Layne is an animal lover who grew up in a household full of rescued critters. She is a registered veterinary technician.
Why Do Dogs Smell so Much?
When we say dogs smell, we are referring to sniffing around and taking interest in scent. Yes, dogs smell in general,(that’s why we bathe them regularly), but when it comes to them smelling—each other, stinky things, you, your mouth, their collars, and each other's bums—there’s a lot of method to the madness. Smelling is a major part of communication in the dog world. It’s how they learn about their environment, other dogs, and the world around them, and it's how they say "hello" to one another.
A dog's sense of smell is 10,000 to 100,000 times greater than humans, depending on the breed (German Shepherds and Labradors rank highest in smell-ability as do scent hounds; brachycephalic breeds are not as skilled). Scent hounds, too, like Basset Hounds, benefit from having skin folds on their face. These folds help to trap scent particles and channel them to the proper olfactory regions for heightened scent detection. This is why dogs are used for tasks such as detecting drugs, explosives, cadavers, drops in blood pressure for diabetics, and more. According to Dr Nappier as quoted on PETMD, “[A dog’s nose] is so sensitive that [dogs can] detect the equivalent of a 1/2 a teaspoon of sugar in an Olympic-sized swimming pool.”
What Can Dogs Detect With Their Nose?
Dogs have evolved to use their scent for survival. They can use it to determine if another dog is suitable for mating, a relative, if food is edible, toxic, or poisonous, and when a predator or prey is near. Dogs can also tell how long you’ve been gone from the house based on how your smell dissipates or fades over time. That’s why they seem to know when someone is due home at a particular hour. A dog’s olfactory receptors and ability to smell are their primary means of communication. This is why, according to AnimalPlanet.com, the portion of the dog’s brain that controls smell is 40 times larger than ours.
Why Do Dogs Smell Each Other?
Dogs smell each other because it’s the equivalent of two humans giving a handshake and a quick introduction. Dogs possess apocrine glands around the body. Apocrine glands are sweat glands that give off pheromones and communicate a dog’s status—reproductive status, age, sex, interactions, travel history, and even disposition. Dogs get a lot of information from smelling each other. Dogs can also sense when others dogs are sick just from the scents that are emitted.
Why Do Dogs Sniff Each Other's Rear Ends?
When two dogs greet each other, they are simply gathering information about one another. Dogs sniff each other’s bums or butts because there are a number of apocrine glands near the genitals and rear, so it’s only natural that dogs reach for this area to pick up on pheromones that communicate everything they need to know about the other dog that they are greeting. The anal sacs of the dog, for example, are especially potent (stinky) and carry a lot of scented insight for the greeting dog to interpret. The scent of the anal sac glands can also divulge information about a dog’s overall health and diet.
Dogs have what’s called the Jacobson’s organ in their olfactory chambers. It contains two fluid-filled sacs that allow dogs to smell and taste things simultaneously. They can sift through smells like poop, pee, and urine to separately detect things like a female dog’s reproductive status. It is this part of the nose that allows them to ignore anything that is poop-scented so that they can pick up on the more interesting chemicals that are thrown into the mix—fascinating!
Why Does My Dog Sniff My Crotch?
Dogs will sniff people's crotches and it can be rather embarrassing, but they don't know that what they're doing is inappropriate if they've never been corrected. If you’ve just exercised and haven’t showered, if you’ve been intimate with someone, if you are menstruating, or you have recently given birth, it's likely that a dog will try to sniff you if given the opportunity. Dogs don’t realize that they are being rude, and unfortunately, it’s especially embarrassing if you are out in public or over at someone’s house and the dog is more interesting in sniffing your private parts than anything else that's around them.
How to Stop a Dog From Smelling Your Crotch
You can discourage a dog from smelling your crotch by diverting their attention. It’s also the owner’s responsibility to watch their dog when they introduce them to other people. If their dog is harassing a visitor by sniffing their private parts, it’s also their responsibility to break the behavior as not to embarrass the guest. Regardless, there is a way to interrupt the undesirable behavior:
- Stop whatever you’re doing and focus on the dog. You might even put your back against something or hold your bag in front of you to block them.
- Get the dog’s attention and call them by name. It helps to say something like “Jake, look here.”
- Get the dog’s favorite toy or treat and hold it at the height of your crotch and draw the dog’s nose away at eye level until they follow the treat or ball completely and away from your body.
- If you can, get them to sit and wait for a reward. Hold their attention here.
- Once you’ve made eye contact with them and they are focused, give them the treat or toy award and deliver tons of verbal praise. You can say “Good, Jake” or “Yes, Jake.”
- Do this over and over again until it is a learned behavior. Practice makes perfect.
Sniffing My Mouth
For the same reason that your dog will sniff your crotch, your dog will sniff your mouth. It is ok to let your dog sniff your mouth just to feed their curiosity, but you should always be careful with dogs you are not familiar with. Many dogs do not like having your face in their face and they especially do not like having air blown into their face; it can even make them snap or bite if you’re not careful. Dogs can pick up on a lot from simply smelling your breath, as we'll dig into below.
Sniffing Out Medical Conditions in Humans
Dogs smell your mouth because your mouth communicates a lot about you. This is why some working breeds are actually trained to sniff out (or generally detect) biological changes in the body which indicate things like cancers or lung cancer, migraines, narcolepsy, seizures, fear and stress (panic attacks) bladder and urinary issues, and low blood sugar and blood sugar fluctuations in diabetic peoples.
Sniffing Their Collars and Leash
Dogs like to sniff their collars and leash because it smells like them. Their leash and collar belong to them, and detecting their odor on it is reassuring. Smelling their belongings is a bit like you walking into your home after traveling for a while and suddenly being reminded of the scent of your house. It's also like pulling your laundry out of the wash after using the same detergent over and over again and smelling something familiar. If you have a partner, it's a lot like smelling their scent on their clothing and enjoying it. Familiar scents that have positive associations make your dog happy.
Do Dogs Like Their Owner’s Scent?
Yes, dogs find their owner’s scent comforting and will actively seek it out when in a location with plenty of other smells. According to NationalGeographic.com, dogs experience a sense of pleasure (or something like it) when they smell their owner. (People and dogs have bonded for over 40,000 years, after all.) This research was conducted by Dr. Gregory Berns, neuroeconomist, at Emory University. Berns conducted fMRI scans on dogs which revealed real-time changes in their brain activity when presented with a stimulus.
The dogs were presented with swabs (the scent) of familiar people (the main handler in the household). From the fMRI results, it appears the dogs experienced something close to comfort and pleasure upon smelling the scent of their caretaker. What this means is that if your dog suffers from separation anxiety, leaving them with an article of clothing or something to sleep on that smells like you will surely help them to feel less alone and less anxious. Therefore, dogs do have a positive association with the scent of their guardian.
Do Dogs Get Jealous When They Smell Other Dogs on You?
Dogs don’t necessarily get jealous when they smell another dog on you, but they do wonder where you've been, who you've been with, and they do have a sense of “fairness.” They might be more curious than anything, like where were you, who is this, and where are they from? Dogs, in general, are social and like to meet other dogs, so it’s likely that when they smell another pet on you they just want to know more about them and when they can meet them, too.
Keep in mind that some dogs that have behavioral issues or are undersocialized might get distressed when smelling another dog or another animal on you. It’s not comfortable for them to pick up on another animal without knowing the back story. They might be wondering if this dog or animal will show up in their territory or if you were in a safe situation, or not.
Why Do Dogs Like to Roll in Smelly Stuff?
Dogs roll in smelly stuff like dead things and poo for a number of reasons, but the most straightforward reason is instinct. Dogs roll in smelly things to mask their scent so that they can either hide from predators or sneak up on prey. Wolves, to this day, roll in caracasses and the droppings of herbivores so they can smell more similar to the very prey that are after. It’s simply an evolutionary carryover from their wild ancestors.
Any time you catch your dog sniffing the grass and rolling in it, it’s likely that they detected something stinky there. While it’s cute and it looks like your dog is simply innocently enjoying their time in an open, green field, they are probably into more nefarious things.
How to Stop Your Dog From Rolling in Stinky Stuff
To stop your dog from rolling in stinky stuff, do the following:
- First, scan your yard for anything gross. Pick up any poop from your dog or others before you let them out. Pick up any rotting fruit that may have fallen or any compost that may be sitting in the soil of your yard.
- Consider hosing down your lawn first before letting your dog run around in order to dilute any scents or droppings from other animals that might have crossed your lawn in the evening. If you live in a place where there are deer or horses or horse manure, make sure to avoid letting your dog off leash in these areas. Even a long lead can help.
- Train your dog to have good recall with clicker training or by working with a behaviorist.
- Watch your dog’s body language carefully; you can usually tell when your dog starts to sniff to poop or when they start to sniff to flop down and roll on something stinky. Catch the behavior so you can interrupt it.
- Interrupt the rolling behavior with a distraction, like throwing their favorite toy, a ball, or even a offering them their favorite treat upon calling their name.
- Be sure to praise your dog lavishly for responding correctly.
Unfortunately, dogs just like stinky stuff, and you can never really extinguish that behavior in them entirely. It really comes down to instinct. You can, however, prevent them from bringing nasty smells into the house and stop them from inappropriate sniffing that might embarrass others with some fairly easy techniques, as mentioned above.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2021 Laynie H
Laynie H (author) from Bend, Oregon on January 24, 2021:
Hi Liz, labradors are notorious for loving stinky things and rolling in them! Their fur also picks up the scent easily.
Laynie H (author) from Bend, Oregon on January 24, 2021:
Hi Peggy, thanks for reading. Dogs amaze me. That is a funny story about Jiggs. I once was caretaking an adult hound and she started sniffing the ground furiously right before an earthquake hit (a long one at that!). It was amazing to see her hypersensitivity in action. Hope you are doing well.
Peggy Woods from Houston, Texas on January 19, 2021:
Dogs have amazing olfactory senses that explain much of this behavior. I remember my mother telling me how often they had to bathe Jiggs, their dog, who would love to roll in dead fish that had washed up on the shoreline of their summer cottage. It is good that some dogs are used to sniff diseases, drugs, etc. This is an excellent article.
Liz Westwood from UK on January 18, 2021:
This article explains a lot. The labrador I sometimes walk smells a lot. Now I know why. He also rolled in mess left by a fox. That took a lot of cleaning after to get rid of the foul smell.