Weird Al Says: WTF?!

Although we associate yawning with sleepiness and boredom, its function appears to be to wake us up. Yawning expands our pharynx and larynx, allowing large amounts of air to pass into our lungs; oxygen then enters our blood, making us more alert. Many vertebrates do it, including all mammals and perhaps birds. It also has been observed in human foetuses after just 12 weeks of gestation. In non human primates, it is associated with tense situations and potential threats.

Think of yawns as your body's attempt to reach full alertness in situations that require it. They are contagious, as anyone who has attempted to teach a roomful of bored students knows. No one is sure why, though it might be advantageous to allow individuals quickly to transmit to one another a need for increased arousal. They are not contagious in non primate mammals, but the ability to recognise a yawn may be fairly general: dogs yawn in response to stressful situations and are thought to use yawning to calm others. You can even sometimes calm your dog by yawning.

This has been a moment of ... WTF?!