What's the body's goal in making us yawn?

[JPC]

hey just wondering

why do we yawn when we are tired ? Whats the body's aim in making us yawn ?

 

[jim mcnamara]

There isn't massive agreement about the why, but soem agreement about what happens:

http://www.howstuffworks.com/question572.htm

 

[moe darklight]

this is my own personal observation so there's no science or research behind it... but I've always noticed that yawning feels more like stretching than breathing for oxygen. We always stretch our muscles when we just wake up or have been passive for a long time (like our back and neck and legs), these are also the times we most likely yawn... could yawning simply be a way of stretching those internal muscles and jaw muscles?

 

[Mk]

I learned how to yawn at will or keep myself from yawning if I wish it. How common is that? I found it helpful for pressurizing my head when I lived on top of a mountain and had to drive up and down it everyday.

 

[JPC]

this is my own personal observation so there's no science or research behind it... but I've always noticed that yawning feels more like stretching than breathing for oxygen. We always stretch our muscles when we just wake up or have been passive for a long time (like our back and neck and legs), these are also the times we most likely yawn... could yawning simply be a way of stretching those internal muscles and jaw muscles?

hum that sounds coherent

and also does contradict Mk's message

sometimes u really feel like u want to stretch, and u can stop urself from doing it
you can also strecth when u want to

for yawning seems a bit the same, except its a bit harder to control it

-------------------------------------

IF only humans yawn THEN

it has to give an advante over an human who doesnt/cant yawn
because every human on Earth yaws

this means that during our evolution, those who didnt yawn must have had at least a small disvantage

ELSE

' same thing , but with the related animals, thus might be really complicated coz we would be going more back in evolutionEND IF