Dogs Lick Each Other? Canine Social Grooming
Discover why dogs lick each other, from evolutionary wolf behavior to modern social bonding. Science-backed answers plus when licking signals a problem.
Quick Answer: Dogs lick each other primarily as a social bonding behavior rooted in ancestral wolf pack dynamics. Mutual licking (allogrooming) releases endorphins and oxytocin in both dogs, reinforcing social bonds, reducing tension, and communicating submission or affection. Puppies lick their mother's face to solicit regurgitated food — an evolutionary holdover from wolves — and adult dogs continue face-licking as a greeting and appeasement signal. While most inter-dog licking is perfectly normal, obsessive licking focused on one body part can signal pain, infection, or anxiety in the recipient dog.
The Neurochemistry of Canine Licking: What Happens in the Brain
When your dog licks another dog, a cascade of neurochemical events unfolds that science has only recently begun to map. Understanding the physiological mechanism behind licking reveals why this behavior is so deeply ingrained — and so difficult to extinguish even when owners try.
The Endorphin-Oxytocin Feedback Loop
Research published in the journal Applied Animal Behaviour Science demonstrates that affiliative behaviors like allogrooming trigger the release of two key neurochemicals:
- Beta-endorphins: These endogenous opioids produce a mild euphoric sensation, making licking intrinsically rewarding for the dog performing the behavior. This is why licking is self-reinforcing — the dog literally feels good doing it.
- Oxytocin: Often called the "bonding hormone," oxytocin surges in both the licker and the recipient during mutual grooming. A 2015 study by Nagasawa et al. at Azabu University showed that oxytocin levels rose significantly in dogs during positive social interactions, and subsequent research extended these findings to dog-dog interactions.
The combination creates a positive feedback loop: licking feels good → dog licks more → bond strengthens → more oxytocin released → more licking motivation.
The Role of the Vomeronasal Organ
Dogs don't just lick to bond — they lick to gather information. The canine vomeronasal organ (also called Jacobson's organ), located on the roof of the mouth between the nasal cavity and oral cavity, detects pheromones and chemical signals that the primary olfactory system cannot process.
When a dog licks another dog's face, ears, or genital region, they are sampling:
- Reproductive status: Hormonal markers indicating estrus cycle phase or neuter status
- Stress levels: Cortisol metabolites present in saliva and skin secretions
- Health indicators: Changes in skin chemistry that may signal illness or infection
- Individual identity: Unique chemical signatures that help dogs recognize specific individuals
This is how dogs "read" each other. A thorough face-licking session is essentially a chemical status update — far more informative than visual cues alone.
Evolutionary Origins: From Wolf Pups to Modern Dogs
The Wolf Connection
In wild wolf packs (Canis lupus), face-licking originates as a food-solicitation behavior. Wolf pups between 3-8 weeks old lick the muzzle of returning adult pack members, triggering a regurgitation reflex. The adult wolf then vomits partially digested food for the pups to eat — a critical survival mechanism before pups can hunt independently.
This behavior is documented extensively in wolf ethology research, including David Mech's long-term field studies on Isle Royale. Even though domestic dogs (Canis lupus familiaris) have been separated from wolves for approximately 15,000–40,000 years, this muzzle-licking behavior persists as a neotenized trait — meaning dogs retain juvenile wolf behaviors into adulthood.
From Food Solicitation to Social Greeting
In domestic dogs, the regurgitation trigger has largely been lost (most dogs do not regurgitate food in response to face-licking), but the behavioral pattern remains. Over thousands of generations of domestication, muzzle-licking shifted function from food solicitation to:
- Appeasement signaling: A lower-ranking dog licks the face of a higher-ranking dog to communicate non-threatening intent and deference
- Greeting ritual: Dogs meeting after separation engage in face-licking as a reunion behavior, similar to wolf pack members returning from a hunt
- Conflict de-escalation: During tense encounters, one dog may offer face-licking as a calming signal to prevent aggression
This evolutionary repurposing — where a juvenile food-begging behavior becomes an adult social tool — is a textbook example of behavioral neoteny, one of the defining features of canine domestication.
What Does It Mean When My Dog Licks Another Dog?
Context determines meaning. The same licking behavior can signal completely different things depending on body language, duration, location on the body, and the relationship between the two dogs.
| Licking Location | Accompanying Body Language | Likely Meaning |
|---|---|---|
| Face/muzzle (brief) | Relaxed posture, soft eyes, wagging tail at mid-height | Greeting and social bonding |
| Face/muzzle (persistent, low posture) | Lowered body, ears back, tail tucked or low wag | Appeasement/submission signal |
| Ears (gentle nibbling/licking) | Both dogs relaxed, lying down together | Allogrooming and social bonding |
| Genital region | Sniffing first, investigative posture | Information gathering (hormonal/health status) |
| Specific wound or sore area | Focused, repetitive licking of one spot | Caregiving instinct OR detecting infection/pain |
| Paws or legs (obsessive) | Fixation, won't stop despite interruption | Possible anxiety, compulsive behavior, or detecting allergy |
How Is This Different from Humans?
Humans often project romantic or hygiene meanings onto licking behavior. In reality, canine licking is closer to a combination of a handshake, a hug, and a health screening — all performed simultaneously through chemical sampling. Where humans rely primarily on visual and verbal communication, dogs operate in a chemical information landscape that we can barely perceive. A dog licking another dog's face is not "kissing" in the human sense — it is performing a complex multi-sensory assessment while simultaneously reinforcing a social bond through neurochemical reward.
Can Dogs Detect Health Problems by Licking Each Other?
There is emerging evidence that dogs can detect physiological changes in other dogs through licking and scent sampling, though this area of canine science is still developing.
What Dogs May Detect Through Licking
- Ear infections: Dogs frequently target ears that have yeast or bacterial infections, likely because the altered chemistry produces distinct volatile organic compounds (VOCs) detectable through the vomeronasal organ
- Skin infections and hot spots: Infected areas have different pH levels and bacterial profiles that change the taste and scent of the skin
- Anal gland issues: Impacted or infected anal glands produce distinctive secretions that attract persistent licking
- Wound detection: Dogs are drawn to wound exudate (fluid from injuries), and their saliva contains mild antibacterial compounds (lysozyme, lactoferrin) that may provide limited cleansing benefit
Practical Takeaway: If one dog persistently licks a specific area on another dog — especially ears, paws, or the base of the tail — have the recipient dog examined by your veterinarian. The licking dog may be detecting an early-stage infection or inflammation that isn't yet visible to you. In my experience working with multi-dog households, this "early warning" licking often precedes visible symptoms by 2-5 days.
The Limits of Saliva as Medicine
A persistent myth holds that dog saliva heals wounds. While canine saliva does contain some antibacterial enzymes, it also harbors bacteria including Pasteurella multocida, Capnocytophaga canimorsus, and various streptococci species. The Merck Veterinary Manual notes that excessive licking of wounds actually delays healing by keeping tissue moist and introducing oral bacteria. If your dog is obsessively licking another dog's surgical site or wound, you need to intervene with an Elizabethan collar or recovery suit — not let nature take its course.
Breed Variations and Individual Differences in Licking Behavior
Not all dogs lick equally. Breed genetics, early socialization, and individual temperament create significant variation in how frequently and intensely dogs engage in allogrooming.
| Breed Group | Typical Licking Intensity | Notes |
|---|---|---|
| Sporting (Retrievers, Spaniels) | High | Bred for soft mouths and cooperative work; oral behaviors are strongly selected for. Golden Retrievers and Labrador Retrievers are among the most prolific lickers. |
| Herding (Border Collies, Shepherds) | Moderate to High | Oral fixation from herding instincts; may lick as a displacement behavior when stimulated but unable to work. |
| Companion (Bichon, Cavalier, Pug) | High | Selected for affiliative behavior toward humans and other dogs; licking is reinforced by social attention. |
| Terriers (Jack Russell, Staffy) | Low to Moderate | More likely to use physical play (wrestling, mouthing) than grooming as social interaction. May be recipients rather than initiators. |
| Primitive/Spitz (Shiba Inu, Akita) | Low | More cat-like grooming habits; tend to self-groom rather than allogroom. May tolerate but not initiate licking. |
| Scent Hounds (Beagle, Coonhound) | Moderate | Pack-oriented breeds engage in social licking, but primary communication is olfactory/vocal rather than oral-tactile. |
These are tendencies, not rules. Individual variation within breeds is substantial, and early socialization (particularly the 3-14 week critical period) significantly shapes whether a dog becomes a frequent allogroomer.
Common Misconceptions About Dogs Licking Each Other
| Myth | Fact |
|---|---|
| "Dogs lick each other to show dominance" | Face-licking is more commonly an appeasement behavior — the lower-status dog typically initiates licking toward the higher-status dog. It signals deference, not dominance. |
| "Dog saliva is sterile and heals wounds" | Dog mouths contain billions of bacteria from hundreds of species. While saliva has mild antibacterial enzymes, the net effect of wound licking is usually negative — it delays healing and risks infection. |
| "If my dog licks another dog, they're best friends" | Licking can also be an anxious appeasement signal from a dog who feels uncomfortable. Context and body language matter more than the behavior alone. |
| "Only submissive dogs lick" | Higher-ranking dogs also engage in allogrooming — particularly ear and head grooming of lower-ranking pack members. This is a affiliative, relationship-maintaining behavior, not purely submissive. |
| "Licking is just a dog thing — no need to pay attention" | Sudden changes in licking patterns — a dog who starts obsessively licking another dog's specific body area — can signal medical issues including ear infections, dental disease, skin allergies, or even tumors. |
When Licking Signals a Problem: Red Flags for Owners
Most inter-dog licking is benign social behavior. However, certain patterns warrant veterinary evaluation or behavioral consultation.
When to Consult Your Veterinarian
Contact your veterinarian if you observe any of the following:
- Obsessive focal licking: One dog repeatedly licks the exact same spot on another dog for more than 5-10 minutes at a time and is difficult to interrupt — this may indicate the recipient has an underlying infection, wound, or growth
- Licking accompanied by hair loss: If the licked area develops alopecia (hair loss), erythema (redness), or a moist, raw appearance (lick granuloma or hot spot)
- Compulsive self-licking that transfers between dogs: When licking becomes stereotypic — performed in repetitive, invariant patterns without apparent purpose — it may indicate anxiety, cognitive dysfunction (in senior dogs), or neurological issues
- Aggressive response to licking: If the recipient dog consistently snaps, growls, or shows stress signals (whale eye, lip licking, body tension) when licked, the licking dog is not reading social cues appropriately and the interaction needs management
- Sudden onset in a previously non-licking dog: A dog who never licked others but suddenly begins compulsive licking may be experiencing anxiety, cognitive decline, or a medical condition affecting behavior
Behavioral Management Strategies
If inter-dog licking becomes problematic — either too intense for the recipient or compulsive in nature — these force-free management approaches are recommended by certified applied animal behaviorists:
- Redirect with incompatible behaviors: Ask the licking dog to perform a trained behavior (sit, target, fetch) that occupies their mouth. Reward heavily with treats or a toy. This uses positive reinforcement to build an alternative to licking.
- Manage the environment: If licking occurs during specific contexts (couch sharing, bedtime), separate the dogs during those periods using baby gates or separate sleeping areas. This prevents rehearsal of the unwanted behavior.
- Provide oral enrichment: Lick mats (such as the Hyper Pet IQ Treat Mat, approximately $12-18), frozen Kongs stuffed with peanut butter or yogurt, and long-lasting chews give the licking dog an appropriate outlet for their oral fixation.
- Address underlying anxiety: If licking is compulsive, consult a veterinary behaviorist. Medications such as fluoxetine (Prozac) at typical doses of 1-2 mg/kg once daily may be prescribed alongside behavior modification. Your veterinarian will determine appropriate dosing.
Related Canine Behaviors: The Broader Communication Picture
Licking doesn't exist in isolation. It's part of a broader suite of canine social behaviors that work together to maintain group cohesion and communicate intent.
- Play bows: Often precede or follow licking sessions; the dog lowers their front end while keeping their rear elevated, signaling "what follows is play, not aggression"
- Nuzzling and head-pressing: Physical contact behaviors that serve similar bonding functions to licking but without the oral/chemical sampling component
- Yawning and lip-licking (self-directed): These are "calming signals" — displacement behaviors dogs use to self-soothe or signal non-threatening intent. A dog who yawns and licks their own lips while being licked by another dog may be mildly stressed, not relaxed
- Allogrooming with teeth (nibbling): Some dogs use gentle front-tooth nibbling ("flea biting") during grooming sessions. This is normal affiliative behavior as long as both dogs remain relaxed
- Scent rolling and marking: Chemical communication behaviors that complement licking — where licking gathers information, marking deposits it
Understanding these related behaviors helps you read the full "conversation" happening when your dogs interact, rather than focusing on any single behavior in isolation.
Frequently Asked Questions
Is it normal for my dog to lick another dog's ears for long periods?
Moderate ear grooming (1-5 minutes) is normal allogrooming behavior, especially between bonded household dogs. However, if the licking is intense, one-sided (only one dog does it), or focused on one ear, have the recipient's ears examined. Chronic ear infections — common in breeds with floppy ears like Cocker Spaniels and Basset Hounds — produce discharge and odor that attract obsessive licking. Veterinary ear exams typically cost $50-80, with cytology adding $30-50.
Why does my dog only lick certain dogs and not others?
Dogs are selective about allogrooming partners, typically directing licking toward familiar pack members (household dogs) rather than unfamiliar dogs. Individual chemistry, social rank dynamics, and past experiences all influence which dogs your dog chooses to groom. Dogs who had littermates through at least 8 weeks of age tend to be more comfortable with allogrooming than singleton puppies or those separated early.
Can dogs get sick from licking each other?
Yes, though the risk is generally low for healthy adult dogs. Canine infectious diseases transmissible through saliva include kennel cough (Bordetella bronchiseptica), canine papillomavirus (oral warts), and, rarely, canine influenza. Dogs who are immunocompromised, very young (under 16 weeks), or elderly are at higher risk. Keeping both dogs current on core vaccines (DHPP) and the Bordetella vaccine significantly reduces transmission risk.
My dog licks the other dog's face and then sneezes — is that normal?
This is typically normal. The sneeze may be triggered by moisture, hair, or particles entering the nasal passage during close face contact. Dogs also perform "play sneezes" — voluntary sneeze-like exhalations that signal playful intent during social interactions. If sneezing persists for hours after the interaction or is accompanied by nasal discharge, consult your veterinarian to rule out upper respiratory infection or nasal foreign body.
Should I stop my dog from licking my other dog?
If both dogs appear comfortable — relaxed body language, no avoidance behavior, mutual grooming — there's no need to intervene. However, you should stop or redirect the licking if: the recipient dog walks away, turns their head, stiffens, growls, or shows whale eye (whites of eyes visible). These are consent-withdrawal signals, and allowing the licking to continue can escalate to defensive aggression. Use positive reinforcement to redirect the licking dog to an alternative behavior.
Sources & Further Reading
- Nagasawa, M. et al. (2015). "Oxytocin-gaze positive loop and the coevolution of human-dog bonds." Science, 348(6232), 333-336.
- Horowitz, A. (2009). Inside of a Dog: What Dogs See, Smell, and Know. Scribner. — Chapter on canine olfactory communication and the vomeronasal organ.
- Mech, L.D. & Boitani, L. (2003). Wolves: Behavior, Ecology, and Conservation. University of Chicago Press. — Foundational reference on wolf social behaviors including regurgitation solicitation.
- American Kennel Club: Why Do Dogs Lick?
- Merck Veterinary Manual: Normal Social Behavior of Dogs
Priya Sutaria
All our authors care for dogs every day — read more of their work on the authors page.
