Why do dogs drool when they see food? So you are about to eat a juicy steak as your dog looks at the meat on your fork with languid eyes and starts visibly drooling droplets from his mouth. If this scenario sounds all too familiar, rest assured, you're not alone Drooling at the sight of food is a perfectly normal behavior that healthy, hungry dogs tend to exhibit. Here at "Why do Dogs?" though we aren't happy about over simplistic explanations, so we went out of our way to look for an in a more depth analysis of drooling behaviors in dogs.
A Reflexive Mechanism
A human's mouth waters at the sight of tasty foods, whereas a dog may lick his chops and drool. Different ways to depict similar mechanisms. Dogs drool for the same reason our mouths water, it's the result of an overproduction of saliva. If your dog drools, don't blame him, blame instead the salivary glands which go into overdrive at the sight of food. And don't go thinking that you can simply stop drooling by teaching a dog a "no drool" command; drooling is an unconditioned, inborn reflex that dogs perform naturally and they have little or no control over it. So attempting to train a dog to stop drooling, isn't really a realistic expectation.
A Matter of Moisture
Behind the reflexive mechanism of drooling at the sight of food are several important functions. One of them is to help people and dogs swallow food. Russian physiologist 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.
Natural Born Droolers
Not all dogs drool visibly at the sight of food. If your dog belongs to a breed that has pendulous lips such as the bloodhound, Saint Bernard or English mastiff, you're more likely to see him drool, so keep a cloth handy at all times around these fellows. Dogs with normal lips are less likely to drool so profusely and some dogs would rather lick that trickle of drool before it has time to drip and become visible. If your dog is not the type who begs at the table and consumes people foods, you'll likely only see a trickle of drool when you're involved in your dog's meal preparation.
A Pavlovian Association
Interestingly, drooling doesn't only happen in the presence of food. The mere thought of food such as the sight of the can opener, food bowl or even the sound of you opening a cabinet are often enough to elicit the drool cycle in dogs. Drooling in dogs was studied in depth by Russian physiologist Ivan Pavlov while he was researching digestive processes by observing dogs and their responses to food under a variety of conditions. As he went about with his studies, he noticed an interesting phenomenon: at some point the dogs were starting to drool even before the food was actually delivered to their mouths! The dogs were drooling at the mere sight of the technician responsible for feeding them (or even the sound of his footsteps) even when no food was around!
Despite being messy and inconvenient, Pavlov called this phenomenon of anticipatory salivation "psychic secretion" and he grew so intrigued about it, he decided to study it further for the rest of his career. He determined that stimuli could become associated with others if they were repeatedly paired. To further test his theory, he rang a bell and then gave food, and at some point, after several repetitions, the dogs started drooling at the mere sound of the bell, even if food didn't follow. This paved the path to new important discoveries in the process of learning. This form of associative learning was called classical or respondent conditioning, but in honor of Pavlov's studies, it is often also referred to as Pavlovian Conditioning.
Tips to Reduce Drooling
Not too long ago, an owner with a service dog asked for some tips on her dog drooling at restaurants. While it may be close to impossible stopping a dog from drooling at the sight and smell of food, there are ways to minimize its effects. Letting a dog wear a large bandana or bib may be a good way 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 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!
When to See the Vet
As seen, drooling in the presence of food is a normal, natural behavior in dogs. It's when the drooling occurs when no food is in sight that it can sometimes be problematic. Excessive drooling in a dog that doesn't have pendulous lips, can be a sign of problems. 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.
Did you know? Humans produce an enzyme in their saliva known as amylase to help them digest starch. Digestion in humans therefore starts in the mouth. While recent studies have discovered that dogs produce amylase as well, production does not occur in the dog's saliva but in the pancreas and intestinal tissues. This lack of salivary amylase is therefore there to remind us that nature intended not to make carbs their primary source of nutrition, points out veterinarian Jean Hofve, in an article for the Integrative Veterinary Care Journal. This lack of digestive enzymes in dog's saliva may ultimately explain why starches tend to stick to a dog's teeth triggering the insidious buildup of plaque and tartar known for causing gingivitis, claims Cindy Lizotte, a veterinarian working for Elmwood Veterinary Hospital in Moncton, Canada.