That enthusiastic face-licking greeting when you come home is a universal dog owner experience. But what's really driving this behavior?
1. Affection and Bonding
Licking releases endorphins in dogs, creating a sense of comfort and pleasure. When your dog licks you, it strengthens the bond between you through physical contact. This is supported by research showing that social grooming (allogrooming) in many mammalian species, including canids, serves a bonding function that goes beyond hygiene. Licking also triggers oxytocin release in both the dog and the human recipient.
2. Communication and Respect
In wolf packs and wild dog groups, subordinate members lick the muzzles of dominant individuals as a sign of deference and social cohesion. Puppies lick their mother's mouth to stimulate food regurgitation — a behavior that persists in modified form in domestic dogs. When your dog licks your face or hands, they may be communicating respect, requesting attention, or expressing a desire for food or interaction.
3. You Taste Interesting
Human skin is salty, especially after exercise, and dogs' sense of taste (while much less refined than ours — they have about 1,700 taste buds compared to our 9,000) can detect salt, sweet, sour, and bitter. After meals, your hands and face carry food residue that's irresistible to your dog. Lotions, sunscreens, and other products can also attract licking behavior.
4. Seeking Information
Dogs' vomeronasal organ (Jacobson's organ) processes chemical signals that licking helps deliver. By licking you, your dog may be gathering information about where you've been, who you've been with, and what you've eaten. This is essentially their way of "reading the news" about your day. Research in Chemical Senses has shown that dogs can detect emotional states through human chemical signals (sweat, skin oils), and licking enhances this ability.
5. Anxiety or Compulsion
While occasional licking is normal, excessive or compulsive licking — of you, themselves, or surfaces — can indicate anxiety, gastrointestinal discomfort, or a compulsive disorder. A 2012 study in the Journal of Veterinary Behavior found that dogs who excessively licked surfaces (floors, walls, furniture) were significantly more likely to have GI disorders. If your dog's licking seems obsessive or has suddenly increased, a vet visit is recommended.
Is Dog Saliva Clean?
The old myth that dog saliva is cleaner than human saliva or has healing properties is false. Dog mouths contain over 600 species of bacteria, many of which are different from human oral bacteria. While infection from dog licks is rare in healthy people, immunocompromised individuals should avoid contact with dog saliva on open wounds. The CDC has documented cases of serious Capnocytophaga canimorsus infection from dog licks, though these are extremely uncommon.