It's probably morning where you are, and you may find yourself surrounded by yawning coworkers — which makes you, in turn, break into a yawn. Why does someone else's yawn make you yawn? This cute video from TED-Ed offers a few theories, along with the science of yawning.
No matter how you slice it, nine months seems like an awful long time to spend cooped up in the womb, even if it is "biologically essential" or "how mammals work." We already know that fetuses kick, stretch, swallow, and even hiccup to pass the time, but sometimes they've just got to yawn.
Humans, chimps and other primates have all been shown to be susceptible to contagious yawning. Previous research has suggested that dogs are, too, unless — according to newly published findings — that dog is a puppy younger than seven months.
This video, by vsauce, not only explains why yawning is contagious, but also lays out the physiology of yawning, reveals that you're less likely to yawn when your brain is cool, and gives us some delightful clips of parakeets yawning.
If you ask people why they yawn, the most typical answer will be "because I'm tired." But sleepiness and boredom might not be the real reasons behind yawning. It actually might be a way of getting rid of hot air.
Just like humans, chimpanzees yawn when they're bored or sleepy, and they also yawn contagiously when they see another chimp do it. That discovery could help unlock the secrets of human empathy.