Why do we yawn?
Yawns are natural and healthy for you. When we yawn, we are helping our breathing. A yawn is a very deep breath in which big gulps of fresh air are pumped into our lungs, supplying our blood with more oxygen.
Usually, we yawn when we are tired or drowsy and our bodies are relaxed. It is a sign that the body needs sleep, but it can mean other things, too
We may also yawn when our bodies are not getting enough fresh air. Then we may need better ventilation, or exercise. One purpose of yawning may be to awaken a person by stretching the muscles and helping the blood to get things moving again. You don’t yawn when you wake up. Yawning wakes you up!
Suggestion also causes yawning. When we see others yawn, we are likely to yawn. You may be yawning now, just from reading this. And yawning is common in animals, too. Dogs, cats, monkeys and turtles yawn. So do birds and most if not all, backboned animals. – Dick Rogers