Do Dogs Know When Humans Are Sleeping? (Answered By Trainer)

do laying quietly because he's aware that his owner is sleeping

Dogs have claimed and maintained the “man’s best friend” spot for centuries, being by our side and ready for anything! And if you have a loyal pooch (which you probably do), then chances are they’ll do anything to keep you safe.

This may sound either creepy or adoring to you, but it is completely natural for your pup to want to be your security guard. And at night, even if you think that they’re sleeping too, they will still have one eye open for any danger that tries to come your way!

If you think that some dogs don’t have a watchdog bone in their body, you never know what happens at night (for all you know, they could be a superhero, fighting crime while you snooze until the morning!)

OK, maybe he isn’t wearing a cape and being that kind of protector. But our dogs are smart enough to register when their humans are sleeping! And with this knowledge and some diligence, our pups are able to make sure nothing bad occurs while you get some well-deserved rest.

So, how do dogs even know when their human is sleeping?

Dogs know when humans are sleeping by using their senses of sight, touch, smell, and hearing to notice subtle shifts in muscle movements, breathing patterns, involuntary behaviors, and even hormone changes coming from our breath. Your individual habits help your dog too as he will learn what is specific to you and your sleep cycle! 

Dogs manage to impress us every day with their advanced senses, and it is just like our selfless companions to use sensory cues to learn more about us!

Let’s dive into the four senses and how our pups utilize them to determine when we are asleep versus awake. Within each sense, we will talk about the physical (and sometimes chemical) cues they pick up on by using either their sight, touch, smell, or hearing!

The Four Senses Dogs Use To Know When Humans Are Sleeping

Let’s break them down one at a time!


Our canines have outstanding senses, and their sight is far better during the nighttime than ours could ever be!

Dogs can see impressively well in the dark thanks to their evolutionary history. Wolves are known to be either nocturnal or crepuscular (active at dawn and dusk) hunters, so they had to be equipped to see in minimal-light situations if they wanted to eat and survive.

Research shows that the dog has a larger lens and corneal surface compared to humans, letting them capture more light. And if you’ve ever seen your dog’s eyes glow yellow, orange, or green in the dark when recording him with the flash, you can thank the tapetal area for that! The tapetum lucidum was studied in 1983 and found that in dogs, it is located in the dorsal fundus behind the retina. It lets your pup reflect the light back to your retinal cells for a second chance at stimulation, which results in greater low-light visual sensitivity.

Check out this video for further learning about what experts suggest a dog sees:

So, even when it is seemingly pitch black, your dog can see fine!

This crafty evolutionary trick allows your dog to watch you when you’re getting into bed and yes- when you are sleeping! And when you are asleep, your breathing habits change involuntarily as you go through cycles. A study recorded the average adult to breathe 12-20 times per minute in deep sleep, and your pup can pick up on your individual breathing patterns and begin to associate the differences with either being awake or bedtime!

Dogs also observe the kinds of bodily movements you do at night. Your shut eyes will be the first indication, and the eye’s rapid movement in REM sleep will let your pup know that you aren’t exactly conscious at the moment. Some people are motionless sleepers, while others (myself included) kick and tumble the night away! Once they see you lay in bed for the whole night a few times, they’ll start learning that those movements correlate with you being asleep during this time. Your actions will be their instant cue that you are resting and they are on watch duty!

Watching your chest rise and fall along with the amount of physical activity you do at night, your dog will associate these behaviors with sleeping and know to hopefully leave you alone until the morning!


This sense will be used by your dog if you leave him out in the home for the night or if he sleeps in bed with you. Obviously, he can’t touch you to determine your consciousness if he’s inside his crate; rather, he will use his other senses to learn this!

But, if your dog free roams, then expect him to use touch to help him learn when you are actually sleeping.

Your dog will stay by your side at night for a number of reasons, whether they want to protect you, they sense illness, they love you- the list goes on!

If your pooch really loves when you are awake, don’t be surprised if they come to lay by you when the sun starts to come up! Touching you is an easy way for them to feel your body come out of deep sleep since you will start moving more and have increased muscle tension overall. They want to be the first thing you see when you open your eyes!

Even if they lay by your side all night and sleep while you sleep, they will still wake up if you make sudden, tiny movements that aren’t normal for you.

This is because our pups still carry certain traits from wolves, where they become alert quickly upon waking if danger is sensed. Yes, this even applies to our extra sleepy breeds out there! Research has been done comparing wolves and domesticated dogs before, and one interesting study revealed our dogs may actually be more alert than their ancestral counterparts! This is likely due to their individual diligence in protecting their “pack leader” and meeting demands (AKA all for you).

Your pup looking to protect you while you rest is adorable, and the science behind it is fascinating! We know how quickly dogs learn and mimic certain behaviors from their owner, so it is expected that they will also come to know when you’re sleeping and in need of safeguarding with the help of some touch!


Some dog breeds have been historically used for their heightened sense of smell, though this does not mean other breeds don’t have a good sniffer on them. This actually couldn’t be further from the truth!

Often-used research has found that a dog’s sense of smell is 10,000-100,000 times more acute than a human’s! Almost unreal to think about, but it makes sense why dogs have a plethora of jobs that help humans every day.

It is normal for your pup to sniff your breath, and there are many reasons why they may do this! While smelling your breath while you’re asleep might sound a bit disturbing (or disturbing at any point throughout the day), it is your dog’s way of checking to see if you’re actually sleeping or just resting and ignoring their plea for pets.

But how do they do this?

Your breath has a variety of hormone scents, a few being melatonin, growth hormones, and cortisol. The pineal gland triggers the release of melatonin when it gets dark outside (making you and your pup sleepy), and your pooch can smell this from you when it is bedtime.

Growth hormones are secreted at differing levels throughout sleep and contribute to decreasing wakefulness. This is likely what your pup will smell in the middle of the night when they lean over to you. Lastly, cortisol can be sensed on your breath in the morning when you are closer to waking, as an area in your brain (suprachiasmatic nucleus) triggers the release of cortisol when the sun comes up to help wake the body.

So, your pooch may sniff your breath and learn what is normal for it to smell like from the moment you go to sleep to the moment you wake. They will come to understand your body’s complex chemical patterns, and easily sniff out your sleep progress.

And with their incredible sense of smell, they don’t even have to be next to your mouth to be able to smell the breath coming from you. They can be across the room and still know if you are sleeping based on your hormones and their amazing sniffer!


Another superpower of dogs: their hearing!

The fascinating anatomy of the canine ear allows our pooches to both hear and maintain their balance. And their range of sound is no joke; they hear best at 8,000 Hz (humans only hear best at 2,000 Hz), and studies reveal that they can hear upwards of 67,000 Hz!

Any slight rustling of your bedsheets or pillow in the morning will be heard by your dog, whether they are in the kitchen, upstairs, or right by your bed. If you wake up and stretch, your dog is going to hear it no matter what. If you wake up and think you’re quiet as a mouse, your dog will still hear you and probably come running over.

Sometimes, they will come over to you before you even wake up, as humans tend to start moving more the closer we get to the end of our sleep cycle. Our dog’s hearing is four times more sensitive than a human’s, so nothing will slip by them!

To top it off, a study was done that shows both big and small breed dogs are receptive to the same frequencies, leaving no size out of determining what you are up to at night and learning to hear your sleeping patterns. Your Great Dane and Pomeranian will listen to you just as effectively as one another!

As with looking at you, your dog can also hear the shift in your breathing pattern throughout the night. Once your breathing becomes more irregular and quicker (which is an involuntary body function), it is to their knowledge that you will be waking up to play soon!

It doesn’t take long for your pup to learn what your patterns of sleep are since they pick up this mix of sensory cues and combine it to figure out what is happening around them and you. Especially if you use an alarm clock, your dog is sure to learn the pattern of when the alarm is blaring and you aren’t sleeping anymore! I love talking about Pavlov and his experiments stumbling upon classical conditioning because it really influences your dog’s behavior and how they react to certain stimulus.

Dogs are all-stars, and a combination of their exceptional hearing and quick learning will allow them to know exactly when their owners are sleeping and when they’re awake, ready to be bombarded with love.

Closing Thoughts

Humans are beaten by dogs when it comes to the five senses and their skills. Dogs are complex organisms, and it is exciting to learn about new research every year that delves into their capabilities that we could only dream of having!

While having your dog watch you while you sleep is creepy for some, I think it is a beautiful way for nature to connect us to our furry friends even further. They want to learn when you are sleeping and what it looks like, so they can feel more involved in your life and protect you!

And it is quite simple for your pup to actually learn when you are asleep, using sight to watch your breathing patterns, eye and body movements, and touch to feel increased muscle tension and abnormal motions. Hearing allows them to keep track of any bedsheets moving and breathing tempo changes when it gets closer to morning. Smelling various hormones that your body secretes will help your pup learn the timeline of your sleep cycle from when you fall asleep to when you wake up!

It is an understatement to say these abilities for dogs are magnificent, and it makes them efficient at truly understanding our need for a beauty snooze each night. Dogs are intelligent, so be sure to give them credit where it’s due!

Most of the time your pooch will join you in sleeping through the night, but remember, they are always watching!

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