👉 Yawning is a common and often humorous behavior in which the mouth opens slightly as if it's about to cry out, usually due to something being too hard or too cold. It can be done by moving the lips upwards or downwards while closing them again. Yawning is an example of the respiratory process and is part of our body's natural defense mechanism against stress. Yawning has been observed in animals as early as 30 million years ago, and it is a common behavior among humans as