Is it true that we yawn when our brains are deprived of oxygen? Most of us can feel a yawn coming on. The muscles in our jaw begin to tighten, our nostrils might flare, and our eyes might tear up ...

Yawning is sometimes associated with fatigue ... the contractions causes the air to make the rumbling sound we know and love, or borborygmus to give it its scientific name. Its links to hunger ...