European Tree Frog (Hyla arborea) yawning on a Bramble (Rubus sp.) bush in the forest in Noord Brabant in the Netherlands© Henk Bogaard/Shutterstock.com You know the feeling. It’s getting close to ...

Tiredness, sleep deprivation, or certain medications usually cause yawning. If you find yourself yawning much more than usual on a daily basis, there could be more than tiredness or boredom going on.

Open your mouth wide, stretch the muscles of your jaw and upper body, take a slow breath in, and then exhale quickly. What have you done? You have yawned. Many animals, including humans, yawn. They do ...