Dog saliva isn’t a glamourous topic, but there are many interesting doggy saliva facts waiting to be discovered!
You likely don’t think twice about your dog’s saliva until some doggy drool lands on your furniture or, even worse, on you. Perhaps you have also observed some droplets slowly pooling into a small saliva puddle as your dog longingly stares at your juicy steak.
In a perfect world, your dog’s saliva is supposed to stay neatly tucked inside your dog’s mouth, but when it’s excessive it struggles to stay put. Additionally, in some dog breeds blessed with heavy, floppy jowls, the task is easier said than done.
If you own one of these breeds, you are likely familiar with the constant “downpour,” and are always prepared with towels to catch the inevitable "slobber slingers." But while doggy drool might seem like a mundane topic, there’s actually a lot more to it.
While it's well-known that doggy kisses with its associated slobber is a sign of affection, there are lesser-known risks of canine saliva that are important to be aware of. From bacteria in dog saliva to severe allergies to dog saliva, and even rare cases leading to amputation or death, it’s essential to stay informed.
So buckle up, because we’re diving into the wild world of dog saliva—and yes, discovering these facts is way more fascinating than you’d think!
Pavlov Studied Dog Saliva
Let’s start discovering more about a dog’s saliva by taking a trip back in the past. There was this guy going by the name of Ivan Pavlov who ditched his plans for the priesthood for exploring the digestive system of mammals.
This Russian physiologist, being the curious mind he was, hooked up a tube to a dog’s salivary glands so as to keep track of how much saliva a dog produced when presented with food.
No surprise there-dogs drooled the moment they got a mere whiff of food. This proved to him that the biological production of saliva had an important function in the digestive process. No surprise there.
But then, Pavlov stumbled upon an intriguing phenomenon: even when there was no food in sight, the dogs were still drooling!
At first, this just seemed like an annoying side effect as the tubes kept filling up with saliva, but after careful observation Pavlov soon noticed that the dogs were starting to drool upon spotting the scientists walking around with their white lab coats! Lightbulb moment!
What really was happening is that dogs have been “trained” (the better word is conditioned) to drool on cue.
To prove his hypothesis, Pavlov next started experimenting with sounds, like he started ringing a metronome and then presenting food and voila-the dogs started drooling from just hearing it, even when there was no food around.
Dog Saliva Can Help Clean Wounds
Let’s now fast forward to the world of canine first aid. Before humans came along with bandages and antiseptic wipes, dogs relied on their own, natural built-in medical kit: their tongues.
A good old lick would clean up any dirt or debris present on the wound's surface and their saliva. See? Dog saliva isn’t there just for slobbering on your furniture.
Dog saliva has been often reported for having some type of miracle healing properties. Perhaps there is some truth to this. After all, have you ever noticed how quickly wounds in your mouth tend to heal?
To attain the answer to this we had to go dig up some studies. According to a study conducted by Benjamin L. Hart, and Karen L. Powell, saliva in male and female dogs was found to have antibacterial properties, in particular against Escherichia coli and Streptococcus canis.
Too Much Licking Isn’t Good
Before you let your dog go full-on nurse, be warned: too much licking can be a bad thing. Indeed, excessive licking can irritate wounds, and keeping an area moist with saliva for too long opens up the door to nasty bacteria.
That’s why the infamous "cone of shame" AKA the infamous Elizabethan Collar comes in handy. This is important to prevent making a small cut turn into a scary infection.
Furthermore, when dog licking gets out of hand, such obsessive licking can lead to something called a lick granuloma, basically a sore that is quite challenging to heal and that is caused by, you guessed it, too much licking.
Dog Saliva Helps Dogs Digest
On the less dramatic side, your dog’s saliva plays a crucial role in doggy digestion. We touched on this briefly when talking about Pavlov, but here’s some more in depth info about it.
As your gulps down food, saliva helps moisten and lubricate food, turning it into a slimy blob (it’s officially called a “bolus” for those nerds out there) that easily slides down the esophagus like a water slide.
Ivan Pavlov noticed how when he fed dogs dry, hard foods, the dogs produced a heavy flow of saliva; whereas, when the dogs were fed watery foods, the dogs produced considerably less, points out Paul Chance in his book "Learning and Behavior: Active Learning Edition. "
The saliva therefore plays an important role in helping moisten food so it's easier to swallow before reaching the stomach.
Now here’s some bonus trivia: according to Dukes' Physiology of Domestic Animals different types of salivary glands produce different types of saliva. Some salivary glands make watery, amylase-containing saliva that helps digest starches, while others produce thicker, mucus-like saliva to keep that food moving smoothly.
Presence of Amylase
You might have heard the saying "the digestive process starts in the mouth.” While in humans, saliva helps initiate the digestion of starch courtesy of the presence of amylase, studies have found that, in dogs, this was either lacking or it was found at low levels.
This is likely because dogs are not considered as omnivorous as humans. However, the amount of amylase found in dog saliva may vary based on diet.
For instance, according to a 2018 study, dogs in Thailand which are often fed a diet rich in rice and starch may have amylase in their saliva.
Similarly, people known for consuming high carbohydrate diets—such as the Japanese and European Americans tend to digest starches better than people with starch-poor diets, such as the Mbuti in Africa.
There is suspicion that dogs developed an ability to digest starch during domestication. This allowed dogs to tolerate a diet that was relatively rich in starch (Axelsson et al. 2013).
When compared to wolves, dogs were found to have 4 to 30 copies of the gene for amylase, whereas, wolves had only two copies. This gene this is 28-fold more active in dogs, tells us that the ability to digest starches must have been part of the domestication process.
The early dogs that evolved more efficient starch digestion had an advantage, explains evolutionary geneticist Erik Axelsson from Uppsala University in Sweden in an article for Science.
From our results, dog saliva had lower amounts of alpha-amylase than human saliva which is possibly due to the natural selection associated with digestion capability and food appreciation. (Phutsa Sanguansermsri et al. 2018)
Dog Saliva is Produced By Various Glands
If your dog produces saliva, you must thank his salivary glands which are found in your dog's upper and lower jaw. Want to know more about them? Here’s a little rundown:
Zygomatic glands
These salivary glands are found by your dog’s cheek bone near the dog's eyes
Parotid glands
These salivary glands are found where the head meets the neck
Sublingual glands
These salivary glands are found under your dog's tongue
Mandibular glands
These salivary glands are found by your dog’s lower jaw (the mandible)
Caution With Excessive Saliva
Excess salivation, gulping and repeated lip swallowing should send you on a "barf alert." Make sure to have your dog move over to a tiled area for an easy clean up and keep plenty of kitchen towels ready: your dog is likely to lose his lunch at any moment.
Why in the world do dogs drool though when they are getting sick? This may sound like quite a controversy, especially if we think that dogs (and humans) drool in anticipation of food and saliva helps kick start the digestive process!
Well, here's a fascinating fact: on top of saliva pooling in the mouth as if hosting a pool party when in the presence of food, saliva also assumes a noble protective role.
Since vomit is very acidic in nature, the increase in saliva seen when one becomes nauseous is meant to help minimize erosion to the mouth and tooth enamel caused by those potent gastric acids.
Did you know? Your dog's salivary glands also increase salivation and may trigger foaming at the mouth when there are irritating substances in the mouth such as when dogs lick off some shampoo or happen to lick a toad.
Saliva Can Help Dogs Cool Down
Your dog doesn’t pant to just show off his long tongue. When your dog’s hot, panting is his primary method to help him cool down and your dog's saliva can play a role in helping him out when temperatures soar or after exercising.
Here's a little insight into the process. When your dog is hot, he will keep his mouth open and breathe quickly. This heavy panting allows the saliva-moistened surfaces of his mouth and tongue to cool down by increasing evaporation.
As the saliva on your dog’s tongue evaporates, blood vessels that run close to the surface cool down. This cool blood then circulates throughout your dog’s body, lowering his core temperature. It’s nature’s air conditioning—in doggy drool style.
This evaporation is ultimately one of the several ways dogs cool down when they're hot.
Dog Saliva Can Stain
If you own a white dog with a licking habit, you’ll be quick to notice some reddish-brown stains around their mouth and possibly by the paws. In this case, you can blame a dog’s saliva.
According to Muller and Kirk's Small Animal Dermatology the main cause for dog saliva and dog tears to cause unsightly reddish stains is due to the presence of porphyrins, special iron-containing molecules that result from the natural breakdown of red blood cells.
While most porphyrins are excreted through urine, some get sneaky and find their way out through tears and saliva, causing those unsightly stains.
Some Dogs Are Naturally Born Droolers
As mentioned earlier, for some dog breeds, drooling is just part of the package. If you’ve ever met a Saint Bernard, you know what I’m talking about—drool slingers that can coat walls, windows, ceilings, and floors in record time. It's very difficult to come by a Saint Bernard with a dry mouth.
In this case, you’ll need to blame the shape of a dog's upper lip (the so-called flews) which can surely play a role in how predisposed a dog may be to drooling.
Many seasoned dog owners though have simply learned to cope with the drooling issue. "You just always carry a towel and learn to live with it," explains a fancier to the American Kennel Club Gazette.
Did You Know? A 44-pound dog fed kibble can produce anywhere between a half a liter up to 1 liter of saliva a day! Woah, that’s a whole lot of spit!
Dog Saliva Has a Different pH
When dog saliva is compared to human saliva, doggy saliva presents with a higher pH. Dogs typically have a pH around 8.5, whereas human saliva ranges around 6.5 to 7.5.
This difference may play a role in a dog’s reputation for not needing cavities filled as often as it happens in humans. However, there is a tradeoff. A higher pH leads to less cavities, but a higher predisposition for gingivitis (gum disease) due to higher calculus formation.
Dog Saliva is Not Clean as Thought
Is dog saliva clean? Now that’s a good question! For starters, a dog’s mouth is known to harbor a smorgasbord of bacteria. Research has found that a dog’s mouth is teeming with about 600 types of bacteria. How crazy is that?
While dog saliva contains a wide range of bacteria, some of which can be beneficial in wound healing, there are some others that can do more harm than good and some may even be quite dangerous if they make their way inside human skin.
For instance, consider that dog saliva may contain strains of Capnocytophaga, which can cause severe infections in some folks, especially those with weakened immune systems.
While a dog bite is a way people may get infected, it can also happen if a dog’s saliva ends up on an open wound or sore. In people with a weakened immune system, this bacteria may cause serious infections that may progress to gangrene and sepsis.
Sadly, there are even stories of dog saliva amputees as seen in some documented cases.
Did you know? Diseases that are passed from animals to humans are known as zoonotic diseases.
Risks for Rabies
The rabies virus is secreted in saliva and therefore, the most common transmission form is through bite wounds. Namely, when a rabies infected animal bites a dog it breaks its skin and the virus enters the dog’s bloodstream.
While the easiest and simplest transmission is when an infected animal bites another animal or human, this is not the only mode of transmission.
The virus can also be transmitted if an open wound is exposed to the saliva of an infected animal. For example, if a rabid dog licks the wound of another dog it can transmit the virus.
Most cases of rabies are transmitted to dogs from exposure to wildlife reservoir animals like foxes, raccoons, and bats.
Luckily, rabies is a 100 percent preventable disease. The cornerstone of prevention is vaccination. Dogs need to be regularly vaccinated against rabies starting from when they are three to four months old and then every year or every three years, depending on the state’s regulations, explains veterinarian Dr. Ivana Crnec.
Allergies to Dog Saliva Are For Real
When people say they are allergic to dogs, you’ll likely imagine these poor folks reacting to their dander and fur, but allergies to dog saliva are more common than you may think.
Proteins found in dog saliva are the main culprits which are known for triggering allergic reactions in susceptible individuals. The reactions may range from minor sneezing and teary eyes to severe respiratory issues.
-- Additional Info About Dog Saliva --
Following is some additional info and frequently asked questions about dog saliva that you may have been wondering about.
Why Is My Dog Salivating So Much When There is No Food Around?
If there is no good reason for drooling, consider that your dog may be suffering from some medical problem.
Medical causes of drooling in dogs may include gum disease, teeth problems, nausea, a foreign body stuck in the mouth or exposure to toxins. Some dogs may also drool when excited, anxious or in pain.
Can You Train a Dog Not to Drool?
Among the interesting questions dog owners asked me when working for an animal hospital was whether a service dog can be trained to stop drooling at restaurants.
While it may be close to impossible to stop a dog from drooling at the sight and smell of food, as drooling is an inborn reflex that dogs perform naturally and they have little or no control over it, there are some ways to minimize its effects.
For instance, you can let a dog wear a large bandana or a bib to catch that drool and prevent it from forming a puddle at least while the dog is lying down.
Another option is training the dog to lie down on a mat so as to minimize messes on floors. The mat can then be placed in a bag and then tossed in the washing machine once home. Of course, bringing plenty of towels helps too!
Is Dog Saliva Antiseptic?
While in the Middle Ages, people were often encouraging dogs to lick their wounds, in the belief of dog saliva accelerating healing, nowadays we know that dog saliva isn't as good as thought.
Studies have found that dog saliva contains special proteins which play important roles in helping reduce inflammation and killing or inhibiting the growth of certain bacteria.
According to a study dog saliva was found to have antibacterial properties, in particular against Escherichia coli and Streptococcus canis. This comes handy when mother dogs are licking their newborn pups which are predisposed to highly fatal coliform enteritis and septicemia.
However, according to a Science Fair Project, when dog saliva was compared to Neosporin, Neosporin was proven to have superior antimicrobial activities.
While dog saliva appears to help slow the growth of bacteria for a little while, it also adds bacteria. You may therefore want to think twice about letting your dog lick your wounds.
According to a study, canine saliva is rich in potentially risky bacteria including Porphyromonas, Capnocytophaga, Corynebacterium, Fusobacterium, Pasteurella, Porphyromonas, Staphylococcus and Streptococcus species.
These are some of the most relevant bacteria causing dangerous dog bite infections.
References:
Public Broadcasting Service (PBS), People and Discoveries, Ivan Pavlov
Antibacterial properties of saliva: Role in maternal periparturient grooming and in licking wounds Benjamin L. Hart, Karen L. Powell, Physiology & Behavior Volume 48, Issue 3, September 1990, Pages 383–386
Torres SMF, Furrow E, Souza CP, GranickJL, de Jong EP, Griffin TJ, et al. (2018) Salivaryproteomics of healthy dogs: An in depth catalog. PLoS ONE
Lussi A, Jaeggi T. Erosion - diagnosis and risk factors. Clin Oral Investig. 2008;12:S5–13.
Pasha, Sabah & Inui, Taichi & Chapple, Iain & Harris, Stephen & Holcombe, Lucy & Grant, Melissa. (2018). The Saliva Proteome of Dogs: Variations Within and Between Breeds and Between Species
Edgar, W. M., Saliva and dental health. Clinical implications of saliva: report of a consensus meeting. British dental journal 1990
Al-Amrah, Hadba & Aburokba, Reham & Alotiby, Asseel & AlJuhani, Badriyah & Huri, Hadeel & garni, Noha & Aljedani, Reem. (2024). The Impact of Dogs Oral Microbiota on Human Health
Centers for Disease Control: About Capnocytophaga
Polovic N, Waden K, Binnmyr J, et al. Dog saliva ‐ an important source of dog allergens. Allergy. 2013;68(5):585‐592