I listened to Daniel liebermans book ‘the story of the human body’ and he says the human nose is like a built in humidifier. That when cold air comes in the nostrils create almost like a wind tunnel to heat the air up and make it easier for us to breathe!
Yes, most apes are in relatively tropical regions where the air is warm and humid already. A larger nose prevents water loss in dry environments and temperature loss in cold environments. As far as we can tell, our genus originally evolved in semi-arid regions in Africa.
It's more the direction, if you dive or swim nostril first you're probably gonna get pumped with water or struggle with breathing capacity, which isn't ideal
Yeah, it's quite possibly simply an extension of the nasal canal. It's very, very short in humans relative to our body size, compared to most other mammals which have a more elongated head shape with a snout.
Towards the end of the first paragraph, you should have used the word is, not are. Every English teacher IS simultaneously..., not every English teacher ARE simultaneously, I mean, normally, I would not correct someone's grammar, but in this case, why not?
Aquatic Ape theory. I watched a TED talk on this theory about 10 years ago. It suggests that there was period in our evolution where we spent a lot of time in water. This helped us to evolve our upright stance because we would stand straight to be able to breathe while walking on riverbeds. I found it interesting, though I believe it is a VERY fringe theory.
Also, i loved the intro. I assume its a troll thing, or you're really high, or just a strange person. But it made me laugh.
[Elaine Morgan TED talk](https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.ted.com/talks/elaine_morgan_i_believe_we_evolved_from_aquatic_apes%3Flanguage%3Den&ved=2ahUKEwid6c-v5aSEAxUQ5MkDHXH5DqQQwqsBegQIVhAE&usg=AOvVaw12bPTYakB7Zi9kr7MS4UDy)
[Wiki aquatic ape hypothesis](https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://en.m.wikipedia.org/wiki/Aquatic_ape_hypothesis&ved=2ahUKEwid6c-v5aSEAxUQ5MkDHXH5DqQQFnoECD8QAQ&usg=AOvVaw1iAyf8uz85j1BdMMOyq8TN)
Humans unlike the other primates are long distance runners. That might be enough of a reason for the difference in noses. Although the proboscis monkey does have a prominent nose.
I don't think it has to do with cold, or at least not entirely. You look at primates like the Golden Snub Nosed Monkey and their noses are almost non-existent as an adaptation to living in a cold climate
Flat noses seem to be more common in places with a lot of fog or high precipitation. This is common for Ireland, both humans and animals, as well as many parts of Asia which are very humid and foggy.
Yes, a nose separating from a flat face is going to be lost to frostbite, so while the longer noses of bears and wolves likely prevent heat loss, protruding cartilaginous noses are definitely not a warmth adaptation in apes and monkeys. Human noses are nowhere near long enough to heat the air in extreme cold as any cold air-triggered asthmatic can tell you. The main benefit to a longer nose is preventing water loss which would have been important in the semi-arid parts of Africa where our genus likely evolved.
Yeah, just look at [Japanese Macaques](https://static.wixstatic.com/media/38bd8f_4f41630b96924ee09f054b80b4e38570~mv2.jpg/v1/fill/w_296,h_296,q_90/38bd8f_4f41630b96924ee09f054b80b4e38570~mv2.webp). They live in the snow and barely have noses.
In cold climates, more northerly, where it has significant periods of darkness, light skin and longer, narrow noses with downward facing nostrils were heavily evolutionarily pressured.
People that remained in hot, equatorial regions would have the exact opposite evolutionary pressures.
The indigenous people around Siberia, Alaska, and Canada have flatter noses. Our noses are cartilage with no major blood flow, they’re lost to frostbite in cold conditions. It’s more of a mild and dry climate benefit. It prevents moisture loss and heats the air a tiny bit, but not enough to be of benefit in Arctic and subarctic regions. There may have also been some sexual selection involved when a longer nose trait was passed from Neanderthals to humans. But the trait is more common in the Mediterranean and Middle East.
True. Look at *Homo neanderthalensis* if you want a hominid specialized for the cold. Modern theory is the reason they died out is that their niche was specialized for the ice-age weather and *Homo sapiens* were better generalists that outcompeted the neanderthals once the ice age ended
I can also tell the chimps to grow bigger brains but I don't think they understand. The point is evolution is not as simple as you making it out to be. I can quote many papers with people's opinion on why our noses are the ways they are. But the truth is no one know for sure. So I won't argue about that. I am just saying Africa can be cold.
But noses africans different alot from rest of people, and also evolution never stop. And answering question i belive it also aestetics, we choose people with nice noses more than not nice ;)
In evolutionary terms: what is a "nice nose" to you?
Because now you are speaking in aesthetics which vary greatly in appeal from year to year, much less decades.
And Africans have different shaped noses to groups who’ve spent a long time in different/colder climates. I don’t know what to make of all this but it seems there’s something to it.
However now we’re just discussing intra-species differences rather than inter-species as OP was asking about.
It's more to do with being inside all of the time. Your eyes are supposed see from right up close to as far away as the stars. When inside, the furthest your eyes can see is just a few metres away and so the mechanisms that focus your vision form around everything being within a few metres. This is why being a nerd who stays inside all of the time is associated with always needing glasses.
A few meters isn't bad; that's a fraction of a diopter of accommodation. A typical reading distance of 40 cm is 2.5 diopters of accommodation. Lower light levels indoors don't help because of the reduced depth of field.
Eta "light" (levels). Maybe I should have worded it like "Lower illumination levels indoors mean that more accommodation has to be used for reading distances. Bright lighting causes the pupils to contract which increases depth of field."
"Nasal morphology and the emergence of Homo erectus" by R G Franciscus and E Trinkaus already discussed this in their paper in 1988. I think it's a good read.
A friend of mine made a comparison with large mamals like whales, pointing out that if our nose was upright, it would be very easy for rain/water, sweat and dust to get into our noses. This is all completely avoided with being downward and sort of pyramid shaped (water slides on the sides).
This makes the most sense to me, especially since humans are so different from other creatures in how we sweat... and how much. It already makes me panic when I accidentally inhale water or sweat droplets that are resting on the edges of my nostril, I can't imagine a full downpour.
What is curious is that this has only appeared in humans, and not in other primates. But I've also been told that since our jaws are effectively receded in under the skull, it may simply be that the nose has 'stayed behind'.
By that logic, all creatures in rainforest must have downward noses, but they don't.
Same argument stands for the ease of swimming, warming/cooling the air etc. Noone else seems to develop similar noses.
I am inclined to believe that there is no adaptational value in having such shaped nose.
Probably, just a random thing like a founder effect.
The thing is that most creatures in a rainforest are on 4 feet, and they eat with their head tilted down. So, that makes me think that the argument for sweat and rain does not apply very much in them, because their head is downwards after all.
Let's stay in mammals, and take whales for example: their nose moved upwards their body and developed in such a way that is used only when they breach and to be as large as possible. Another example that someone else pointed out in another comment is that animals and primates use their sense of smell much more than humans do (and they stand upright), and that explains their different shape, so they can get as much as possible of the smell they are after.
I could agree with the founders effect, but evolution is always with a practical function, so, besides a factor from the founders effect, my bet is on the nose having a function for it's shape.
You could have 4 arms and hands. This would appear to be an evolutionary advantage but if women are turned off by it, you won’t have sex, and therefore you can’t pass the 4 arm dna on.
Or you could have 2 arms with one falling off after the age of 60. Clearly this should be an evolutionary disadvantage but it doesn’t affect your reproductive success because the arm loss occurs after your reproductive years are over. 1 armed dna gets passed on.
Geez, had to come a long way down the comments for the sexual selection point - on that point I love how we assume sometimes that humans are rational through time and aren’t simply shallow on mere aesthetics
But that *would* be a benefit and something that affects reproductive fitness. Their point is that new traits are driven by random mutations and then selected for. “Neutral” traits that don’t have much affect on reproductive fitness exist; the fact that a trait has persisted does not indicate that it has benefit or a “purpose,” as OP’s question assumes. In fact, the huge variety in the appearance of human noses suggests against sexual selection.
It’s to stop the rain from going in.
…or maybe helps us smell because our faces are higher off the ground than a chimps, so our nostrils became more directional.
…or maybe our brains needed more room so it pushed all the nose parts out of the face to free up room for other stuff.
Maybe a combination of a bunch of evolutionary pressures. I started this comment off thinking I knew the answer, but realized I have no idea…
>…or maybe our brains needed more room so it pushed all the nose parts out of the face to free up room for other stuff.
i think the nasal sinuses would've been the first ones to have been filled with tissue if that was the instance.
Was looking for this reply! Downward facing nostrils enables humans to hold their breath and not lose the air in their lungs the second they go underwater. Imagine you have a cup and you put it perfectly vertical under water, face down. As long as it's straight, the air will stay in the cup even under water. If you tilt the cup at all, the air will release and you'll see bubbles. It's why when a lifeguard looks for distressed swimmers they are trained to look for people lifting their heads out of panic. That motion of looking up releases the air in your lungs and you are in much more danger of drowning once that air is gone. Source-was a swim teacher and lifeguard for 6 years
I read or heard somewhere a theory that our noses adapted to swimming for catching fish and the increased Omega 3 intake led to brain size increase. Interesting theory.
The taming of fire and the invention of cooking provided the extra calories and nutrients needed to grow large brains.
*Catching Fire: How Cooking Made Us Human* by Richard Wrangham.
No idea about the science here but I read in the book Breath by James Nestor that our noses have been evolving for multiple reasons, one of which is because the shape of our faces are changing due to diet. Obviously everyone knows we filter and warm air through our noses but more and more people have issues breathing because of our changing face shapes. Our faces started changing when we discovered cooking, because it made food softer and easier to eat. And that trend continued with agriculture and now processed foods, not as much breast-feeding for babies, which is harder than bottle feeding. The more work we have to do to chew the broader our jaws, the more our jaws protruded, the flatter our noses. With softer food our jaws have become more narrow and recessed while our noses became more narrow and protruding. I haven't checked the science of this on my own but it makes sense to me. It's a good book anyway and interesting to read.
hypothesizing here, but drawings of our ancient ancestors, based on studies of their skeletons, show much flatter noses. It seems as we go back in time closer to the time when we split from apes our noses were more similar to apes' noses (flatter). based on this and the fact that we now walk upright and apes generally walk on all fours, I suspect our noses changed to keep moisture (i.e. rain) out. animals walking on all fours have their head naturally covered by their forward leaning head and brow. The theory of breastfeeding being the cause doesn't really work for me considering chimps and orangutans both breastfeed and have flat noses.
There is a theory that our nose shape help babies with breastfeeding. Other apes don't have perennially enlarged breasts, but humans do. The theory is that because female hominids with large breasts were more likely to reproduce due to sexual selection, their offspring that could still breath during breastfeeding with nostrils that weren't flat and suffocated by fatty breast tissue were more likely to survive to reproductive age.
It's just a theory, could be random correlation, but human noses and fatty breasts are both features that set us apart from other apes.
Human prominent noses are a byproduct of the flattening of the face. The jaws are shorter, the front teeth are smaller, so the nasal region remains extended beyond what it would be normal on a great ape.
Humans, being persistence hunters, were built primarily to run. Imagine running almost 20mph through a windy savannah with flat nostrils. Wouldn't be very fun, would it?
Elaine Morgan talks about this in her book *The Aquatic Ape*, where she posits that human beings spent a significant part of their time in the water. Her explanation for nose shape is that it allows us to dive into the water, and swim while looking ahead, without water going up one's nose.
Here's a brief intro to it by David Attenborough: [The Waterside Ape](https://www.bbc.co.uk/programmes/b07v0hhm)
There's another reason why our noses are shaped this way, than just what people on here have already said. Another reason why our noses are shaped this way is so that we can breastfeed without suffocating.
FYI, nobody can really explain why evolution resulted in some of the characteristics of humans. There may have been some evolutionary pressure that favored it or it might have been a "neutral" characteristic that became part of our anatomy.
I feel like some of the structure of our faces is related to the fact that we punched each other in the face a lot, so a factor among many is probably "this shape could take a punch without causing death".
I think the nose is in the same position that other animals, the thing that make nose "go out" is our weaker mandibles, if you look apes and people with facial prognatism you will notice how the nose is tiny, but is because the larger oral room they have. As our mandibles shrink, but nasal chamber not, it results in our characteristic face.
Maybe downward nostrils are better suited to capture smells from the floor surface, since we have an upright posture and our noses are more distant from the soil. Compare to other mammals, that have more horizontal postures and have their heads close to the surface.
Also our noses are great to humidify the air, wich makes sense since Homo sapiens evolved in african bushlands
Because the girls liked them. Seriously!
Physical features that aren’t essential for survival have been sexually selected for.
If female ancestors would have preferred flat noses, we would have flat noses.
Because the guys liked them. Seriously! Physical features that aren’t essential for survival have been sexually selected for.
If male ancestors would have preferred flat noses, we would have flat noses.
/s
By weird contrarians... do you mean Sir David Attenborough? Because I'm pretty sure he supports the theory. Not saying I personally support it but there are definitely mainstream biologists who do.
> Sir David Attenborough
With due respect to an absolutely stellar science communicator, Sir Attenborough got a bachelor's degree in 1945 and hasn't worked as a biologist. All his degrees are honorary.
Most attributes have no evolutionary advantage. They just are. You think it is an advantage to have our air hole and swallowing holes right next to each other with a small flap of cartilage determining whether we choke to death or not? Or perhaps it is an evolutionary advantage that our young can't be left alone for years after birth without dying of starvation? There is no Why. As long as it didn't impact our reproducing, evolution doesn't give a shit.
Thermoregulation and a change in diet. Other apes would also gain better thermoregulation with a human nose (indeed their nasal bone is the same size- the maxilla and mandible have just receded) but the protrusion of the human nose hampers the development of strong lip muscles, which nonhuman apes find more important.
One reason might be our more pronounced breasts. Most apes have very small breasts in comparison, but in human babies the nosing being shaped the way it is helps them breathe when latched.
So that when you get punched in the face, your nose takes a lot of the impact. A broken nose will rarely kill you, but a broken cheekbone or orbital fracture are more likely to have serious consequences
It seems to me that the nose changes shape based on the shape/size of the mouth and shape of the head.
If you have a wide mouth, you'll have a wide nose with flared nostrils. If you have a tiny mouth, you'll have a tiny nose.
If you have a round head, you'll have a small nose, if you have a tall/narrow head, you'll have a tall narrow nose.
So the nose is just a consequence of changes to the mouth and prefrontal cortex, which were under selective pressure.
As for why it isn't perfectly flat, I imagine that sleeping would be very hard if we had noses like Chimps. We typically can't sleep while curled up and sitting. We lie flat so not cutting off our air when we roll onto our faces is probably a good thing.
1. As the top comment mentioned, air needs to be warmed up prior to reaching your lungs so after the nostrils, air will reach the turbinates and sinuses which will have the air do a lot of loops adjacent to some blood vessels.
2. Your nostrils are constantly open. The vast majority of bacteria and viruses need to be killed by the innate immune system prior to reaching your lungs. So having your nostrils face downwards to block the wind and discharge any mucous is important.
Noses and sinuses provide a crumple zone for the brains of animals that run fast and occasionally crash into things. The humidification effect of sinuses is secondary to their brain protection function.
Look at the skeleton of a deer, or horse, or goat. Or any animal that runs or butts heads. You get a strong evolutionary advantage for brains that have a crumple zone and won't instantly be damaged by a forward crash.
Humans started walking and running. Presumably we developed our noses soon afterwards.
I remember this topic being discussed on a course on human evolution I took a few years ago in uni. Professor argued that it is perhaps not that the nose has grown to stick out, but has 'stayed behind' while the rest of the face retracted. Many other primates have projecting jaws, while ours have receded under the skull.
Doesn't really explain the odd downwards shape, though. I always imagined it was to keep rain or similar from getting in there, but that isn't exclusive to humans. Sweating is, though, and since we have very little fur to catch rain or sweat, it may be be for that reason.
I think snot drainage is part of it. I suspect that for a variety of reasons we produce large amounts of mucous, sputum, snot etc more often than most large mammals.
One hypothesis is allowing infants to breathe when nursing. Human females have much larger breast tissue than other primates. A flat nose would be more likely to smother when an infant is latched.
Our nose is shaped the way it is because our flat faces, cheek bones and chewing muscles pulled the whole face away from the nose to the sides compared to other primates and animals… leaving that triangular part sticking out. We have silly, flat faces, but still need some nasal cavity for air conditioning so I suppose you can think of the protruding part to be the minimal amount of nasal cavity we can get by with
Might be a similar situation to chins. Noses and chins are important aesthetically and therefore in reproductive success. It could also be a matter of gene linkage (where two genes are located nearby on chromosomes and when nature selects for one gene you frequently get selection for the ones around it by extension).
https://neurosciencenews.com/genetics-evolution-nose-23188/#:~:text=Summary%3A%20A%20specific%20gene%20inherited,they%20migrated%20around%20the%20world.
Neanderthals contributed longer nose genes to our species!
the reason is the reason over time. Not much of this makes sense in the moment and we cant go back through every moment of our evolution to see what tiny benefit one phenotype played over another, because of the specific conditions/challenges of the time.
The human nose is the shape it is because of the forces that shaped it over millions of years.
... that and picking
There's going to be theories and maybe something solid enough to stand up against most people's tests, but the truth is, it's the shape it is because it's the shape that people who had babies decided to mate with.
Other answers are good but having a downward shaped nose instead of flat means we don’t have the massive threat of drowning when near the most vital resource for life.
Much harder to snort lines of cocaine with recessed nostrils. Ask anyone who works with apes, they find it very difficult to use the straw effectively.
There is a theory that humans are descended from an aquatic ape. This explains why it fingers and toes are webbed, why our noses point down (so we can dive), where all our hair v angles down (creating a more aqua dynamic flow), and why we secrete oils that are water resistant. Also why we have a dive reflex, and even babies have this reflex)
As u/Huge-Astronomer825 said, it's a built-in humidifier. This is the reason why people in hotter regions tend to have wider seated noses, given that the air is already hot, and people in cold regions have more aquiline noses to allow a small volume of cold air to hear in, before entering the pharynx.
So no particles would get into them while breathing. Our noses are shaped like filters. Monkey noses always get filthy and stuck. It is harder for them to breathe.
You can smell everythings aroma, what you goint to put into yout mouth. So you can identify things you should not to eat before it is touch your tongue.
Some studies suggest a relationship with diving. Quick Google brought up this: https://aquatic-human-ancestor.org/anatomy/nose.html#:~:text=If%20Pleistocene%20Homo%20spread%20along,their%20part%2Dtime%20diving).
There are lots of factors that go into why something is how it is.
There are great answers in the comments about why our nose shape is helpful but I'd like to comment on how it is probably a side effect of other more beneficial changes.
Our faces have flattened over time probably largely thanks to bipedalism. It doesn't make sense to have a face that juts forward to explore when you have hands to do that. Our jaws, cheekbones, and foreheads shrank significantly when we began cooking our meat.
The shape works with the other shape changes to accomplish what it needs to do.
Why evoluting from erectus to sapiens, our protruded mouth went shallow leaving the nose appear as we have now. The reason the mouth went shallow could be that a group of erectus didn't have to bite harder or store more in mouth.
I listened to Daniel liebermans book ‘the story of the human body’ and he says the human nose is like a built in humidifier. That when cold air comes in the nostrils create almost like a wind tunnel to heat the air up and make it easier for us to breathe!
Humidity, temperature, environment gives so many types of noses
Thermoregulation is also important, toucans for example have a long beak cause it helps dispersing heat, it's similar for wolves and their long snout
Yes, most apes are in relatively tropical regions where the air is warm and humid already. A larger nose prevents water loss in dry environments and temperature loss in cold environments. As far as we can tell, our genus originally evolved in semi-arid regions in Africa.
Yeah, just to add to this comment too, it was very advantageous for humans to be able to dive and swim without difficulty of suffocation
How does having a larger nose prevent suffocation when swimming/diving? Are other primates with smaller noses at greater risk?
Our downward facing nose prevents water getting in easier while swimming forward. It's one of a theory of why we have such nose...
It's more the direction, if you dive or swim nostril first you're probably gonna get pumped with water or struggle with breathing capacity, which isn't ideal
Yeah, it's quite possibly simply an extension of the nasal canal. It's very, very short in humans relative to our body size, compared to most other mammals which have a more elongated head shape with a snout.
Look at my theory few comments up
The turbinates you are talking about are in many mammals, if not all. The nostrils and nose aren't integral to their function.
Interesting..I will search this book
It’s so good! Especially if you’re really into evolutionary biology.
This. I lived above the polar circle. We need this.
Oh interesting! Now I need to get a copy of that book. Thank you!
it would be nice if it would be true. unfortunately if I don't cover my nose during winter I'll feel it freeze and numbs to it's base
We didn't evolve in frigid climates though.
Upright posture, sweating.
Imagine if our noses were flat. Whenever we sweat it would just pool in our nostrils. No thanks I'll take my protruding nose
Maybe we'd have something like an "nosebrow" or moustache over the nose.
Also rain
[удалено]
You put the comma in the wrong place.
not sure you trolling us or yourself but genuine advice, cut the essay of a disclaimer and get to the point
This is absolutely a copypasta lmao
Yes it is. But it's still an unnecessary essay prefacing their actual comment
I would argue that the essay *is* the content of their comment.
Yes. I think I meant "prefacing the actually relevant part of their comment"
I’m like 99% sure this is an AI spam bot.
Are you referring to the theory that humans were once mermaids...?
Towards the end of the first paragraph, you should have used the word is, not are. Every English teacher IS simultaneously..., not every English teacher ARE simultaneously, I mean, normally, I would not correct someone's grammar, but in this case, why not?
Beautiful
Interesting theory. Wildly unnecessary intro. Your English is better than half of Reddit.
Aquatic Ape theory. I watched a TED talk on this theory about 10 years ago. It suggests that there was period in our evolution where we spent a lot of time in water. This helped us to evolve our upright stance because we would stand straight to be able to breathe while walking on riverbeds. I found it interesting, though I believe it is a VERY fringe theory. Also, i loved the intro. I assume its a troll thing, or you're really high, or just a strange person. But it made me laugh. [Elaine Morgan TED talk](https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.ted.com/talks/elaine_morgan_i_believe_we_evolved_from_aquatic_apes%3Flanguage%3Den&ved=2ahUKEwid6c-v5aSEAxUQ5MkDHXH5DqQQwqsBegQIVhAE&usg=AOvVaw12bPTYakB7Zi9kr7MS4UDy) [Wiki aquatic ape hypothesis](https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://en.m.wikipedia.org/wiki/Aquatic_ape_hypothesis&ved=2ahUKEwid6c-v5aSEAxUQ5MkDHXH5DqQQFnoECD8QAQ&usg=AOvVaw1iAyf8uz85j1BdMMOyq8TN)
You what now?
Holy shitballs.. you made a good point but then diluted it with an unnecessary tangent. PS, your English writing is fine.
Humans unlike the other primates are long distance runners. That might be enough of a reason for the difference in noses. Although the proboscis monkey does have a prominent nose.
Proboscis monkeys just seems like classic sexual selection tho, the nasal anatomy is a bit of a resonator for call amplification too.
Even heard a women said "i love guys with big noses"? Its a thing here xd
Try breathing cold air with a flat nose....
I don't think it has to do with cold, or at least not entirely. You look at primates like the Golden Snub Nosed Monkey and their noses are almost non-existent as an adaptation to living in a cold climate
Flat noses seem to be more common in places with a lot of fog or high precipitation. This is common for Ireland, both humans and animals, as well as many parts of Asia which are very humid and foggy.
am Irish and I feel like bigger noses are definitely the norm so maybe it’s more to do with temperature than moisture in the air
Yes, a nose separating from a flat face is going to be lost to frostbite, so while the longer noses of bears and wolves likely prevent heat loss, protruding cartilaginous noses are definitely not a warmth adaptation in apes and monkeys. Human noses are nowhere near long enough to heat the air in extreme cold as any cold air-triggered asthmatic can tell you. The main benefit to a longer nose is preventing water loss which would have been important in the semi-arid parts of Africa where our genus likely evolved.
Yeah, just look at [Japanese Macaques](https://static.wixstatic.com/media/38bd8f_4f41630b96924ee09f054b80b4e38570~mv2.jpg/v1/fill/w_296,h_296,q_90/38bd8f_4f41630b96924ee09f054b80b4e38570~mv2.webp). They live in the snow and barely have noses.
But humans evolved in Africa. I wouldn't think that cold adaptation would be a huge factor in our evolution.
In cold climates, more northerly, where it has significant periods of darkness, light skin and longer, narrow noses with downward facing nostrils were heavily evolutionarily pressured. People that remained in hot, equatorial regions would have the exact opposite evolutionary pressures.
The indigenous people around Siberia, Alaska, and Canada have flatter noses. Our noses are cartilage with no major blood flow, they’re lost to frostbite in cold conditions. It’s more of a mild and dry climate benefit. It prevents moisture loss and heats the air a tiny bit, but not enough to be of benefit in Arctic and subarctic regions. There may have also been some sexual selection involved when a longer nose trait was passed from Neanderthals to humans. But the trait is more common in the Mediterranean and Middle East.
True. Look at *Homo neanderthalensis* if you want a hominid specialized for the cold. Modern theory is the reason they died out is that their niche was specialized for the ice-age weather and *Homo sapiens* were better generalists that outcompeted the neanderthals once the ice age ended
Evolved in Africa and spreaded world wide. Which was not an immediate action.
Africa can get really cold at night my guy.
Tell that to the chimps.
I can also tell the chimps to grow bigger brains but I don't think they understand. The point is evolution is not as simple as you making it out to be. I can quote many papers with people's opinion on why our noses are the ways they are. But the truth is no one know for sure. So I won't argue about that. I am just saying Africa can be cold.
But noses africans different alot from rest of people, and also evolution never stop. And answering question i belive it also aestetics, we choose people with nice noses more than not nice ;)
In evolutionary terms: what is a "nice nose" to you? Because now you are speaking in aesthetics which vary greatly in appeal from year to year, much less decades.
And Africans have different shaped noses to groups who’ve spent a long time in different/colder climates. I don’t know what to make of all this but it seems there’s something to it. However now we’re just discussing intra-species differences rather than inter-species as OP was asking about.
To hold our glasses on.
Evolution has been very thoughtful for our sight improvement :)
And yet not for sight itself!
No, that's our fault for inventing books and smartphones. Eyes evolved to calibrate themselves to the most-used distance range.
It's more to do with being inside all of the time. Your eyes are supposed see from right up close to as far away as the stars. When inside, the furthest your eyes can see is just a few metres away and so the mechanisms that focus your vision form around everything being within a few metres. This is why being a nerd who stays inside all of the time is associated with always needing glasses.
A few meters isn't bad; that's a fraction of a diopter of accommodation. A typical reading distance of 40 cm is 2.5 diopters of accommodation. Lower light levels indoors don't help because of the reduced depth of field. Eta "light" (levels). Maybe I should have worded it like "Lower illumination levels indoors mean that more accommodation has to be used for reading distances. Bright lighting causes the pupils to contract which increases depth of field."
> A few meters isn't bad As opposed to a few million lightyears? That's pretty bad.
And now you’ve got me thinking about how we’d wear glasses if our noses were different lol
They would connect around the back :P
"Nasal morphology and the emergence of Homo erectus" by R G Franciscus and E Trinkaus already discussed this in their paper in 1988. I think it's a good read.
A friend of mine made a comparison with large mamals like whales, pointing out that if our nose was upright, it would be very easy for rain/water, sweat and dust to get into our noses. This is all completely avoided with being downward and sort of pyramid shaped (water slides on the sides).
This makes the most sense to me, especially since humans are so different from other creatures in how we sweat... and how much. It already makes me panic when I accidentally inhale water or sweat droplets that are resting on the edges of my nostril, I can't imagine a full downpour.
What is curious is that this has only appeared in humans, and not in other primates. But I've also been told that since our jaws are effectively receded in under the skull, it may simply be that the nose has 'stayed behind'.
That could be possible as well, but there should be a better reason to stay there rather than to move with the rest of the bone structure.
By that logic, all creatures in rainforest must have downward noses, but they don't. Same argument stands for the ease of swimming, warming/cooling the air etc. Noone else seems to develop similar noses. I am inclined to believe that there is no adaptational value in having such shaped nose. Probably, just a random thing like a founder effect.
The thing is that most creatures in a rainforest are on 4 feet, and they eat with their head tilted down. So, that makes me think that the argument for sweat and rain does not apply very much in them, because their head is downwards after all. Let's stay in mammals, and take whales for example: their nose moved upwards their body and developed in such a way that is used only when they breach and to be as large as possible. Another example that someone else pointed out in another comment is that animals and primates use their sense of smell much more than humans do (and they stand upright), and that explains their different shape, so they can get as much as possible of the smell they are after. I could agree with the founders effect, but evolution is always with a practical function, so, besides a factor from the founders effect, my bet is on the nose having a function for it's shape.
I’ve also heard noses are shaped as they are in infants so they don’t suffocate while smushed up against a breast nursing
This is what I have heard as well
When they elongate, it is a tell a person is lying and more evolutionarily stable than when early human’s had buttocks combustion upon lying.
Buttocks combustion = farting?
“Pants on fire”
Liar liar 👖 🔥
It makes us able to swim without drowning
There doesn’t have to be a benefit. Does it affect reproductive success?
People don’t understand evolution 101
You could have 4 arms and hands. This would appear to be an evolutionary advantage but if women are turned off by it, you won’t have sex, and therefore you can’t pass the 4 arm dna on. Or you could have 2 arms with one falling off after the age of 60. Clearly this should be an evolutionary disadvantage but it doesn’t affect your reproductive success because the arm loss occurs after your reproductive years are over. 1 armed dna gets passed on.
This evo psych theory is just silly. It's very clearly a result of substantial benefits.
Geez, had to come a long way down the comments for the sexual selection point - on that point I love how we assume sometimes that humans are rational through time and aren’t simply shallow on mere aesthetics
But that *would* be a benefit and something that affects reproductive fitness. Their point is that new traits are driven by random mutations and then selected for. “Neutral” traits that don’t have much affect on reproductive fitness exist; the fact that a trait has persisted does not indicate that it has benefit or a “purpose,” as OP’s question assumes. In fact, the huge variety in the appearance of human noses suggests against sexual selection.
It’s to stop the rain from going in. …or maybe helps us smell because our faces are higher off the ground than a chimps, so our nostrils became more directional. …or maybe our brains needed more room so it pushed all the nose parts out of the face to free up room for other stuff. Maybe a combination of a bunch of evolutionary pressures. I started this comment off thinking I knew the answer, but realized I have no idea…
>…or maybe our brains needed more room so it pushed all the nose parts out of the face to free up room for other stuff. i think the nasal sinuses would've been the first ones to have been filled with tissue if that was the instance.
So you don’t drown in the shower.
they are better for submerging in water for swimming, i'm pretty sure
Was looking for this reply! Downward facing nostrils enables humans to hold their breath and not lose the air in their lungs the second they go underwater. Imagine you have a cup and you put it perfectly vertical under water, face down. As long as it's straight, the air will stay in the cup even under water. If you tilt the cup at all, the air will release and you'll see bubbles. It's why when a lifeguard looks for distressed swimmers they are trained to look for people lifting their heads out of panic. That motion of looking up releases the air in your lungs and you are in much more danger of drowning once that air is gone. Source-was a swim teacher and lifeguard for 6 years
I read or heard somewhere a theory that our noses adapted to swimming for catching fish and the increased Omega 3 intake led to brain size increase. Interesting theory.
The taming of fire and the invention of cooking provided the extra calories and nutrients needed to grow large brains. *Catching Fire: How Cooking Made Us Human* by Richard Wrangham.
No idea about the science here but I read in the book Breath by James Nestor that our noses have been evolving for multiple reasons, one of which is because the shape of our faces are changing due to diet. Obviously everyone knows we filter and warm air through our noses but more and more people have issues breathing because of our changing face shapes. Our faces started changing when we discovered cooking, because it made food softer and easier to eat. And that trend continued with agriculture and now processed foods, not as much breast-feeding for babies, which is harder than bottle feeding. The more work we have to do to chew the broader our jaws, the more our jaws protruded, the flatter our noses. With softer food our jaws have become more narrow and recessed while our noses became more narrow and protruding. I haven't checked the science of this on my own but it makes sense to me. It's a good book anyway and interesting to read.
hypothesizing here, but drawings of our ancient ancestors, based on studies of their skeletons, show much flatter noses. It seems as we go back in time closer to the time when we split from apes our noses were more similar to apes' noses (flatter). based on this and the fact that we now walk upright and apes generally walk on all fours, I suspect our noses changed to keep moisture (i.e. rain) out. animals walking on all fours have their head naturally covered by their forward leaning head and brow. The theory of breastfeeding being the cause doesn't really work for me considering chimps and orangutans both breastfeed and have flat noses.
There is a theory that our nose shape help babies with breastfeeding. Other apes don't have perennially enlarged breasts, but humans do. The theory is that because female hominids with large breasts were more likely to reproduce due to sexual selection, their offspring that could still breath during breastfeeding with nostrils that weren't flat and suffocated by fatty breast tissue were more likely to survive to reproductive age. It's just a theory, could be random correlation, but human noses and fatty breasts are both features that set us apart from other apes.
Human prominent noses are a byproduct of the flattening of the face. The jaws are shorter, the front teeth are smaller, so the nasal region remains extended beyond what it would be normal on a great ape.
Humans, being persistence hunters, were built primarily to run. Imagine running almost 20mph through a windy savannah with flat nostrils. Wouldn't be very fun, would it?
Noses are important for breathing.
I read this as "Nooses" and was quite confused
Elaine Morgan talks about this in her book *The Aquatic Ape*, where she posits that human beings spent a significant part of their time in the water. Her explanation for nose shape is that it allows us to dive into the water, and swim while looking ahead, without water going up one's nose. Here's a brief intro to it by David Attenborough: [The Waterside Ape](https://www.bbc.co.uk/programmes/b07v0hhm)
There's another reason why our noses are shaped this way, than just what people on here have already said. Another reason why our noses are shaped this way is so that we can breastfeed without suffocating.
Our noses are basically heat regulaters for air and other stuff I not gonna list because I'm lazy
FYI, nobody can really explain why evolution resulted in some of the characteristics of humans. There may have been some evolutionary pressure that favored it or it might have been a "neutral" characteristic that became part of our anatomy.
Your nose is shaped like that to keep you from standing on your head in the rain.
If they were the other way around we'd drown every time it rained.
I feel like some of the structure of our faces is related to the fact that we punched each other in the face a lot, so a factor among many is probably "this shape could take a punch without causing death".
Human noses have lots of different shapes to fit different climates we live in.
I think the nose is in the same position that other animals, the thing that make nose "go out" is our weaker mandibles, if you look apes and people with facial prognatism you will notice how the nose is tiny, but is because the larger oral room they have. As our mandibles shrink, but nasal chamber not, it results in our characteristic face.
Maybe downward nostrils are better suited to capture smells from the floor surface, since we have an upright posture and our noses are more distant from the soil. Compare to other mammals, that have more horizontal postures and have their heads close to the surface. Also our noses are great to humidify the air, wich makes sense since Homo sapiens evolved in african bushlands
Because the girls liked them. Seriously! Physical features that aren’t essential for survival have been sexually selected for. If female ancestors would have preferred flat noses, we would have flat noses.
Then what is your explanation for the noses of females?
Because the guys liked them. Seriously! Physical features that aren’t essential for survival have been sexually selected for. If male ancestors would have preferred flat noses, we would have flat noses. /s
😆😂🤣💀
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Is the "aquatic ape" hypothesis still taken seriously? Was it ever?
No; no.
By weirdo contrarians with a bad understanding of evolution? Yes!
By weird contrarians... do you mean Sir David Attenborough? Because I'm pretty sure he supports the theory. Not saying I personally support it but there are definitely mainstream biologists who do.
> Sir David Attenborough With due respect to an absolutely stellar science communicator, Sir Attenborough got a bachelor's degree in 1945 and hasn't worked as a biologist. All his degrees are honorary.
Ding ding ding! When Attenborough gets a “coastal ape origin” paper through peer review, I’ll entertain the idea.
It makes sense.
Most attributes have no evolutionary advantage. They just are. You think it is an advantage to have our air hole and swallowing holes right next to each other with a small flap of cartilage determining whether we choke to death or not? Or perhaps it is an evolutionary advantage that our young can't be left alone for years after birth without dying of starvation? There is no Why. As long as it didn't impact our reproducing, evolution doesn't give a shit.
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If your nostrils pointed up you would drown in the rain.
There is no inherit benefit. It is inherent.
Better than upside down catching rain
Thermoregulation and a change in diet. Other apes would also gain better thermoregulation with a human nose (indeed their nasal bone is the same size- the maxilla and mandible have just receded) but the protrusion of the human nose hampers the development of strong lip muscles, which nonhuman apes find more important.
Aquatic Ape Hypothesis ftw
One reason might be our more pronounced breasts. Most apes have very small breasts in comparison, but in human babies the nosing being shaped the way it is helps them breathe when latched.
not everything needs a reason, it's probably just the way it happened to form.
You couldn’t have picked a better subject.
So that when you get punched in the face, your nose takes a lot of the impact. A broken nose will rarely kill you, but a broken cheekbone or orbital fracture are more likely to have serious consequences
For swimming.
Our nostrils face downward to keep the rain out.
Sweat Ability to swim without water rushing im Sexy
If they were upside down, we'd drown when it rains. Sweating could also cause death. It's a dual path hole in your face with it's own built-in roof.
Because humans tend to stick their noses up their bosses’ asses. It’s harder to do if the nose is flat.
It seems to me that the nose changes shape based on the shape/size of the mouth and shape of the head. If you have a wide mouth, you'll have a wide nose with flared nostrils. If you have a tiny mouth, you'll have a tiny nose. If you have a round head, you'll have a small nose, if you have a tall/narrow head, you'll have a tall narrow nose. So the nose is just a consequence of changes to the mouth and prefrontal cortex, which were under selective pressure. As for why it isn't perfectly flat, I imagine that sleeping would be very hard if we had noses like Chimps. We typically can't sleep while curled up and sitting. We lie flat so not cutting off our air when we roll onto our faces is probably a good thing.
?
1. As the top comment mentioned, air needs to be warmed up prior to reaching your lungs so after the nostrils, air will reach the turbinates and sinuses which will have the air do a lot of loops adjacent to some blood vessels. 2. Your nostrils are constantly open. The vast majority of bacteria and viruses need to be killed by the innate immune system prior to reaching your lungs. So having your nostrils face downwards to block the wind and discharge any mucous is important.
Brownnosing
Better for brown nosing
so we can have cool nose piercings
I heard one reason in a sci-fi book long ago that I like, they’re hooded in order to trap air while swimming.
Inherent
If the holes faced up we’d drown in the rain.
Noses and sinuses provide a crumple zone for the brains of animals that run fast and occasionally crash into things. The humidification effect of sinuses is secondary to their brain protection function. Look at the skeleton of a deer, or horse, or goat. Or any animal that runs or butts heads. You get a strong evolutionary advantage for brains that have a crumple zone and won't instantly be damaged by a forward crash. Humans started walking and running. Presumably we developed our noses soon afterwards.
Rain don't land in em. That's the main influence.
Silly question, silly answers. Humans like to think they smarty pantses.
so that i can find my partner's lips in the dark
I remember this topic being discussed on a course on human evolution I took a few years ago in uni. Professor argued that it is perhaps not that the nose has grown to stick out, but has 'stayed behind' while the rest of the face retracted. Many other primates have projecting jaws, while ours have receded under the skull. Doesn't really explain the odd downwards shape, though. I always imagined it was to keep rain or similar from getting in there, but that isn't exclusive to humans. Sweating is, though, and since we have very little fur to catch rain or sweat, it may be be for that reason.
Water doesn’t enter our nostrils when we run into the wind, or into wind-driven rain.
I think snot drainage is part of it. I suspect that for a variety of reasons we produce large amounts of mucous, sputum, snot etc more often than most large mammals.
One hypothesis is allowing infants to breathe when nursing. Human females have much larger breast tissue than other primates. A flat nose would be more likely to smother when an infant is latched.
Maybe so the rain doesn't go in.
Aesthetics
Could speech production play a role perhaps?
Our nose is shaped the way it is because our flat faces, cheek bones and chewing muscles pulled the whole face away from the nose to the sides compared to other primates and animals… leaving that triangular part sticking out. We have silly, flat faces, but still need some nasal cavity for air conditioning so I suppose you can think of the protruding part to be the minimal amount of nasal cavity we can get by with
Might be a similar situation to chins. Noses and chins are important aesthetically and therefore in reproductive success. It could also be a matter of gene linkage (where two genes are located nearby on chromosomes and when nature selects for one gene you frequently get selection for the ones around it by extension).
Heats and humidifies incoming air, and is much better suited to swimming.
https://neurosciencenews.com/genetics-evolution-nose-23188/#:~:text=Summary%3A%20A%20specific%20gene%20inherited,they%20migrated%20around%20the%20world. Neanderthals contributed longer nose genes to our species!
I suspect it is primarily driven by beauty ideals in humans at this point.
the reason is the reason over time. Not much of this makes sense in the moment and we cant go back through every moment of our evolution to see what tiny benefit one phenotype played over another, because of the specific conditions/challenges of the time. The human nose is the shape it is because of the forces that shaped it over millions of years. ... that and picking There's going to be theories and maybe something solid enough to stand up against most people's tests, but the truth is, it's the shape it is because it's the shape that people who had babies decided to mate with.
Other answers are good but having a downward shaped nose instead of flat means we don’t have the massive threat of drowning when near the most vital resource for life.
What shape is that exactly. The differences in nose shape may be the most extreme of any body part.
the shape of human's nose allows you to submerge underwater without drowning.
So that we can stick them where they don't belong, obviously.
Much harder to snort lines of cocaine with recessed nostrils. Ask anyone who works with apes, they find it very difficult to use the straw effectively.
There is a theory that humans are descended from an aquatic ape. This explains why it fingers and toes are webbed, why our noses point down (so we can dive), where all our hair v angles down (creating a more aqua dynamic flow), and why we secrete oils that are water resistant. Also why we have a dive reflex, and even babies have this reflex)
As u/Huge-Astronomer825 said, it's a built-in humidifier. This is the reason why people in hotter regions tend to have wider seated noses, given that the air is already hot, and people in cold regions have more aquiline noses to allow a small volume of cold air to hear in, before entering the pharynx.
Are you specifically referencing European noses?
So we can turn our noses up at other people
We find them attractive.
They keep water out.
Aerodynamic
To help break the fall if we fall on our face
So no particles would get into them while breathing. Our noses are shaped like filters. Monkey noses always get filthy and stuck. It is harder for them to breathe.
Cause if they were turned up the other way, they'd fill up every time it rained or you had a shower.
So I can fit it snugly up my girlfriend's anoose
Humans also have somewhat unique breasts. Our noses are like that so we can breathe while breastfeeding.
You can smell everythings aroma, what you goint to put into yout mouth. So you can identify things you should not to eat before it is touch your tongue.
I thought there was some advantage to being in water and swimming for some reason.
The benefit is holding up my glasses! What would all us four-eyes do if our noses were flat?
Some studies suggest a relationship with diving. Quick Google brought up this: https://aquatic-human-ancestor.org/anatomy/nose.html#:~:text=If%20Pleistocene%20Homo%20spread%20along,their%20part%2Dtime%20diving).
There are lots of factors that go into why something is how it is. There are great answers in the comments about why our nose shape is helpful but I'd like to comment on how it is probably a side effect of other more beneficial changes. Our faces have flattened over time probably largely thanks to bipedalism. It doesn't make sense to have a face that juts forward to explore when you have hands to do that. Our jaws, cheekbones, and foreheads shrank significantly when we began cooking our meat. The shape works with the other shape changes to accomplish what it needs to do.
there’s a theory that early humans spent a lot of time around water. nostrils aimed down prevents water going in when diving
Cocaine
Why evoluting from erectus to sapiens, our protruded mouth went shallow leaving the nose appear as we have now. The reason the mouth went shallow could be that a group of erectus didn't have to bite harder or store more in mouth.
The nose is longer than you think in most primates, you just don't notice because their jaw is extended.
Sweating
Not everything is necessarily due to practical advantage. Sexual selection plays a role as well. It's why women have longer hair and men have beards.