Brennen McKenzie, MA, MSc, VMD

Did seeing that video make you yawn? If so, you just experienced one of the weirdest of human behaviors: the contagious yawn.

No one knows exactly what purpose yawning serves. We tend to do it more when we are sleepy or bored, and some scientists think it may help to make us feel more awake and attentive to our surroundings. Yawning might also affect the amount of oxygen in our blood, or help cool our brains when they get overheated. 

Other theories argue that yawning serves a social purpose rather than a biological one. It tells other people about our mood and helps coordinate social behavior in a group. As a teacher, I’ve certainly found it a useful signal to wrap things up when my students start passing a yawn around the room.

Humans are not the only animals to yawn. Fish, birds and mammals all yawn too. And of course, so do our favorite animals here at Loyal, dogs! 

Yawning in dogs may have the same physical functions as in humans, but the social purpose seems a bit different. Dogs do yawn before and after resting, suggesting yawns can signal sleepiness or help with waking up after a nap. However, yawning is also a well-known sign of stress and anxiety in dogs. They may yawn when nervous (like at the vet), or as a signal of appeasement- telling another dog or a human that they aren’t a threat. 

So what about contagious yawning? Humans often yawn when they see or hear, or even read about another person yawning. I have certainly yawned 

 while working on this post. But why do we do this? 

Research in humans suggests contagious yawning may be a sign of empathy, a reflection in our own behavior of how we sense another person is feeling. The more connected we are to someone, the more likely we are to catch their yawns. People catch yawns from family members or friends more than from strangers. And people who have more difficulty reading the feelings of others, such as children under five years old and people with some types of autism, appear to be less susceptible to contagious yawning. So what about other animals, including our canine companions? Do they experience contagious yawning? 

It won’t surprise you to learn that our closest evolutionary relative, the chimpanzee, exhibits contagious yawning. A few other primates do as well. Most other mammals don’t appear able to catch a yawn, but dogs are the exception. Dogs can catch yawns from other dogs, and from humans. Like us, they can catch a yawn in person or just from seeing or hearing one. And like humans, dogs are more likely to catch yawns from people or other dogs they know, suggesting that empathy plays a role in contagious yawning for dogs too. 

So the next time you yawn, take a peek and see if your dog does too!

If you want to dive deeper into the science of yawning, here are some articles to get you started.

Guggisberg, A. G., Mathis, J., Schnider, A., & Hess, C. W. (2010). 

Neuroscience & Biobehavioral Reviews, 34(8), 1267–1276. 

Yawning-Its anatomy, chemistry, role, and pathological considerations.

 Prog Neurobiol. 2018 Feb;161:61-78. doi: 10.1016/j.pneurobio.2017.11.003. Epub 2017 Nov 29. PMID: 29197651.

Norscia, I., Zanoli, A., Gamba, M., & Palagi, E. (2020). 

Auditory Contagious Yawning Is Highest Between Friends and Family Members: Support to the Emotional Bias Hypothesis

. In Frontiers in Psychology  (Vol. 11). 

Familiarity Bias and Physiological Responses in Contagious Yawning by Dogs Support Link to Empathy

Mouths wide open: Yawning as a communicative behavior in dogs. 

Master’s Thesis. Colorado State University, Fort, Collins, CO.

Can your dog catch your yawn?

<figure class="wp-block-image size-full"><img loading="lazy" decoding="async" width="498" height="280" src="https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/image5.gif" alt="" class="wp-image-124"/></figure>



Did seeing that video make you yawn? If so, you just experienced one of the weirdest of human behaviors: the contagious yawn.



No one knows exactly what purpose yawning serves. We tend to do it more when we are sleepy or bored, and some scientists think it may help to make us feel more awake and attentive to our surroundings. Yawning might also affect the amount of oxygen in our blood, or help cool our brains when they get overheated.&nbsp;



Other theories argue that yawning serves a social purpose rather than a biological one. It tells other people about our mood and helps coordinate social behavior in a group. As a teacher, I’ve certainly found it a useful signal to wrap things up when my students start passing a yawn around the room.



Humans are not the only animals to yawn. Fish, birds and mammals all yawn too. And of course, so do our favorite animals here at Loyal, dogs!&nbsp;



<figure class="wp-block-image size-large is-resized"><img loading="lazy" decoding="async" src="https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/image1-1-1024x683.jpeg" alt="" class="wp-image-125" width="643" height="429" srcset="https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/image1-1-1024x683.jpeg 1024w, https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/image1-1-300x200.jpeg 300w, https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/image1-1-768x512.jpeg 768w, https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/image1-1-1536x1024.jpeg 1536w, https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/image1-1.jpeg 1999w" sizes="(max-width: 643px) 100vw, 643px" /></figure>



Yawning in dogs may have the same physical functions as in humans, but the social purpose seems a bit different. Dogs do yawn before and after resting, suggesting yawns can signal sleepiness or help with waking up after a nap. However, yawning is also a well-known sign of stress and anxiety in dogs. They may yawn when nervous (like at the vet), or as a signal of appeasement- telling another dog or a human that they aren’t a threat.&nbsp;



So what about contagious yawning? Humans often yawn when they see or hear, or even read about another person yawning. I have certainly yawned a lot while working on this post. But why do we do this?&nbsp;



Research in humans suggests contagious yawning may be a sign of empathy, a reflection in our own behavior of how we sense another person is feeling. The more connected we are to someone, the more likely we are to catch their yawns. People catch yawns from family members or friends more than from strangers. And people who have more difficulty reading the feelings of others, such as children under five years old and people with some types of autism, appear to be less susceptible to contagious yawning. So what about other animals, including our canine companions? Do they experience contagious yawning?&nbsp;



<figure class="wp-block-image size-large is-resized"><img loading="lazy" decoding="async" src="https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/image2-1024x678.jpeg" alt="" class="wp-image-126" width="659" height="436" srcset="https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/image2-1024x678.jpeg 1024w, https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/image2-300x199.jpeg 300w, https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/image2-768x509.jpeg 768w, https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/image2-1536x1017.jpeg 1536w, https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/image2.jpeg 1999w" sizes="(max-width: 659px) 100vw, 659px" /></figure>



It won’t surprise you to learn that our closest evolutionary relative, the chimpanzee, exhibits contagious yawning. A few other primates do as well. Most other mammals don’t appear able to catch a yawn, but dogs are the exception. Dogs can catch yawns from other dogs, and from humans. Like us, they can catch a yawn in person or just from seeing or hearing one. And like humans, dogs are more likely to catch yawns from people or other dogs they know, suggesting that empathy plays a role in contagious yawning for dogs too.&nbsp;



So the next time you yawn, take a peek and see if your dog does too!







Learn More



If you want to dive deeper into the science of yawning, here are some articles to get you started.



Guggisberg, A. G., Mathis, J., Schnider, A., &amp; Hess, C. W. (2010). <a href="https://www.sciencedirect.com/science/article/abs/pii/S0149763410000825">Why do we yawn? </a>Neuroscience &amp; Biobehavioral Reviews, 34(8), 1267–1276.&nbsp;



Krestel H, Bassetti CL, Walusinski O. <a href="https://pubmed.ncbi.nlm.nih.gov/29197651/">Yawning-Its anatomy, chemistry, role, and pathological considerations.</a> Prog Neurobiol. 2018 Feb;161:61-78. doi: 10.1016/j.pneurobio.2017.11.003. Epub 2017 Nov 29. PMID: 29197651.



Norscia, I., Zanoli, A., Gamba, M., &amp; Palagi, E. (2020). <a href="https://www.frontiersin.org/articles/10.3389/fpsyg.2020.00442/full">Auditory Contagious Yawning Is Highest Between Friends and Family Members: Support to the Emotional Bias Hypothesis</a>. In Frontiers in Psychology&nbsp; (Vol. 11).&nbsp;



Romero T, Konno A, Hasegawa T (2013) <a href="https://doi.org/10.1371/journal.pone.0071365">Familiarity Bias and Physiological Responses in Contagious Yawning by Dogs Support Link to Empathy</a>. PLOS ONE 8(8): e71365.&nbsp;



Hoff, AE. (2001) <a href="https://mountainscholar.org/bitstream/handle/10217/39062/2001_Summer_Hoff_Anna.pdf?sequence=1&amp;isAllowed=y">Mouths wide open: Yawning as a communicative behavior in dogs. </a>Master’s Thesis. Colorado State University, Fort, Collins, CO.

Polls show 65-95% of people admit to regularly talking to their pets. And sometimes it really seems like they understand us. It’s pretty clear that they know what we mean when we say W-A-L-K or T-R-E-A-T! But do they really get more than that? How many words can they learn? Do they just know the names for things, or can they follow more complex phrases or even sentences? 

It is surprisingly difficult to clearly answer these questions. Dogs are exceptionally good at understanding humans; better than any animal outside our own species. But when we talk to them, we give a lot of information besides just words. Our gestures, facial expressions, posture, tone, and many other elements of our behavior carry meaning for our canine companions, and it is difficult to separate this from what they might understand from out words alone.

Some studies have tried to do this, and the results are impressive. Most dogs living in a home with humans probably understand 70-80 words that are regularly directed at them. They most commonly know their name, the names of toys and other valued objects, regular commands, and words for other things of special significance, like “walk” and “park.” 

Some dogs with extensive training can do a lot more. A border collie named Chaser was shown to understand over 1,000 words, and to be able to understand new combinations of these words. For example, once taught that “touch” means to touch an object with her nose, she could direct this behavior at objects she had never touched before once she knew what the object is called. Importantly, she could do this based on spoken words only, without being able to see the human giving the commands, which reduces the chance that she might have been responding to other cues. This is an impressive level of comprehension that takes even human children more than a year of growth and development to begin mastering!

Of course, language doesn’t come as naturally to dogs as humans, and they certainly don’t ever approach our level of comprehension. The average human without any special training routinely uses about 20,000 words and can comprehend more than 40,000, and we use language in incredibly complex and creative ways. So your dog may not really get the nuances when you tell her about your recent breakup or your tough day at work. But fortunately, she’ll listen and support you anyway, because dogs are awesome!

For a closer look at some studies of what dogs can do with human language, check out these articles.

Responses to spoken words by domestic dogs: A new instrument for use with dog owners.

 Applied Animal Behaviour Science. Volume 246, 2022, 

https://doi.org/10.1016/j.applanim.2021.105513

John W. Pilley, Alliston K. Reid. Border collie comprehends object names as verbal referents. Behavioural Processes. Volume 86, Issue 2, 2011. 

https://doi.org/10.1016/j.beproc.2010.11.007

Talking to your dog?

Polls show 65-95% of people admit to regularly talking to their pets. And sometimes it really seems like they understand us. It’s pretty clear that they know what we mean when we say W-A-L-K or T-R-E-A-T! But do they really get more than that? How many words can they learn? Do they just know the names for things, or can they follow more complex phrases or even sentences?&nbsp;



It is surprisingly difficult to clearly answer these questions. Dogs are exceptionally good at understanding humans; better than any animal outside our own species. But when we talk to them, we give a lot of information besides just words. Our gestures, facial expressions, posture, tone, and many other elements of our behavior carry meaning for our canine companions, and it is difficult to separate this from what they might understand from out words alone.



Some studies have tried to do this, and the results are impressive. Most dogs living in a home with humans probably understand 70-80 words that are regularly directed at them. They most commonly know their name, the names of toys and other valued objects, regular commands, and words for other things of special significance, like “walk” and “park.”&nbsp;



Some dogs with extensive training can do a lot more. A border collie named Chaser was shown to understand over 1,000 words, and to be able to understand new combinations of these words. For example, once taught that “touch” means to touch an object with her nose, she could direct this behavior at objects she had never touched before once she knew what the object is called. Importantly, she could do this based on spoken words only, without being able to see the human giving the commands, which reduces the chance that she might have been responding to other cues. This is an impressive level of comprehension that takes even human children more than a year of growth and development to begin mastering!



Of course, language doesn’t come as naturally to dogs as humans, and they certainly don’t ever approach our level of comprehension. The average human without any special training routinely uses about 20,000 words and can comprehend more than 40,000, and we use language in incredibly complex and creative ways. So your dog may not really get the nuances when you tell her about your recent breakup or your tough day at work. But fortunately, she’ll listen and support you anyway, because dogs are awesome!







Learn More



For a closer look at some studies of what dogs can do with human language, check out these articles.



Catherine Reeve, Sophie Jacques. <a href="https://www.sciencedirect.com/science/article/pii/S0168159121003002#bib39">Responses to spoken words by domestic dogs: A new instrument for use with dog owners.</a> Applied Animal Behaviour Science. Volume 246, 2022, <a href="https://doi.org/10.1016/j.applanim.2021.105513">https://doi.org/10.1016/j.applanim.2021.105513</a>



John W. Pilley, Alliston K. Reid. Border collie comprehends object names as verbal referents. Behavioural Processes. Volume 86, Issue 2, 2011. <a href="https://doi.org/10.1016/j.beproc.2010.11.007">https://doi.org/10.1016/j.beproc.2010.11.007</a>.



(discussed briefly in <a href="https://www.usatoday.com/story/news/nation/2013/11/24/smart-dog-border-collie-learns-language-grammar/3691967/">this USA Today article</a> or in depth <a href="https://www.amazon.com/Chaser-Unlocking-Genius-Knows-Thousand/dp/0544334590">in this book</a>)

I’m often amazed by how sensitive my dog Brodie is to my mood. When I’m feeling happy or acting in any way playful with the other humans in our house, Brodie races over with a big smile, and usually a toy for me to pull on.

On the other hand, if I’m angry or a little sad, Brodie is more likely to offer me his cute “sad face” and a lick or two (common among dogs as a gesture of appeasement).

He even seems to know when I’ve been working too long and need a puppy break!

Clearly, our dogs are really good at knowing what we’re feeling and responding accordingly. But how do they do it? What gives us away? The answer is a fascinating look into the world of cross-species communication.

Dogs are both like us and very different. Like humans, they are highly social, and their ancestors evolved sophisticated systems for communicating amongst themselves long before the first wolves wandered over to one of our campfires. Part of the reason they were so successfully domesticated is that they were already shaped by a social environment very similar to our own, and they were good at communicating and reading emotional cues.

But of course, dogs and humans are different too. We use language and our faces to do most of our talking, while dogs make much more use of body posture, ear and tail position, and even scent. I’m the first to admit Brodie has a cute and expressive face, but he can’t match a human for the sheer number of facial muscles (about 30-40, depending on how you count them) and distinct facial expressions (hundreds at least, maybe thousands). 

Given that dogs are great at reading emotions but are built quite differently from humans in how they express their feelings, how do they do at reading human faces? It turns out, pretty darn well (though again, not as well as another human would). Several scientific studies have found that dogs can recognize individual humans and that they can distinguish between basic facial expressions, such as anger or happiness, just by facial features. They can even identify happy or sad faces when they only see part of the face, so we know they can isolate features, like eyebrows and mouths, and recognize the way these features each look as part of an overall expression of one emotion. 

Dogs do run into some limitations when reading our faces, though. Some studies find that dogs are better at reading the expressions of their owners, and they can get confused when looking at a stranger, especially a person of a different gender. And while they can distinguish different facial expressions, it isn’t entirely clear if they know what each one means. They seem to prefer happy faces to sad ones, which suggests they might be able to understand who is likely to give them a treat and who might be more likely to yell “Bad dog!” at them. But they probably can’t recognize wistful nostalgia or a “just kidding” wink and nod. 

Despite these limitations, though, dogs have a lot of other ways to figure out what their humans are feeling. Our posture and movements, tone and volume, and even the 

 probably help a lot in making our dogs the super sensitive readers of human emotion they are. After all, for most of them, figuring out what mood we are in is crucial to doing their job. Brodie isn’t going to be chasing off any predators or bringing me some wild-caught dinner any time soon, but he does a great job at being a playmate and a source of comfort when I need it!

Check out some of these clever studies looking at what dogs can understand about human faces. The last one is also a cool insight into how domestication has changed the anatomy of dogs to make their own faces more expressive!

Racca A, Guo K, Meints K, Mills DS (2012) 

Reading Faces: Differential Lateral Gaze Bias in Processing Canine and Human Facial Expressions in Dogs and 4-Year-Old Children

Corsin A. Müller, Kira Schmitt, Anjuli L.A. Barber, Ludwig Huber. 

Dogs Can Discriminate Emotional Expressions of Human Faces.

 Current Biology. Volume 25, Issue 5:2015. 

https://doi.org/10.1016/j.cub.2014.12.055

Kaminski J, Waller BM, Diogo R, Hartstone-Rose A, Burrows AM. 

Evolution of facial muscle anatomy in dogs.

 Proc Natl Acad Sci U S A. 2019 Jul 16;116(29):14677-14681. doi: 10.1073/pnas.1820653116. Epub 2019 Jun 17. PMID: 31209036; PMCID: PMC6642381.

Yes, dogs really can read facial expressions

I’m often amazed by how sensitive my dog Brodie is to my mood. When I’m feeling happy or acting in any way playful with the other humans in our house, Brodie races over with a big smile, and usually a toy for me to pull on.



<figure class="wp-block-image size-full"><img loading="lazy" decoding="async" width="386" height="542" src="https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/brody1.jpg" alt="" class="wp-image-113" srcset="https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/brody1.jpg 386w, https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/brody1-214x300.jpg 214w" sizes="(max-width: 386px) 100vw, 386px" /></figure>



On the other hand, if I’m angry or a little sad, Brodie is more likely to offer me his cute “sad face” and a lick or two (common among dogs as a gesture of appeasement).



<figure class="wp-block-image size-full"><img loading="lazy" decoding="async" width="378" height="418" src="https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/brody2.jpg" alt="" class="wp-image-114" srcset="https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/brody2.jpg 378w, https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/brody2-271x300.jpg 271w" sizes="(max-width: 378px) 100vw, 378px" /></figure>



He even seems to know when I’ve been working too long and need a puppy break!



<figure class="wp-block-image size-full"><img loading="lazy" decoding="async" width="592" height="392" src="https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/brody3.jpg" alt="" class="wp-image-115" srcset="https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/brody3.jpg 592w, https://blog-admin.loyalfordogs.com/wp-content/uploads/2022/03/brody3-300x199.jpg 300w" sizes="(max-width: 592px) 100vw, 592px" /></figure>



Clearly, our dogs are really good at knowing what we’re feeling and responding accordingly. But how do they do it? What gives us away? The answer is a fascinating look into the world of cross-species communication.



Dogs are both like us and very different. Like humans, they are highly social, and their ancestors evolved sophisticated systems for communicating amongst themselves long before the first wolves wandered over to one of our campfires. Part of the reason they were so successfully domesticated is that they were already shaped by a social environment very similar to our own, and they were good at communicating and reading emotional cues.



But of course, dogs and humans are different too. We use language and our faces to do most of our talking, while dogs make much more use of body posture, ear and tail position, and even scent. I’m the first to admit Brodie has a cute and expressive face, but he can’t match a human for the sheer number of facial muscles (about 30-40, depending on how you count them) and distinct facial expressions (hundreds at least, maybe thousands).&nbsp;



Given that dogs are great at reading emotions but are built quite differently from humans in how they express their feelings, how do they do at reading human faces? It turns out, pretty darn well (though again, not as well as another human would). Several scientific studies have found that dogs can recognize individual humans and that they can distinguish between basic facial expressions, such as anger or happiness, just by facial features. They can even identify happy or sad faces when they only see part of the face, so we know they can isolate features, like eyebrows and mouths, and recognize the way these features each look as part of an overall expression of one emotion.&nbsp;



Dogs do run into some limitations when reading our faces, though. Some studies find that dogs are better at reading the expressions of their owners, and they can get confused when looking at a stranger, especially a person of a different gender. And while they can distinguish different facial expressions, it isn’t entirely clear if they know what each one means. They seem to prefer happy faces to sad ones, which suggests they might be able to understand who is likely to give them a treat and who might be more likely to yell “Bad dog!” at them. But they probably can’t recognize wistful nostalgia or a “just kidding” wink and nod.&nbsp;



Despite these limitations, though, dogs have a lot of other ways to figure out what their humans are feeling. Our posture and movements, tone and volume, and even the <a href="https://blog-admin.loyalfordogs.com/talking-to-your-dog/">words we say</a> probably help a lot in making our dogs the super sensitive readers of human emotion they are. After all, for most of them, figuring out what mood we are in is crucial to doing their job. Brodie isn’t going to be chasing off any predators or bringing me some wild-caught dinner any time soon, but he does a great job at being a playmate and a source of comfort when I need it!







Learn More



Check out some of these clever studies looking at what dogs can understand about human faces. The last one is also a cool insight into how domestication has changed the anatomy of dogs to make their own faces more expressive!



Racca A, Guo K, Meints K, Mills DS (2012) <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0036076">Reading Faces: Differential Lateral Gaze Bias in Processing Canine and Human Facial Expressions in Dogs and 4-Year-Old Children</a>. PLoS ONE 7(4): e36076.&nbsp;



Corsin&nbsp;A. Müller, Kira Schmitt, Anjuli&nbsp;L.A. Barber, Ludwig Huber. <a href="https://www.cell.com/action/showPdf?pii=S0960-9822%2814%2901693-5">Dogs Can Discriminate Emotional Expressions of Human Faces.</a> Current Biology. Volume 25, Issue 5:2015. <a href="https://doi.org/10.1016/j.cub.2014.12.055" rel="nofollow">https://doi.org/10.1016/j.cub.2014.12.055</a>.



Kaminski J, Waller BM, Diogo R, Hartstone-Rose A, Burrows AM. <a href="https://www.pnas.org/doi/10.1073/pnas.1820653116">Evolution of facial muscle anatomy in dogs.</a> Proc Natl Acad Sci U S A. 2019 Jul 16;116(29):14677-14681. doi: 10.1073/pnas.1820653116. Epub 2019 Jun 17. PMID: 31209036; PMCID: PMC6642381.