Yawning is a fascinating behaviour. Why do we – and lots of other animals – do it? Its purpose has been mysterious since we first noticed that we did it.
Discovery News is now reporting that the main reason for yawning is thermal control of the brain. Our brains, like computers, work better when they’re cooler, and yawning acts like your car’s radiator. A sudden intake of air – so long as it’s cooler than your body temperature, or at least the temperature of your head – will cool the bloog in your face and, shortly thereafter, your brain.
Photo from twob via Creative Commons license