Wonder Contributors

We’re revisiting today’s Wonder of the Day thanks to the suggestion of several Wonder Friends, including Vannessa from Florida, Maya from Vermont, Kyle from Ohio, Corrie from Connecticut, Karen from Virginia, Jolie from Kansas, Charis from Texas, Meghan from California, Ryan from Iowa, Ainsley from Indiana, and Miss Habben’s First and Second Grade Classes from Iowa! Thanks for WONDERing with us!

Yaaaaaaawn. When it comes to yawns, two things are certain: Everybody yawns — and nobody really seems to know why.

We begin yawning very early in life — before we’ve even entered the world, to be exact. Ultrasounds have discovered that fetuses begin yawning and hiccuping as early as 11 weeks into their development.

There are several theories about why we yawn. One theory suggests that we don’t breathe as deeply when we’re bored or tired as we do when we’re excited or exerting energy.

When our breathing slows, our bodies receive less oxygen. This reduction in oxygen makes us feel tired and lethargic.

Yawning helps bring a burst of fresh oxygen into the blood while pushing carbon dioxide out. If this theory is correct, yawning is an involuntary reflex.

More recent research suggests yawning may be a way our bodies distribute oily substances called “surfactants” that lubricate the lungs and prevent them from collapsing as we exhale and inhale.

No matter which yawn theory you believe, one thing is for sure — yawning is contagious! If you’ve ever watched someone else yawn, it’s likely you’ve caught the yawn, too!

Scientists continue to study the “contagious yawn” phenomenon, but they’ve yet to conclude exactly what causes humans to yawn simply because they see another person yawning. Interestingly, their research has found that, like humans, chimpanzees will yawn when they see another chimpanzee do so.

The next time you get an urge to start a trend, just open up your mouth and yawn. You may be surprised to find the person next to you can’t resist the urge to join in, too.


59 Join the Discussion

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  1. It’s funny how sometimes reading about yawns or seeing someone else yawn causes us to yawn, too, isn’t it, “Wonder?” Thanks for leaving us TWO great comments! We’re glad you explored this Wonder of the Day®! :-)

    • Even thinking about yawning can cause you to yawn– how crazy! Thanks for sharing your comment, Matthew! We’re glad to have a great Wonder Friend like you! :)

  2. I was yawning like crazy in class today. I would do it every 5 minutes uncontrollably. Also every time I did my eyes watered. Think I ate too much turkey. ha ha ha.

    • Turkey can have that affect on us, Tyler J! We’re yawning just thinking about you yawning! We’re glad you have been WONDERing about yawning… but we’re off to bed! :)

  3. Hehehe! This video was super cool! And, I watched it in school with my friends because we wanted to know WHY we yawned so much in class! So we found this and we kept YAWNING and YAWNING until there were tears streaking down our faces but thats O.K cause we were laughing too, mostly! I’m glad we WONDERed!
    :) :) :) :) :)

    • Hey there Annie! We’re glad that you and your friends have a better understanding of yawning– and its power! We are yawning just thinking about yawning! :) We’re glad you WONDERed with us, too! :)

    • Well thanks so much, Kate! We are so happy to hear that you enjoy Wonderopolis! We’re glad you’re here with us, too! :)

    • It’s cool how that happened, Carlos! We think it’s WONDERful that you shared your yawning experience with your friends in Wonderopolis today! :-)

    • Oh boy, we hope we didn’t put your class to sleep, Madeline! We know the feeling… we’re yawning just READING your comment about yawning! They sure are contagious, but we’re glad you are still awake to Wonder with us! Thanks for sharing your comment! :)

    • We understand, BlueTooth! Scientists have a few ideas about why we yawn, but we do not know for certain…yet! Do you have a guess? :)

    • That’s a good question, addyson rice! Maybe you could find more information about yawning at your library. Thanks for WONDERing with us and keep up the great thinking! :)

    • Hi Aria! We are glad you enjoy visiting WONDERopolis. We think it is pretty fantastic too! Have you ever noticed yawning can be contagious? If someone around you yawns, you often do too. Did that happen while you were reading the WONDER? :)

    • Hi Trazariya! When we are bored they do not breathe as deeply, so we do not take in as much oxygen. We yawn to get more oxygen and release carbon dioxide. What is the other yawning theory described in the WONDER? Have a WONDERful day! :)

    • Welcome, Charity! The WONDER tells us two reasons for why we yawn. Look back at the WONDER for this information. However, scientists don’t know why yawning is so contagious. Have you ever found yourself yawning just because someone around you yawns? It’s crazy how contagious it is! :)

    • Thanks for commenting, Jahirah! Scientists are not sure exactly why yawning can be contagious. Has this ever happened to you? Have a WONDERful day! :)

    • That’s right, Leah! Scientists found that like humans, yawning is contagious for chimpanzees. We WONDER if other animals yawn too. Thanks for sharing your new learning with us! :)

    • Great question, Gregory! Scientists have found that fetuses begin yawning and hiccupping as early as 11 weeks into their development. Check out this WONDER about hiccuping! Enjoy WONDERing!

    • Hello Marcus! The WONDER tells us that we yawn more when we are tired or bored because we are not breathing as deeply as when we are excited. Yawning helps us get more oxygen and releases the carbon dioxide in our body. That’s probably why you were yawning before going to bed. Thanks for sharing! :)

    • Great information, Sage! Why do we need to take a deep breathe? Do you remember from the WONDER? Keep up the great thinking and thanks for sharing your learning with us! :)

  4. When you yawn that means that you are just tired or you need to rest and when you yawn everybody else has a response of yawning like dogs and whales they have connection because when the mother whale losses his baby they make a noise and they get a response

    • Interesting facts, elexeanna! Thanks for sharing! Do you know why we yawn when we are tired? Look back at the WONDER and let us know what you find out! Have fun WONDERing! :)

    • We are glad you learned something from this WONDER, Emily! It is interesting that scientists found that to be true! We WONDER if it is true for other animals! :)

    • We are glad you loved this WONDER, Mrs. Martinez! We love when classes are learning and having fun at the same time! Always keep WONDERing! :)

    • Hello, stella! We are glad you enjoy WONDERing, too! We love hearing from our WONDER friends and appreciate them joining the discussions on WONDERopolis! :)

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Have you ever wondered…

  • Why do you yawn?
  • Is yawning contagious?
  • Does everybody yawn?

Wonder Gallery

Wonder #35 - Yawn Static ImageVimeo Video

Try It Out

Does all this talk of yawning have you feeling sleepy? Wake up by checking out the following activities with a friend or family member:

  • A Native American tribe called the Ojibway believes that hanging a dream catcher in their bedrooms will protect them from bad dreams. According to the legend, the center of a dream catcher allows only good dreams into the dreamer’s mind, while the surrounding web catches all bad dreams. When the sun comes up, the bad dreams trapped in the web disappear. Want to make your very own dream catcher? The Dream-Catchers.org website offers detailed instructions. Put your imagination to work so you can catch some extra zzzzs while your dream catcher does some catching of its own.
  • Why do you think people yawn? Do you agree with the theories discussed in today’s Wonder of the Day? Or do you have some ideas of your own? Can you come up with any additional theories that might make sense? Think about the times you tend to yawn. Then think about how you sometimes yawn when you see other people yawning. Can you think of a theory that might explain why these things happen how and when they do? Have fun brainstorming some ideas like a real scientist! Share your ideas with friends and family members. Do they think your ideas have any merit?
  • Up for a challenge? Do some yawning research of your own. Without telling anyone what you’re doing, sit down in the midst of friends and family members as they’re going about their day-to-day activities. Force yourself to yawn loudly a couple of times, and then observe the people around you. Does anyone nearby “catch” your yawn? If so, how long does it take for others to start yawning? You can test reactions repeatedly by continuing to yawn at different times. For fun, do the same thing around your pets. Do dogs or cats yawn if they see you yawning?

Still Wondering

Head over to Science Netlinks’ Bottled Model Lungs lesson to  build a model of the respiratory system and investigate the inputs, outputs, and interactions of the parts in the system.

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