What D'ya Know...? -- Yawning

So I'm starting something new: a monthly "What D'ya Know" segment that will feature (I hope) interesting topics that everyone just knows about but not really the why.

We know yawning is contagious but why? We know in Jeopardy, they always start with "What is..." but why? We know cat's have whiskers, by why (lol, true story--a friend asked me why my cat's had such long whiskers and I thought that's a good question...).

But because of my random mind--and nosey nature--I like to know a little of a lot, to be able to satisfy my "well, why is that?" questions. And I thought I'd share my findings. But be warned, I don't claim to be an expertise in any of this! This is just plain, ole Google research (which may not even 100% accurate) but I hope you find them interesting, fun, and enlightening...

So, why is yawning  contagious?

We all know we yawn when we're tired. But the phenomenon is being next someone who yawns and giving into the urge to do the same. This was a hard one to get to the bottom of. Scientist have so many theories that I won't even begin to get into (something about a tiny part of the brain activating an unconscious response...) but other speculations include:

1. It is a subconscious way to show empathy and a form of social bonding

2. Yawning boost brain function and contagious yawning is a way of keeping the group on high alert (hmmm, sounds far-fetched...)

3. Lack of oxygen makes us yawn, so in a group people will yawn to inhale more oxygen

But nevertheless, there is no real answer to this--just theories. But it's interesting to note that all animals, mammals, reptiles yawn. Humans being yawning as early as 11 weeks in the womb but contagious yawning doesn't start until age four. And apparently not everyone experiences contagious yawning--only about 40-60% of healthy adults yawning after seeing someone else do it.

What a mystery... What are some of your guesses as to why yawning is so contagious?