Dogs lick other dogs’ genitals primarily to gather chemical information. What looks awkward or gross to us is actually one of the main ways dogs learn about each other’s age, sex, reproductive status, and overall health. This behavior is rooted in biology and is completely normal in most cases, though occasionally it can signal a medical issue in the dog being licked.
How Dogs “Read” Each Other Through Scent
Dogs have a specialized sensory organ called the vomeronasal organ (or Jacobson’s organ), a cluster of sensory cells located in the roof of the mouth behind the front teeth. This organ detects pheromones, the chemical signals animals produce to communicate biological information. When a dog licks another dog’s genital area, it’s collecting these chemical signals and routing them to the scent-processing areas of the brain.
You may notice a dog smacking its lips or chattering its teeth after sniffing or licking another dog. This movement helps push pheromone-rich molecules toward the vomeronasal organ for processing. The information a dog picks up this way is remarkably detailed: whether the other dog is male or female, spayed or intact, stressed or relaxed, and whether a female is in heat. One specific compound, methyl p-hydroxybenzoate, has been identified in the vaginal secretions of female dogs in estrus. Even tiny amounts of this compound can trigger sexual arousal and mounting behavior in males.
In short, a dog’s genital area is one of the most information-rich parts of its body. Licking it is the canine equivalent of reading someone’s dating profile, medical chart, and mood ring all at once.
It Starts With Mothers and Puppies
This behavior has deep developmental roots. Newborn puppies are entirely helpless. They can’t regulate their own body temperature, move independently, or even urinate and defecate on their own. For the first three to four weeks of life, the mother dog must lick her puppies’ genital and anal areas to stimulate elimination. She also consumes the waste to keep the nest clean and reduce smells that could attract predators.
This maternal licking begins at birth, when the mother cleans amniotic fluid and placental remains from each puppy. It continues as a critical caregiving behavior until the puppies develop enough neurological control to eliminate on their own. Because dogs are wired from their very first moments of life to associate genital licking with care and communication, the behavior carries into adulthood as a normal part of social interaction.
Social Greeting and Status Checking
When two adult dogs meet, genital investigation is standard protocol. A quick sniff or lick communicates who the other dog is and what’s going on with them biologically. This is why dogs at the park often go straight for each other’s rear ends before doing anything else. It’s not rude in dog culture. It’s the handshake.
Some dogs are more persistent about this than others. Intact (unneutered) males tend to be especially interested in sniffing and licking other dogs’ genitals because they’re more attuned to reproductive pheromones. Dogs that are new to each other will typically investigate more thoroughly than dogs who already know one another. And a dog that has recently been to the vet, rolled in something, or is going through a hormonal change may attract extra attention from housemates because it smells “different” and other dogs want to figure out why.
When It Could Signal a Health Problem
If one dog is persistently licking another dog’s genitals well beyond a normal greeting, it may be worth paying attention to the dog being licked. Dogs with infections or inflammation of the genital area produce unusual discharge that can attract prolonged attention from other dogs. Balanoposthitis, an infection of the penis and its surrounding sheath, causes excessive and sometimes pus-like discharge that accumulates around the area. A dog producing this kind of discharge may draw repeated licking from other dogs simply because the smell is strong and unusual.
Watch for these signs in the dog receiving the attention:
- Swelling or redness of the penis, vulva, or surrounding skin
- Unusual discharge from the genitals, especially if it’s yellow or green
- Foul odor that persists between bathroom breaks
- Skin changes like pustules, red bumps, or darkened or rust-colored skin
- Behavioral changes like straining to urinate, going more frequently, or scooting on the ground
There’s also a more serious concern worth knowing about. Canine transmissible venereal tumor (CTVT) is a contagious cancer that spreads through direct contact, most commonly during mating. While it primarily affects the genitals, oral and nasal forms can develop through licking. Free-roaming and intact dogs face the highest risk. Owned dogs that engage in frequent licking of other dogs’ genitals could theoretically pick up non-genital forms of this tumor, though this route is far less common than sexual transmission.
When to Redirect the Behavior
A brief sniff or lick during a greeting is normal and doesn’t need correction. But if a dog is obsessively licking another dog’s genitals to the point where the other dog is trying to move away, snapping, or visibly uncomfortable, it’s reasonable to intervene. Persistent licking can irritate the skin of the dog being licked and create a cycle of moisture and inflammation.
Simple redirection usually works. Call the licking dog away, offer a toy or treat, and reward them for disengaging. If the behavior is constant and seems compulsive, especially if it’s directed at every dog the licker encounters, it may reflect anxiety or an obsessive behavioral pattern rather than normal social communication. In those cases, a veterinary behaviorist can help determine what’s driving it.
If your dog is suddenly getting a lot of genital attention from other dogs when it didn’t before, that shift is worth noting. Other dogs are often the first to detect a change in health status through scent, sometimes before visible symptoms appear. A vet visit to check for urinary infections, hormonal changes, or skin conditions can rule out anything that needs treatment.