That dogs have a dazzling sense of smell is a known fact that most people are aware of, but many folks might not know much about a dog’s nostrils, those openings that allow dogs to breath in air, exhale and evaluate all those interesting smells lingering around. Like us, dogs have two nostrils, but a dog’s nostrils are quite interesting to discover more about considering their roles in taking in all sorts of smells. So today, let’s learn more about a dog’s nostrils. So here are five fascinating facts about dog nostrils just waiting to be discovered!
1) Wiggle that Nostril
Dogs have the ability to move their nostrils independently. Yes, that means one at a time. When they do this, they are evaluating the smell and perhaps even trying to determine exactly from what direction the scent is coming from. Cool, eh?
2) Pant or Sniff?
While dogs can move a nostril independently from the other, on the other hand, they are not able to pant and sniff at the same time. This is why when you present a panting dog your open hand with a bit of food on it, he will stop panting. When he does this, he’s temporarily turning off his normal breathing process and “switching on” his scent processing ability so to check it out, explains Stanley Coren in the book “How Dogs Think.”
This also explains why working scent dogs become less reliable when the weather is particularly hot. According to research conducted by Irit Gazit and Joseph Terkel, reduced olfactory efficiency was noticed in sniffer dogs when they were overheated. This can obviously turn quite problematic for search and rescue teams, but it can remedied by keeping the dogs cool and allowing them time to acclimate to hot weather.
“Dogs cannot simultaneously pant and sniff or breathe through their nose, and they have alar folds/flap on the sides of their nose that move up and out when they take a deep breath. This means you can use the movement of these folds -the dilation of the nostrils- to indicate and confirm when the dog is holding his breathe.”~Karen Overall
3) Right Nostril Bias
In humans and dogs, it’s a known fact that the brain is divided right down the middle leading to a specific hand preference. We therefore have “lefties and righties,” but what about dogs? We know that dogs seem to have a paw preference too, but even more interestingly, it looks like when it comes to dogs, nostril preference is also present and it’s used accordingly based on what they’re sniffing.
In a recent study conducted by Siniscalchi, M., et al, dogs were exposed to six different types of smell and their reactions to these smells were evaluated. The dogs were introduced to the smell of food, the smell of a female dog in heat, the scent of lemon, an odorless cotton swab, the smell of sweat coming from a vet and the smell of adrenaline.
The dogs were allowed to investigate these smells several times and watched carefully. It was noticed that when they investigated these smells for the first times, they used their right nostril. After some time though, they then switched to using their left one. The only exception to this rule occurred with the smell of the vet’s sweat and the smell of adrenaline which they must have categorized as “aversive.”
At a closer evaluation, this”right nostril bias” isn’t surprising because the olfactory system is displayed ipsilaterally (affecting the same side of the body) and therefore the right nostril is known to connect with the right side of the brain and vice versa. From previous research it’s known that the right hemisphere of the brain is the side that tends to deal with novelty and the elicitation of emotions associated with the fight or flight response, while the left hemisphere tends to deal with routine investigation, approach behavior, and attractiveness.
4) Those Interesting Slits
Why do dogs have slits on the sides of their nostrils? Well, believe it or not, even those slits have an important role. While the front part of the nostrils take in air, those slits on the sides are there so to allow the air to escape when the dog exhales. When the air flows out of the side slits, it creates a swirl that helps with the sampling of new odors. But wait there’s more! Those slits may also carry another important role, but this time, it has to do with awww, cute baby puppies…
“Here’s why this is particularly special: the photography also reveals that the slight wind generated by the exhale in fact helps pull more of the new scent in by creating a current of air over it.”~Alexandra Horowitz
5) Heat Sensors
Mother Nature may spare puppies from being able to see or hear at birth, but she was certainly generous in the olfactory department. Not only can puppies smell at birth and even prior to being born, but their noses appear to be equipped with special heat sensors.
Ever wondered how a newborn puppy is able to crawl back to mom? Momma’s smell may play a role, but Yngve Zotterman, of the Swedish Research Council, actually discovered another fascinating perk.
Basically, puppies are equipped with special heat sensors which are located around those nostril slits and the opening to their nasal passages. It has been found that these sensors are capable of detecting infrared energy that’s radiated from warm objects. Fascinating stuff!
“Evolution has provided an additional source of sensory information to help the puppy at this critical time in the form of special heat sensors in his nose”~Stanley Coren
- Siniscalchi M., Anna M. Pepe, Salvatore Dimatteo, Giorgio Vallortigara & Angelo Quaranta (2011). Sniffing with the right nostril: lateralization of response to odour stimuli by dogs, Animal Behaviour, 82 (2) 399-404. DOI:
- Irit Gazit, Joseph Terkel, Explosives detection by sniffer dogs following strenuous physical activity Applied Animal Behaviour Science, Volume 81, Issue 2, Pages 149–161
- How Dogs Think, Understanding the Canine Mind By Stanley Coren, Free Press; 1st edition (August 3, 2004)
- Why Does My Dog Act That Way?: A Complete Guide to Your Dog’s Personality, By Stanley Coren Free Press; 1 Reprint edition (December 4, 2007)
- ‘Inside of a Dog: What Dogs See, Smell, and Know, By Alexandra Horowitz, Scribner; a edition (September 28, 2010).
- Manual of Clinical Behavioral Medicine for Dogs and Cats, By Karen Overall, Mosby; 1 Pap/DVD edition (July 9, 2013)
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