Ask Doggy Dan AI About Your Dog Now  🐶
Dan's AI Chat Widget

Why Dogs Have Sensitive Smell: The Science Behind

dog training to build a strong bond and better behavior.

Last Updated: October 2025

Last updated: October 2025

The-Science-behind-a-Dogs-Incredible-Sense-of-Smell-HEADLINE-IMAGE

Do you ever wonder why your dog’s nose is always running a mile a minute?

The answer is simple: A dog’s sense of smell is his most powerful sense.

A dog can use his nose to sniff out food, his friends, and danger from miles away. So, even when we can’t smell anything around, it’s possible that your pup is in the middle of smelling something amazing!

While it’s common knowledge that dogs can smell really well, the science behind why they can smell for miles or what they use their sense of smell for isn’t always discussed.

Today, I thought it would be fun to talk about the science AND instinctual behavior behind why dogs are always smelling stuff.

But first let me point out that, if you’re struggling with a hyper-obsessive sniffer who can’t calm down and you haven’t put my foundation program The Dog Calming Code in place yet, then that is the first thing you should do after reading this.

(Or, if you have a puppy my Puppy Coach training program might be a good place to start!)

It’s sure to be the simplest way to calm your dog’s obsessive sniffing!

Okay…let’s get started…

Why Dogs Have an Incredible Sense of Smell

Dogs have relied on their noses for centuries to sniff out water, food, and predators.

Therefore, from a biological standpoint, it makes sense that a dog's nose would be designed to be far more powerful than a human nose.

But, how much more powerful?

The Marcach Road Animal Hospital tells us that…

“While humans possess only about 6 million smell receptors, our canine friends can have up to 300 million. But, that’s not the only difference. The part of the brain dedicated to processing smells is also 40 percent larger in a canine than in a human brain.”

That’s not the only unique thing about a dog's nose though.

Many people don’t know that dogs actually have an extra organ that humans don’t.

It’s called the Jacobson’s organ.

According to Cuteness.com

“The Jacobson’s organ is located at the bottom of the dog's nasal passage and allows dogs to pick up on pheromones—important chemical cues all animals produce that signal messages to one another, like mating readiness.”

The Jacobson's organ is also important for dogs recognizing the scent of other dogs in their pack or puppies locating a nipple to nurse. If a dog is trying to get more scent to his Jacobson's organ, he may pull back his upper lip and rear back his head — called the “flehmen” reaction.”

How Dogs Use Their Noses

By now you understand the science behind why dogs can smell so well—and for good reason.

Without a powerful nose, it would be hard for dogs to find meals and protect themselves in the wild.

That being said, most pet dogs don’t need to resort to using their nose to sniff out their next meal.

For that reason, we thought it would be fun to take a look at how dogs use their nose and explain why dogs seem to enjoy smelling funny things like trash and butts.

Let’s start with a common one that grosses a lot of people out…butts.

Why Dogs Sniff Butts

As humans, a friendly handshake or a hug is the politest way to greet a new (or old) friend.

For a dog, the go-to “nice to meet you” greeting is butt sniffing.

As humans, we find this strange or amusing and often try to pull our dogs away from each other when this type of greeting occurs.

But, a formal butt sniffing is actually really important for dogs.

Mentalfloss.com tells us that…

“When one dog greets another with a nose in the derrière, it’s basically getting a brief biography of its new friend, written in scent molecules and pheromones.

To the sides of a dog’s butt are pouches called anal sacs; these contain glands which secrete chemicals that can tell a sniffer a lot of information about their owner, like gender, reproductive status, and clues about its health, diet, and even emotional state.

It may seem like a strange way to go about it, but butt sniffing is just the canine version of shaking hands and introducing yourself.”

The next time you’re out and about with your dog and he tries to “greet” a friend, let him do so. It’s a very important part of a dog's social greeting.

Why Dogs Love the Smell of Trash and Rotting Materials

Because a dog's nose is so powerful, you’d think your canine companion would stay far away from odors such as trash or decomposing dead animals.

Yet, the exact opposite is true.

Just think about how many times your dog has gotten into your trash bin. Or, how many times Fido has stopped your walk in the park to roll over a dead frog or something else stinky.

So, why do dogs do this?

Psychology Today has some great insights as to why dogs do this. Here’s what they had to say…

“Since the wild ancestors of dogs were not only hunters but also scavengers, much of the stuff that they are rolling in could still possibly be edible.

The notion then is that the wild canine rolls in this material and then returns to the pack. The other members of his group immediately pick up this scent and know that there is something which can pass for food nearby.

Another theory suggests that the dog is not trying to pick up odors from the stinking mess it rolls in, but is actually trying to cover that smell with their own scent.
It is certainly true that dogs and wolves will often roll around on something, like a stick, a new dog bed or such, as if they were trying to deposit their scent on it.

Some psychologists have suggested that dogs often rub against people to leave a trace of their scent and to mark the individual as a member of the pack, much the way that cats rub up against people to mark them with their odors.”

We still don’t 100% know why this is true. But, I would imagine the behavior is derived from a handful of different safety or pack-related habits.

Why Dogs Are Constantly Smelling Their Owners

Last but not least, I want to talk about why your dog may often give you a sniff.

First and foremost, you’re a part of your dog's pack. For this reason, it’s important that your dog has your scent in the event that something would happen to you.

Smell is very important for identification. In fact, a blind dog can easily identify who different people are through the sense of smell.

Aside from identification, we’ve discovered in the last few decades how much dogs use their sense of smell to gauge health.

For example, a dog can smell bacteria.

In the wild, dogs can tell who is healthy and who is unwell in the pack by simply sniffing each other.

This process helps with the pecking order as weaker, older, and sicker dogs are usually kept in the middle of the pack while in transit.

Today, we can use this powerful instinct to train dogs to sniff health issues in humans, such as…

  • Cancer cells
  • Low blood sugar levels
  • Diabetes
  • Chemical changes that cause seizures
  • Infections
  • And more!

Dogs are amazing animals, and with super-powered noses, they’ve been helping us save lives—whether it be in hospitals or on the battlefield—for many years.

The good news—we can use a dog's sense of smell to help them enjoy life and relax too.

In fact, if you have a dog that’s always anxious or stressed out, essential oils can be used to help him safely and naturally relax and unwind.

(Just remember to check out my foundation program The Dog Calming Code OR my Puppy Coach training program for puppies before you do anything else.)

So, if you’re interested in learning how to use smell to settle down an anxious or stressed-out dog, I encourage you to download my FREE guide to 3 Smells That Naturally Calm and Relax Dogs.

In this guide, I’ll share 3 essential oils that have been proven to calm dogs as well as info on how to safely diffuse these oils in your home.

You may also find the oils calm you down, which, in return, will relax your dog!

Get your FREE guide here!

Cheers,

Doggy Dan Signature
~Doggy Dan 🙂

Gentle journey for your puppy.

Doggy Dan

Doggy Dan stands out through his “five golden rules” that focus on canine psychology rather than repetitive drills or force. Unlike traditional trainers, he teaches owners to become the “calm leader” their dogs need. Over the last two decades, his methods have helped transform over 125,000 dogs worldwide. As the founder of TheOnlineDogTrainer.com blog and podcast and creator of the Dog Calming Code™, he has become a trusted voice in dog psychology and training. His philosophy is simple: reactive dogs don’t need punishment or endless treats. They need a leader they can trust.

6 Responses

  1. Hello Doggy Dan.
    Thanks for helping me raise my (now 10 month old) toy poodle. Our life wouldn’t be the same without you … hahah!!

    Suki loves eating mud and won’t let a good hole go to waste. She follows this with a second course of sticks of any sort. This really worries me. Is there anything I can do to stop her?

    BTW: Pumpkin (cooked) is a terrific remedy for dogs eating poop.

    Thanks

    1. Sometimes this is diet related. Check out my podcast show about raw feeding. Dr Susan Thixon is a great place to start

    1. Hi,
      There are a few reasons that dogs eat their own and other animals poo. Believe it or not they may derive some nutritional benefit from eating poo, and it can be a sign that they have a deficiency in their own diet. Some dog also just really like eating poo! Unfortunately, there’s not much you can do to curb this behavior aside from keeping your dog away from other animal droppings. Although one very popular tip is to feed your dog a little bit of pineapple! Yep, that’s right. A bit of pineapple may do the trick in stopping them from eating their own faeces. Best, Doggy Dan

  2. Hi Dan, I found your site because someone posted your harmonium video on a dog group I belong to. I love your site. One comment though on the article about “Why dogs sniff that?” is that you mention using essential oils with dogs. You do not specify in the article that many essential oils are toxic to dogs (and cats), and that people need to learn exactly which oils are safe. Someone who doesn’t know that or take the time to do their research first may inadvertently poison their animal thinking that all essential oils are safe based on that comment. It might be helpful to let people know that many oils are quite toxic to dogs and cats. Thanks and have a blessed day.

    1. Thanks Renee, this is a really good point! Knowing which foods, plants, chemicals (etc) may be harmful for our pets is very important…essential oils included. The internet is such a helpful tool in this area and a quick search will allow owners to discover if the essential oil they are using may be a problem for their dog..or cat! Best, Doggy Dan

FREE TRAINING:

How to Solve Dog Reactivity WITHOUT Food Bribes, Tricks, or Force

Limited spaces!

FREE webinar:

How to Solve Dog Reactivity WITHOUT Food Bribes, Tricks, or Force

dog training to stop unwanted jumping and barking

Limited Spaces!

Recent Posts

Excellent rating
Based on 156 reviews
Google star 1Google star 2Google star 3Google star 4Google star 5
Google star 1Google star 2Google star 3Google star 4Google star 5
+0
Ridley is my 4th dog. After listening to and learning from Doggy Dan, I was happy to see that I did pretty well with my first 3 dogs while raising my kids and having my husband with me. Not perfect - but pretty good! Now I am raising a new dog by myself, and I feel like I'm not doing this really "alone." I really am so happy with all the information Dan has offered... and all his techniques work well!!
Carol Ann Ferrari Rogers profile picture
Carol Ann Ferrari Rogers
21 September 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
Two months ago I adopted a 7 year old Morkie, a very nervous but loving little fellow. I tried several different training techniques and even purchased a program that was lengthy and very time consuming before I discovered Doggy Dan. I've been using his program for two weeks and am astounded by the change in my Dexter. He is calmer, more obedient and friendlier to others than I imagined possible. Dan's training is concise. It differs from others I found, Dan trains you to become the leader of your pack through a dog's perspective. I like that the training is specific yet compassionate. This is a program that works if you are consistent. Thanks Doggy Dan!
Kathy Fore profile picture
Kathy Fore
17 September 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
+0
Susie in the UK. I am only 10 days in but took in a 9 yr old emergency rescue from Romania who had been in kennels for 6 years and then had 3 failed foster placements in the UK. Luca is a big powerful mixed breed with huge stress and anxiety and very reactive, he bounded into my home and took over - aggressive with my 2 others, and visitors and pulling and pushing on walks. I thought I couldn't handle him but saw an advert for Doggy Dan on line and signed up - we've had a wonderful turnaround and he is finally decompressing, being polite with my dogs and responds excellently to the time-out if reactive with guests. Walks are much better and all 5 rules are in place. I believe he will continue to improve but only if I remain 100% consistent with him for the rest of his life. He is 9 years old and deserves a happy old age being loved and looked after with no further upsets in his life so fingers and toes are crossed for him
SoBS Truro profile picture
SoBS Truro
15 September 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
+2
I started. The course 3/4 weeks ago. As Dan says you have to work on things if you get stuck. I have a Staffordshire x cane corso who is now six months old. She is very intelligent but sometimes she just doesn’t listen. Doing the five codes I’m finding it’s going pretty well except trying to get her calm so I am persevering with it again with my own space. I have a trainer call shortly which I will ask for advice on this. It’s great also that you can ask anything you’re not sure of on line. It’s so great to have someone there to help. I’m looking forward to having a relaxed girl instead of hyper most of the time as she gets so excited about almost everything. I would truly recommend doggy Dan and just wished I would have come across him much earlier. Thanks again for everything so far.
Hazel Coad profile picture
Hazel Coad
12 September 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
I ❤️ my dog. Such a good girl! 5 Golden rules, really work.
Victoria van Sommeren profile picture
Victoria van Sommeren
9 September 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
+0
This program is amazing!. We have a VERY reactive rescue dog that has bitten his previous owner and as well, myself 3x and my husband 4 x's. He had never been around people or other animals, and had never been walked on a leash. (in fact never run off-leash either, just tied to the front steps). We began with traditional treat-based training with a professional, but the progress was frustrating. A reactive dog does not want treats; it wants comfort. With the 5 Golden Rules and and some of the other training we have received with our subscription, in just 3 weeks, we can let him off leash at the dog park, he has not growled at any stranger, and he has not attacked any other animals. He is still a work in progress, but we see progress!!!! He has become a cuddly, sweet dog and for a greyhound, he even has recall! This program is amazing to say the least. We were at our wits end, but now we have hope.
susan kent profile picture
susan kent
8 September 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
Okay, he says it’s not magic, but the results and the peace in so little time with so little effort sure feels like magic! My 11 month old pup was a 60lb highly reactive, very loud disaster waiting to happen. Now we are both calm, the house is quiet and I don’t live in absolute fear of his reactivity towards others. There’s always still work/training to do of course, but wow are we in a much better place to get on with that!
Theresia Travers profile picture
Theresia Travers
8 September 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
Just started with the 5 rules. It's only been a week and a half and I'm noticing less stress, and a reduction in reactivity. We still have a way to go. But finally something I can work with. I went for the online course.
Fiona Bower profile picture
Fiona Bower
31 August 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
I watched the free Webinar and joined at the end. I am up to No.3 atm and I’m actually feeling hopeful 🤞🏼
Jackie Grimmer profile picture
Jackie Grimmer
29 August 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
The program is great. I started to see the changes in my cocker spaniel from day one.
Joy Winnington profile picture
Joy Winnington
18 August 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
+3
My Lab mix puppy and I are on Day 3 , but, I do feel a stronger connection. She appears calmer overall / looking forward to consistently following these five rules. Doggy Dan is clear, concise, comprehensive and compassionate . Very pleased with his program. Diane
Diane Patterson profile picture
Diane Patterson
16 August 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
+0
We have an 8 month old Goldendoodle who has fear issues outside the home and gets easily overwhelmed going into panic/flee mode if several triggers coincide (people, loud dog barking and noises like motorcycles/construction). So pleased to find Doggy Dan and seeing positive changes after just two weeks. Feeding time is calm after using the gesture eating and "thank you" when he barks works a treat. I realized I'm babying my dog too much and trying to be his best pal instead of a leader so I'm working hard on that. We've changed to the no pull harness and love that. Doggy Dans video clips really help bring the philosophy together and I love his attitude. He is calm, clear, firm but so kind and loving with dogs and very down to earth and relatable. I've got great help too from the AI coach and the daily emails and videos help keep us on track and feeling positive. We've still got a mountain to climb with our pup but I finally feel hopeful and supported. We'd tried trainers, behavior specialists and all sorts before finding Doggy Dan and this is by far our best investment. Can't recommend you trying this highly enough. Photo of our boy.
Jackie Ward profile picture
Jackie Ward
13 August 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
Absolutely amazing transformation in just a few days. Just need to stick to the 5 Golden rules 🙂
Martine Adkin profile picture
Martine Adkin
13 July 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
+0
I couldn’t believe my dog’s problem resolved completely within a week! Easy but not easy if you are inconsistent with the 5 rules. I highly recommend this method! Somethings don’t seem important or relevant but they are!
Dawn McCordic profile picture
Dawn McCordic
13 July 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
+0
I just started my training about 2 weeks ago, and I do mean MY training. My 2 girls are really responding to my changes in how I am relating to them better. Thank you Doggy Dan, I really needed this win, 2 reactive dogs and we have made progress with the 5 golden rules and we have not with anything else. Crystal Gayle the Red Heeler and Sadie the Border Collie.
Betty Nicholl profile picture
Betty Nicholl
11 July 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
+3
For three years, I tried every treat-based method and expensive course to stop my large, powerful male dog from pulling on the leash, barking, and stressing out when his energy got too high on our walks. (So while he is a farm dog who enjoys total freedom off-leash on our farm most of the day, on-leash in the city, he totally lost it). He was practically hanging from the leash, two feet in the air (almost strangling himself), always demanding to walk in front and make all the decisions. Absolutely nothing worked—until I found Doggy Dan! 🏆 After just a couple of weeks implementing The 5 Golden Rules, the transformation is absolutely mind-blowing!!! By focusing on connection and calm leadership rather than rigid commands, my dog has FINALLY reconnected with his natural calmness (that has actually always been there inside him) ❤️❤️ When we walk through town now, I look down at my dog walking in a perfect "heel." The leash hangs completely loose, and that loose leash really says it all 👍👍👍 He does not pull, bark, or growl AT ALL when other dogs bark at him!😱 Yes, he looks at them and is interested, but he remains completely calm. We pass shouting people, groups of kids on scooters, and dogs barking aggressively behind gates—he is interested, but he remains entirely unfazed. Just yesterday, we stopped in front of a fence with chickens walking in a garden, and he just stood there watching curiously, staying completely still. And as we walked across a large, grassy schoolyard, we suddenly crossed paths with two rabbits—when I told him to, he immediately sat down. Of course, he was highly interested, but he sat completely, utterly still! I constantly find myself thinking: This can NOT be my dog, LOL! 🐇🐓 Dan refers to himself as a dog trainer, but in my humble opinion he is a dog philosopher. The course is incredibly generous, filled with hundreds of real-life videos from every situation imaginable, offering a massive toolkit for an amazing price. I am so excited to continue this course, so happy about the progress, and so looking forward to the future with this beloved dog of mine. I HIGHLY recommend it! ⭐⭐⭐⭐⭐
Ingrid-Tove Astrup profile picture
Ingrid-Tove Astrup
8 July 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
+0
I've only been working the program for a week and already are seeing some great improvements with an overexcitable, energetic, barking at everything, and fun Maltipoo. I'm focusing on the 5 golden rules and watching the training videos. Thanks Doggy Dan!
Rebecca Cheney profile picture
Rebecca Cheney
4 July 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
In a matter of days my 5 year old Frenchie is calmer and seems happier, albeit not happy that I'm ignoring him but it works! I live alone so he thinks he should be boss and protect me from every visitor but he didn't even bark at the window cleaner yesterday, just followed him around each window. My life might be my own soon, thank you!
Shauna profile picture
Shauna
2 July 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
+4
The Golden rules i now understand are NOT called GOLDEN RULES FOR NO REASON! WOW , JUST WOW, I WAS DOING ALL 5 WRONG !
Tim Waldner profile picture
Tim Waldner
2 July 2026
Google star 1Google star 2Google star 3Google star 4Google star 5
+0
We have adopted a Poodle and he us very high energy, anxious and insecure. I joined the online program after I watched the free online webinar about the 5 Golden Rules. While watching the webinar all 3 of my dogs ran off barking... I calmly called out "thank you" and they all came back to me.. from that moment I was hooked. I love the fact that we use minimal sound in this technique as I can become anxious and unsure in my tone. I have seen results with the new Poodle and I am exited about our future. Thanks Doggy Dan, you are a gem 👌🐾🐾🐾
Jane Uprichard profile picture
Jane Uprichard
22 June 2026
FREE webinar:

How to Solve Dog Reactivity WITHOUT Food Bribes, Tricks, or Force

dog training to stop unwanted jumping and barking

Limited Spaces!