• Question: why do we yawn?

    Asked by saraw to Adam, Chris, Eleanor, Jessamyn, Sinead on 11 Nov 2013.
    • Photo: Eleanor Holmes

      Eleanor Holmes answered on 11 Nov 2013:


      As far as I’m aware we yawn in order to get more oxygen into our lungs when our bodies feel we need it. So if you are in a room with less oxygen than, say, a fresh hilltop, you might yawn to get enough oxygen. Also when you are tired you tend to breathe shallower so every now and then your body tells you to yawn to fill your lungs again.

      Why yawning is contagious? I have no idea. But we do tend to match our breathing rate to other people in the room with us. There is an incredibly sweet practice in maternity hospitals of putting a strong baby with healthy lungs in the crib with a premature baby with weak lungs and the premature or sickly baby will breath stronger to match the healthy one. Amazing.

    • Photo: Adam Murphy

      Adam Murphy answered on 11 Nov 2013:


      There’s a few different theories as to why we yawn, but no one’s really sure. Some people say it’s to get more oxygen into your lungs, like Eleanor says. There’s also the idea that it might just be to give your breathing muscles a good strectch!

      This wouldn’t explain why it’s contagious though. The best one for that it’s used a signal to other animals that live in groups: “Hey, I’m tired, let’s all be tired and find somewhere to sleep where we won’t get eaten.” It’s similar to how wolves howl to signal a hunt.

      These are all the ideas floating about at the moment, all I can say for sure is that I love a good yawn.

    • Photo: Sinead Cullen

      Sinead Cullen answered on 11 Nov 2013:


      Hi Sara,
      There a few theories about why we yawn,but no one can say exactly why. Apparently when we get tired or bored our breathing gets shallower and we do not take in as much oxygen as we would normally so we yawn to try take in more oxygen into our lungs.
      I read somewhere before that yawning is contagious because your brain thinks that the person you see yawning is stealing all the oxygen around you so you feel you have to yawn too!

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