By EVANGELINE COMEAU-KIRSCHNER, age 11

Photo courtesy Arctic Wolf/Flickr
Photo courtesy Arctic Wolf/Flickr

Scientists have confirmed that the bigger your brain is, the longer your yawn lasts. They watched 205 different videos of animals yawning on YouTube and found that humans yawn the longest, for precisely 6.5 seconds. That explains why animals with bigger heads than humans have shorter yawns, because they have smaller brains proportional to their bodies.