Why we yawn.
A team of scientists has a new theory to answer an age-old question: Why do we yawn?
All vertebrates (animals with a backbone) yawn--even birds. So to study the role of yawning, biologists at Binghamton University in New York turned to parakeets. The researchers found that birds placed in a room that became increasingly warmer versus a room at a constant temperature yawned twice as much.
The team suspects that drawing in a deep breath could be the body's involuntary way of cooling the brain. This theory would explain why tired individuals yawn, since exhaustion has been shown to increase the temperature of the brain.
It would also suggest that yawning has nothing to do with boredom. "This is a brand-new and radical way to think about yawning," says Andrew Gallup, who led the study.