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Tell Me Why #5 – Why Do We Yawn & Are Yawns Really Contagious?

Team StoryWeavers|March 23, 2022, 06:39 IST| 57

Welcome to BYJU’S ‘Tell Me Why’ where we explain to you the ‘why’ behind anything and everything that’s been on your mind! So go ahead and ask us a question that starts with ‘Tell Me Why’. We’ll pick the most intriguing questions and feature them along with an illustrated answer on The Learning Tree Blog.

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Today we are answering a very interesting question asked by class 8 student Dashmeet Kaur from Bhilai, Chhattisgarh. She wants to know:

Why Do We Yawn?

Everybody yawns — from unborn babies to the oldest great-grandparent. Animals do it, too. But why, exactly, do people and animals yawn? 

Well, there are plenty of mysteries about the human body, and yawning is no exception. No one knows for sure but there are many theories about why people yawn. 

We typically think of yawning as an indication that we’re tired or bored, but some people report yawning more frequently when exercising or while singing. So, if it’s not just a sign that we’re sleepy or bored, why exactly do we yawn?

So how much of yawning is mystery and how much can science actually tell us about yawns?

The theories of yawning

Yawning is a reflex characterized by a single deep inhalation (with the mouth open) and stretching of muscles of the jaw and trunk. It occurs in many animals, including humans, and involves interactions between the unconscious brain and the body, though the mechanism remains unclear. 

There are many theories as to why people yawn. For many years, it was thought that yawns served to bring in more air because low oxygen levels were sensed in the lungs. 

We now know, however, that the lungs do not necessarily sense oxygen levels. Moreover, foetuses yawn in-utero even though their lungs aren’t yet ventilated. In addition, different regions of the brain control yawning and breathing.

Another reason you may yawn is because the body wants to wake itself up. The motion helps stretch the lungs and their tissues, and it allows the body to flex its muscles and joints. It may also force blood toward your face and brain to increase alertness.

Other people believe that yawning is a protective reflex to redistribute the oil-like substance called surfactant (say: sur-FAK-tint) that helps keep lungs lubricated inside and keeps them from collapsing.

Why do I yawn even if I am not tired?

That’s a great question! And it’s the same question that made scientists debunk the theory about yawning when we are tired. The most scientifically backed theory about why we yawn is brain temperature regulation. A 2014 study published in the journal Physiology & Behavior looked at the yawning habits of 120 people and found that yawning occurred less during the winter. If the brain’s temperature gets too far outside of the norm, inhaling air can help cool it down.

You yawn when you’re
Seeing someone else yawn
Your brain slows down, causing drop in temperature
Your brain isn’t feeling stimulated
You are exposed to the same temperature as others


By now, you must have understood that there is no one answer to this seemingly simple question about why we yawn. Scientists are still breaking their heads over it. But there is one part about yawning that has got everyone puzzled for years: It seems to be contagious!

If you yawn in class, you’ll probably notice a few other people will start yawning, too. Even thinking about yawning can get you yawning. How many times have you yawned while reading this article? We hope not many!

Is yawning really contagious? 

Yawning is definitely contagious. Even videos of people doing it can trigger a yawning session. Try watching the video below and see if you end up yawning. Tell us in the comment section if you did catch a yawn or not. 

Similar to the mystery surrounding why we yawn, experts also aren’t really sure why yawns are so contagious.

Some scientists suggests that yawning is a means of communication. We express the change in environment or internal body conditions to others through yawning. If so, then its contagious nature is most likely a means of communication within groups of animals and humans, possibly as a means to synchronize behaviour. 

In the context of the brain-cooling theory of yawning, perhaps yawning evolved to become contagious as a means to increase the cognitive performance and vigilance of people within a group. While this may sound silly in today’s world, it could have been an important collective behaviour for our cave-dwelling ancestors who needed to stay alert as a group in order to survive.

While it’s not clear what yawning truly communicates, some experts believe that the contagious nature may also be a way of showing empathy and matching the emotional states between people. In fact, a recent study shows that we’re more likely to experience contagious yawning with our closest acquaintances than we are with strangers.

So, the next time you yawn, think about whether you’re tired, bored or neither, and also if you’re yawning on your own or you’re yawning because it’s just on your mind! 

Also tell us in the comment section which of these theories of yawning you find most acceptable.

Also read, Why do we laugh when tickled.

About the Author

Raza has been writing since 2008, be it fiction, poetry, or articles on science, politics, and history. He believes that words can change the world, and he uses them to inspire and empower people through his writing. When he is not working, he is watching nature documentaries or playing with his cats.

Leave a Comment



Nishant Das

January 17, 2022

I want to know how our blood works inside the our body


January 17, 2022

I feel yawn when i am tired


January 17, 2022

I feel tired? in daily life works so sometimes i yawn ?

Shashank Shekher

January 9, 2022

That’s excellent . The explanation was too good

Mohfiza Yeasmin Choudhury

January 8, 2022

I loved the concepts in byjus app . For its visualisation , it has become more interesting and also for such good and experienced teachers … Thankyou byjus…


January 7, 2022


Stuti Chatterjee

January 2, 2022

Thank you for the information. It was really nice and interesting.


December 31, 2021

How eye works

Divyanshi kumawat

December 28, 2021



December 26, 2021

Yawning is caused by insufficient oxygen in the body.

Mahima Maurya

December 26, 2021

Because of drawing more and more is stretch your brain with bi take a some nap for good availity to do the work and when you are not take any short nap you body feel just like yarn.
I think some short nap is good for our health and is also good for our brain if you are taking short nap your brain will be fresh and you did not feel any yawn . Show take some short nap that is beneficial for our body and be happy that good for our brain ?and he didn’t feel yarn when we are happy

I hope that is correct because I give the answer very fast and fast I have no more much and time to give the answer by the thinking more excitement thank you

Angel Mary Johnson

December 23, 2021

I accept the brain cooling theory…
I really enjoyed please make this type of more videos because when we watch it we feel more of exploring it and learn it
Thank you ..


December 22, 2021

Yes,I am also yawn sometimes when I am studying

Aarab Kumar Shaw

December 21, 2021

Because ham log ko nind aati hai

Bhoomija Bisht

December 19, 2021

There’s also a reason we yawn when our lungs are unable to function properly and basically there is a deficiency of oxygen our mouth automatically opens to take in air

Harshvardhan jain

December 16, 2021

Team byjus,
I personally think that we yawn when we are getting tired or bored but the most important thing to consider very particularly when we are relaxed…we yawn.
Relaxation is mainly connected with yawning
Thank you.


December 16, 2021

Why do we snore during asleep

Tanya Silelan

December 16, 2021

I loved the video?

Harshika chavan

December 15, 2021

Why are some people left handed ?

K .Tenshi Sunaina

December 15, 2021

One is that when we are bored or tired ,we just don’t breathe as deeply as we usually yawn. As this theory goes, our bodies take in less oxygen because our breathing has slowed. Therefore yawning helps us bring more oxygen into the blood and move more carbon dioxide out of the blood.


December 15, 2021

We have tears in our eyes while chopping Onions

zahra kapasi

December 15, 2021

i have 1 question
that is
why do tears come out of our eyes when we cut onions or come near onions


December 14, 2021

When we work hard we will tired and get sleep so yaw ing is a automatic action while We are in drousy mode

Ishan Dharmik sudheesh

December 14, 2021

OMG, this article is like reading my mind, I was mind blown when I read this: How many times have you yawned while reading this article? Well, yeah true I did yawn like 7 time or so

Aayush Aditeya

December 14, 2021

As you said
“Seeing someone else yawn – You are exposed to the same temperature as others”
But I also yawn when I see someone yawning virtually or on TV..
Why is that??????

Aayush Aditeya

December 14, 2021

I literally yawned ? 10 to 15 times while watching the video..
Great effort from Byjus, I understood why I yawn. Thank you byjus for one more awesome video. ?

Melon bread

December 13, 2021


Samma Khatoon

December 13, 2021

Good afternoon
I Also yawn at school, at tution because I had get up early morning for at 6 :30 and I have to do many work in entire day ( Going to school , going to tution , doing homework ,going for sports) and at sleeping at 10 ,11

Aryan Richhariya

December 13, 2021

Why warm water is coming outside from bore well In winter & cold water in summer ?

Aryan Richhariya

December 13, 2021

Do aquatic animal cry & laughs

Krish jani

December 12, 2021

Byju’s way of learning very well
Thank you so much.


December 12, 2021

why do we close our eyes while sneezing?

Aastha Pandey

December 11, 2021

I wanna ask a question why do we shiver when we feel cold ?????
And I absolutely love the Byju’s app and I’m now a premium member and my mentor is just amazing love Byju’s

Arpit Kumar

December 11, 2021

Tell me what happened if two cyclone collide ?


December 11, 2021


Swati Singh

December 11, 2021

It’s true, even I catched a yawn while watching this video. It is a very curious thing to be thought.


December 11, 2021

Really very easy to understand with interest.


December 11, 2021

Hii teachers


December 11, 2021

Yes i also yawn when i see anyone else yawning


December 11, 2021

Because our brain sences us that there is low oxygen in our body.

Yawns are not contagious.

Veerdhawal Amol Malve

December 11, 2021

Yes I had a yawn


December 11, 2021

I think 1 persent of world use their both hands

Parvathy A Preman

December 11, 2021

I think it’s the anaerobic respiration if our body wants to take rest.

Harsh indurkar

December 11, 2021

Why do we communicate each other

Siddhi Sharma

December 11, 2021

Why do we have such curiosity to know about anything new?


December 11, 2021

yawning helps us bring more oxygen into the blood and move more carbon dioxide out of the blood.


December 11, 2021

I sometimes while saying yawn in few movements we will yawn automatically .Thankyou


December 11, 2021

Why do we think ?

S. Naveena

December 11, 2021

My mentor Ekshuthan (from karnataka branch i think so)has been my pillar of strength from day one. It is her constant guidance and encouraging words that have helped me become a lifelong learner. A big thanks to her and BYJU’S – The Learning App.

Shreyansh saboo

December 11, 2021

This is interesting fact and this is also a knowledgeable fact .please make more video on fun fact.

Ch.Rushi Priya

December 11, 2021

Interesting topic
Good ????
In every point of view ur doing the best Byju’s ❤️

Utsa Barai

December 11, 2021

Really nice and help to know more

Sthiti Chakraborty

December 11, 2021

It was very helpful. I have a question, which makes me wonder a lot, that is why do we have hiccups? And why are we preferred to drink water to stop the hiccups?


December 10, 2021



December 10, 2021


Gokulavasan M

December 10, 2021

Byjus changed the way i see learning

Duksh Nath

December 10, 2021

We yawn because when we tired and board we don’t breath deeply and by yawning we take more oxygen and we can remove carbon dioxide .


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