Some time ago, I posted a blog here about yawning, defined by Merriam-Webster as opening the mouth wide and taking a deep breath, usually as an involuntary reaction to fatigue or boredom. It is often accompanied by stretching and is generally considered a symptom of sleepiness.
The word “yawn” has been in our spoken language for many centuries. It derives from Middle English (which the Oxford English Dictionary says lasted from 1150 to 1500) word yenen or yanen, from the Old English ginian; akin to old High German ginēn (to yawn) and to Latin hiare and Greek chainein. Yawning is a practice shared by humans with many different animals. And there is even a field of scientific study of yawning called chasmology.
Yawning is universal among humans and advanced animals. We humans yawn an average of 20 times a day. Most of us try to squelch yawns while in polite company because it is considered impolite, a sign of boredom.
The problem is that there is no agreement among experts as to what causes yawning. Theories range from: a belief that yawning occurs when one’s blood contains increased amounts of carbon dioxide and therefore becomes in need of the influx of oxygen (or expulsion of carbon dioxide) that a yawn can provide; to a hypothesis that yawning, especially psychological “contagious” yawning, may have developed as a way of keeping a group of animals alert.
And the contagion of yawning is well established. If I yawn, the likelihood that others around me will yawn is high. Even a yawning animal nearby can trigger a yawn in me. And in the years when I had dogs and cats when my children were growing up, I noticed how often one of them yawning could cause me to yawn and vice-a-versa.
So here I am, subject to universal behavior I can’t explain that most others consider rude. Sometimes I think we don’t give enough credit to how difficult to understand life is, especially if you associate with others of the species.
Tom Glenn, Writer 