Hacker News Reader

Comment by carapace | Hacker News Reader

There are several oddities about humans that seem to indicate that we were semi-aquatic at one time: webbed fingers and toes, hairlessness (compared to other primates and hominids, we are the "naked ape"), our big beak noses that help keep water out of our nasal passages (some people can voluntarily seal their nostrils), our babies float and instinctively hold their breath, the fine hairs on our backs are slanted towards our spine (rather than away like all other primates) improving flow, our fingerprints that swell and wrinkle when wet making it easier to grip things, our eyes have a special "underwater mode", etc.

View on HN

Voluntarily sealing your nostrils is something I never knew about until I was complaining about some city odor to a girlfriend who said "Just plug your nose." I said I didn't just want to walk around pinching my nose, and she gave me the most incredulous look. She was like "No, just do it without touching your face..."

This definitely shocked me. May as well ask me to sprout wings and fly!

Here’s how it went with my wife.

Me: I wonder why our son doesn’t like to get his head wet in the bath or the pool.

Her: I think he doesn’t like to get water in his nose, like me.

Me: uh... what?

Her: blah blah blah

Me: WHAT DO YOU MEAN YOU CANNOT CLOSE YOUR NOSTRILS FROM THE INSIDE?!

Or something like that. I guess I assumed that everyone could just block it off from the inside. It’s apparently not something that comes up very often?

Wife: can you pick up that pencil off the floor please?

Me: picks up pencil with foot.

Wife: WTF?

I used to to that when I was a kid but then I started sweating...

Don’t we all naturally seal our nostrils from smell when we use non-nasal sounds? Think a nasal ahhhh sound versus a non-nasal ahhhh sound.

Although I am guessing sealing nostrils from water versus from smell is distinct: I feel you can seal at the front “inside” the nostrils (think blocked nose) versus sealing at the back (soft palate?). Edit: Also when you blow your nose, i think you partially use the muscles that close off the nasal passages?

Although quite possibly I am misunderstanding something - we often struggle to even realise what we naturally do (e.g. when swimming) or struggle to understand that others do things differently.

I tried to exhale through my nasal passage and then block it off with just the muscles in my nostrils, building pressure in the nasal cavity. I cannot do that.

Wait, what? People can do that?

That's the coolest thing since a friend showed me he could move his ears.

I just looked it up and found this pdf[0] on some technique for divers I didn't bother to understand, but it contains an instruction (Step 3: Learn to control the soft palate) how to get a feel for this. It's not really nostrils, but I think this is what GP meant.

[0]: https://freedivewire.com/wp-content/uploads/2016/11/frenzel....

I'm no professional diver but thinking about it and reading that link, it's really a technique to maintain enough pressure inside the nasal cavity to prevent water from rushing in, achieved by closing the soft pallet then slowly moving air into the nasal cavity as needed to maintain that pressure. So not really closing nostrils (for me at least) just restricting them a bit I think... it still sucks to get water past the nostrils but that can be prevented and it's not something I've really had to think about before. When diving into water or changing depth I have to exhale hard through the nose to combat the surge of water pressure but after that it just happens.

I do it by pushing my top lip up against my nostrils. I look silly if there's someone with goggles on to see me underwater, though. Like an extreme duck face.

Also, it doesn't work well now that I have a mustache.

You can't? Have you tried it?

I'm not sure how to start trying it. I can move my nostrils a bit, but it's more to expand them : I don't have any muscle 'plugging' them it seems

Or are you supposed to plug from the inside, with your tongue blocking the top of the mouth kind of ?

I don’t know about others but I don’t use my tongue. I can block my nasal passage and breathe through my mouth. I can have my mouth wide open and do this. It must be controlled by some muscle but I don’t know what.

you can either breath through nose or mouth not simultaneously. I thought this is normal ..

I am pretty sure I am breathing through both right now (trying on purpose to do so). I can definitely feel the breath on my tongue and hold something to my nose and smell it.

Whether air from both places actually goes into my lungs? That, I don't know. So you may be right in that regard? I really don't know. :)

Are you sure about that? I don't think that's true, not for everyone at least.

I can breathe through the nose, the mouth, and also through both at the same time.

"both at the same time" blew my mind!

For me this is the norm. I can breathe through my nose, or my nose+mouth at the same time. There is no "just breathing through mouth"

"No, just do it without touching your face..." -- doesn't that simply mean "stop breathing"? because that has the same effect. I do this all the time these days when I walk past people and not waring mask ;-)

Jokes aside apparently people can do this while still breathing through their mouth

I think that has a lot more to do with enabling us to walk, jog, and work long hours by sweating to keep cool. More water lost, but huge competitive advantage in endurance. Since we're literally oozing water, I'm guessing all those water-adaptive advantages start to make more sense for landlubbers.

Interesting. I happened to be one of those natural born swimmers (not as newborn) as an infant as I could float, move around by wiggling like a fish and close nasal passages instinctively (w/o exhaling) at 8 months. Always perplexed me that some people will hold their nose closed or have to exhale through it while under water.

> our babies float and instinctively hold their breath

This is just partly true, however, and I assume you don't mean that babies are natural born swimmers. :) Ref. Wikipedia; "Babies are not old enough to hold their breath intentionally or strong enough to keep their head above water, and cannot swim unassisted. Most infants, though not all, will reflexively hold their breath when submerged to protect their airway and are able to survive immersion in water for short periods of time." [0]

[0] https://en.wikipedia.org/wiki/Infant_swimming

We put all 3 of our kids through ISR (Infant Swim Resource). they started at 9 months (based on summer relative to their birthdays). Its pretty incredible to see a 6-9 month old baby float indefinitely. At a year, they teach them to "swim, float, swim". The swim phase is targeted to 5-7 sec of holding their breath while swimming.

https://www.youtube.com/watch?v=jeY9zYkNf7M

Yep, the semi-aquatic simian theory to explain bipedalism. If I remember correctly, It was disproven yet when we studied it in anthropology course.

Isn't the hair stuff mostly explained by running on two legs and thermal regulation ?

Yes. Also, most every mammals other than whales _still_ have fur (seals, sea lions, otters, etc), so it's not clear that hairlessness has strong selection pressure.

When thinking about what water humans had a contact with at one time you should rather think of hippos not otters.

Shalow, warm, maybe even not salty water? It must have been significant food source if we have very specific adaptation to gipping something in water.

Pruney fingers are a general primate adaptation, and likely have more to do with not slipping from trees when it rains than any serious aquatic phase.

Not that general. The only other species I can find mentioned to have pruney fingers are macaque monkeys.

And we are unsure if that's a remnant of common ancestor or a parallel evolution.

My cousin can do it with his upper lip, he just moves it up like a flap and it covers both nostrils!

Also, humans enjoy being near large bodies of water. (oceans, lakes, etc.)

Yes. The price of seafront property is a strong indicator or our aquatic past.

I would definitely read a paper with this as the premise, regardless of the quality of the research.

Reply on news.ycombinator.com