Why Dogs Lick Other Dogs or People on the Mouth

Dogs lick other dogs or people on the mouth for various instinctive reasons, mainly for social bonding, communication, and grooming. While this behaviour can seem endearing, understanding why your dog does it helps you interpret their feelings and intentions better, ensuring a happy and healthy relationship between you and your pet.

However, while licking is natural in the canine world, it doesn't mean it's always desirable or acceptable behaviour, particularly when directed at humans or unfamiliar dogs.

Licking as a form of communication

Dogs primarily lick each other's mouths as a way of communicating. Licking around the muzzle of another dog is often a gesture of submission or appeasement, signalling that the dog means no harm and respects the other dog's authority.

Within a dog pack, lower-ranking dogs would lick the mouths of higher-ranking ones as a sign of respect and submission. This behaviour can also appear in domestic dogs when they encounter a dog perceived as more dominant.

Social bonding and grooming

Licking in dogs serves an important social bonding function. When dogs lick each other, particularly around the mouth and face, it's often a way of maintaining social bonds, showing affection, and establishing trust.

This behaviour originates from when they were puppies, as mother dogs lick their puppies to groom them and stimulate them. As dogs grow, licking remains an important social activity that facilitates bonding among pack members.

Seeking attention or food

Sometimes, dogs lick people or other dogs around the mouth simply because they're seeking attention or food. In the wild, young wolves lick the mouths of adult pack members to encourage them to regurgitate partially-digested food.

While your dog might not actually expect you to regurgitate food, the instinct to lick can remain as a means of seeking food or attention. If your dog gets a positive response (like laughter, petting, or food) when they lick your mouth, they're likely to repeat this behaviour.

Investigating scent

Dogs gather a lot of information from scent. When a dog licks another dog or human's mouth, they might be trying to discover what that individual has recently eaten or detect scent markers left by pheromones in saliva.

This investigative behaviour is part of how dogs understand their world and the individuals within it. By licking, a dog can gain insights into the health, diet, and emotional state of the individual they're licking.

Is it safe for dogs to lick people's mouths?

While the gesture itself is usually harmless, there are some health considerations to keep in mind. Dogs can carry bacteria in their mouths, some of which could potentially be harmful to humans, particularly those with compromised immune systems.

There's also the consideration that dogs often lick less-than-hygienic things, including their own bodies. As such, while occasional kisses from your dog are usually fine, it may be best to discourage excessive licking around the mouth, particularly for young children or people with weakened immune systems.