why do humans yawn?

Answer 1

It's a reflex. I yawned just reading your question.

Answer 2

Science has offered no real answer just hypothesizes, It is a rather interesting phenomena though, also why is yawning addictive.

hmm noticing a common error about oxygen, want a fun experiment... try yawning then try taking in a deep breath, you actually take in more air and faster witht he deep breath as opposed to the yawn, so the lack of oxygen is not the key.

Answer 3

i looked in the dictionary a long time ago.

it's the need to inhale, when your brain isn't receiving enough oxygen, your body feels the need to yawn. so, when you're sleepy, your body starts to slow down, including your breathing. but, you're still awake and moving around, which means your body needs more oxygen to do those things. so, you yawn.

do you get it?

to prevent from yawning, i take deep breaths... most of the time this works.

Answer 4

If you're tired you tend to breathe slower. Your body is actually taking a big breath when it yawns. Why it's contagious, I don't know. Makes me want to yawn just thinking about it.

Answer 5

Humans yawning is a result of hypoxia in central nervous system!!it is an accomodating mechanism by the help of it we get rid of oxygen disbalance in CNS!!!

Answer 6

When we get tired we slow down our breathing. We yawn to fill our lungs with oxygen. Take note next time you yawn, bet your breathing slowly and shallowly about to ........ doze.......off.....an ..... :O you feel a little refreshed from the burst of oxygen.

Answer 7

animal instict from cave man days , one howls all howl.
we yoused to have yawn corner comin home from work every day someone would yawn and it goes on around the car
damn you i just yawned twice thinking about yawning
HOOOOOWWWWLllllll hehe

Answer 8

When the brain needs oxygen in large amounts then it is not possible to inhale it all through the nose at once.Therefore we open our mouths wide and take in large amounts of air at once.It means our brain is slightly tired.

Answer 9

We yawn, when the brain isnt getting enough oxagen. Thats why we do it when we are tired, our breathing slows down.

Answer 10

lack of oxygen to the brain, thats why when i do shrooms i yawn so much!