, we do not. That makes it overwhelmingly likely that we lost it rather than they all developed it and we did not.

Here is one published scientific theory on it, a lot of information is in there if you want to read about it cause I cant be botherd to summarise it haha.

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2443.2012.01592.x/full

500px-Ape_skeletons.png47.4KB

Reply 22

VladThe1mpaler

Original post by Juichiro

If that was true, I would expect to see some other top predators also hairless but thing is none of them have our low level of hairlessness. So I don't think the boldened bit is true.

It's down to natural selection which is completely random. Just because one animal gains a trait which is valuable doesn't mean another will also develop it.

Reply 23

Another

Original post by Juichiro

If that was true, I would expect to see some other top predators also hairless but thing is none of them have our low level of hairlessness. So I don't think the boldened bit is true.

It's worth noting that most other predators don't do endurance at all when chasing prey. They either rely on speed or suprise attacks, they don't run the prey animal down until it wears out (and if they tried, they'd probably fail)

Reply 24

TroyAndAbed

I think I am the missing link between man & monkey. :frown:

Reply 25

Kåte

Original post by VladThe1mpaler

But why would we start wearing clothes while still having hair covering our bodies? It is far more likely that we started wearing clothes because we started losing our hair.

We didn't start wearing clothes just for warmth though. Even with hair, you'd still need protection from various parts of the environment.

Reply 26

Juichiro

Original post by VladThe1mpaler

It's down to natural selection which is completely random. Just because one animal gains a trait which is valuable doesn't mean another will also develop it.

Good point.

Reply 27

Rakas21

I believe I read that we are the sweatiest animals on the planet and that because we originated in a hot climate, sweat allowed us to cool down faster because hair has been proven to better hold heat.

Thermoregulation basically.

Reply 28

Jooooshy

Original post by anonymouspie227

I think the reason is fairly obvious... its because we wear clothes

I laughed

10/10

Reply 29

Juichiro

Original post by Another

Good point. But surely, once endurance was not critical to survival we could have expected to see more variable levels of hairiness. Instead, we still see very uniform levels of hairiness in gaussian distribution fashion. I think endurance has nothing to do with it.

Perhaps a simple analogy is that of myopia and similar eye conditions. Back in the days, the lack of an eye condition was likely to be critical to your survival (and reproduction) so you wouldn't expect many people with this condition make it to their eldery ages. It was a "bad" trait to have. But nowadays, since glasses are available, having or not having an eye condition is not likely to affect your survival (and reproduction). And thus, we would expect to see a relatively larger amount of elderly people with eye conditions developed in their youth. My point is now that eye conditions are not discriminated (in favour or against), they might become more common.

Similarly, since endurance is now not discriminated (in favour or against), we should expect endurance and hairiness become common. While levels of endurance has deffo become more variable (see tribal warrior vs Western citizen), levels of hairiness are still pretty much uniform across the world. I would say that just like Mad Vlad said to me, that evolution contains some randomness so perhaps the hairlessness gene randomly got on our train and became popular for some reason.

Reply 30

ihavemooedtoday

The theory I heard is that humans kill other animals for their fur, so we don't have to grow hair ourselves, which is high maintenance and have parasite issues. I am not sure if the timeline matches up, though (when humans started using sharp tools to be able to skin animals vs when they lost hair).

I guess it could be similar to how some animals use other animals' shells, or steal their nests, etc.

Reply 31

nexttime

Original post by Juichiro

Reply 32

ihavemooedtoday

Original post by nexttime

Endurance has been non-critical for all of, what, 200 years? Before that we were all still manual farmers. Evolution does not act that quickly.

We see more myopia because of reduced infant mortality and because people live longer. Great eyesight has probably been less critical for a longer time, but still not an evolutionarily significant period of time.

Westerners would still be good at endurance if we had manual lives. We're bad at endurance because McDonalds.

And for what its worth, there are some differences in hairiness. Africans have very different hair to westerners, and south Asians tend to be hairier generally. Not sure if that is significant.

There are also strong indications that myopia is caused by reading (eyes focusing close) at young ages. That is also a very recent thing, evolutionarily speaking.

Myopia could be something like susceptibility to heart diseases from high fat diet - humans haven't had that much fat to eat for long enough for that to be a ******* evolution can act on.

Reply 33

Puddles the Monkey

Original post by Juichiro

If that was true, I would expect to see some other top predators also hairless but thing is none of them have our low level of hairlessness. So I don't think the boldened bit is true.

Humans hunt by endurance - we chase down prey over long distances, which is partly why we're so terrifying; you can't get away. Other predators don't really hunt in that way, which is why they don't need to be able to sweat I think.

:dontknow: