Dogs lick people for any number of reasons:
- They lick to demonstrate affection or because we've taken the trouble to flavor ourselves with sweat or lotion
- Licking prompts a reaction from the unwilling human recipient, further fueling attention-seeking behavior
- Occasionally, dogs lick out of habit or compulsion
Licking is usually harmless and can be safely ignored.
Affection and instinct
Dog owners who enjoy receiving affection this way describe their pet’s licking as “doggy kisses,” and they’re not far off from the truth. Dogs most likely lick human faces as an offshoot of natural canine social behavior–they lick each other as a greeting, a show of submission, or even an indicator of familiarity.
Younger dogs are more likely to lick their human’s faces in an effort to solicit care or attention. This behavior is thought to be learned from their mothers, who lick their puppies to groom them. As these puppies age, they mimic the licking and pass it onto humans.
While dogs are not wolves, infant canines in general have been observed licking their parents’ mouths to stimulate regurgitation. The partially digested food is Nature’s baby food. It may be natural, but puppies thrive on age-appropriate commercial diets, so please don’t feel the need to parent your pup in this fashion.
Attention-seeking behavior
Dogs start licking for any reason, but just like any other behavior, they continue to lick because it’s getting them the results they want. Common reactions to a sloppy lick include: laughing, smiling, petting, funny noises, pushing away, scolding, etc.
What do these all have in common? Whether it’s positive or negative, attention reinforces behavior.
If you suspect your dog is licking you to get attention, ignore them or remove yourself when they start applying their tongue to your skin. When they’re behaving in a more appropriate way, such as sitting, give them the attention they’re craving!
Flavor
Dogs have a much stronger sense of smell than humans and can detect residue on our skin that we might not. We might consider ourselves odorless or neutral, but to our dog’s nose, we walk around flavored with sweat, lotion, dirt, food, or other substances. If your dog seems most inclined to lick you after a walk or bath, they may simply be tasting you.
We often remind people that dogs experience the world through their mouths–which means mouthing and licking! Most people prefer the latter over the former, and licking is a less painful outlet for a puppy’s natural urge to put everything in their mouth. Many adult dogs grow out of this habit if owners take care to avoid reinforcing it.
Dogs are sometimes drawn to lick open wounds on us. Unfortunately, while human and animal studies have indicated some wound healing properties in their saliva, their mouths are not sterile and contain hundreds of different bacteria, fungi, and viruses. Although uncommon, certain bacterial and parasite infections are zoonotic and can be dangerous, especially in immunocompromised people.
Compulsive behaviors
While most motivations for licking are harmless, compulsive licking can be cause for concern. Compulsive licking should be repetitive, constant, and serve no obvious purpose. It may be difficult to interrupt or, when interrupted, immediately resumed.
Repetitive behaviors are most likely to develop during adolescence. The sudden onset of compulsive behaviors in middle-aged or geriatric dogs is more likely to have a medical cause than neurological or psychological.
Canine acral lick dermatitis, colloquially referred to as canine obsessive compulsive disorder, entered veterinary journals in 1991. Treatment consists of a combination of antihistamines, corticosteroids, bandages, and Elizabethan collars. Because infection is almost always present, antibiotics are also prescribed.
