Does yawning have a function, or does it just happen?

Question

Does yawning have a function, or does it just happen?

Answer 1

There is actually quite strong evidence that yawning does not increase blood oxygen significantly in man. The current belief in the field is that yawning is for social communication - we yawn most often right after we wake up, and right before we go to sleep.

Yawning is contagious. Actually beyond humans - very recent studies have shown that dogs can catch yawns from people.

Also worth noting that yawn like things in other animals have nothing to do with sleep. Many primates open the mouths in yawn like gestures to show their teeth, and intimidate potential predators.  

Answer 2

I've read somewhere that when your brain is not getting enough oxygen, you yawn to increase the level of oxygen.

Answer 3

I read somewhere it's to reinforce our bond as a social group, to advertise that you're tired to others. So that our sleeping patterns synchronize and we can all go hunting in the morning as a group.

Answer 4

all i know is that over yawning i know is a sign of a possibly health condition. i think where a muscle pushes up against your vegas nerve and makes you yawn like crazy.

Answer 5

Researchers don't know the actual purpose of yawning for certain, but a lot of good points are brought up here. I'm not sure about the validity of this, but I was taught that chemoreceptors in the medulla of the brain detect higher concentrations of carbondioxide and this causes the individual to yawn.

ANSWER:

When we normally breathe we do not use nearly the full potential of our lungs. The alveoli near the bottom of the lung receive little oxygen and partake in relatively little oxygen exchange. Yawning causes the lungs to fully fill up with air and hold it that way for a short period allowing the diffusion of gas to reach its full potential for a brief period.

Answer 6

It definitely has a function.  Most often, it's an effort to increase the amount of oxygen in your system.  There are also theories that it was one of our first methods of communication - that before we developed language, it was a signal to the tribe that it's time for bed.

Answer 7

Medically speaking, yawning is our way of trying to take in more air.