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Your dog yawns halfway through a visitor's enthusiastic hello. A moment later, the tongue flicks over the nose. Perhaps you have been told this means “calm down”, or that a yawn copied from you proves a special bond. It is a lot of meaning to place on a brief movement.
Dogs Trust advises checking the situation and the whole dog. Lip licking around dinner can reflect food anticipation; the same movement elsewhere can accompany worry1.
What the word calming asks us to establish
The term “calming signals”, popularised by trainer Turid Rugaas, proposes that certain behaviours reduce conflict. A pilot study followed 24 focal dogs through four short meetings each with familiar and unfamiliar dogs2.
Researchers grouped many behaviours, including nose licking, head turning, freezing and yawning. They recorded 109 aggressive episodes. After 73 of these, the focal dog showed at least one grouped signal; in 58 of those 73 cases, the other dog's aggressive display subsequently decreased2.
That is suggestive evidence for a social role. It does not isolate a yawn's effect, prove that the movement caused the change, or establish that every behaviour in the group works identically. The study excluded dogs with problems that could compromise the meetings, limiting generalisation to other encounters2.
The distinction is useful: observing a movement and showing that it calms a recipient are separate claims. The latter needs evidence about the recipient's response2.
What approaching humans revealed
A later experiment exposed 53 dogs to unfamiliar people approaching in either a mildly threatening or neutral manner. Researchers examined specific behaviours separately. Blinking, nose licking and lip wiping occurred more in dogs classified as non-reactive, across both types of approach3.
Most of these behaviours did not become more frequent specifically in the threatening condition. Head turning showed a more complicated relationship with the situation and the dog's reaction. The authors concluded that a calming function remained unconfirmed, even though some behaviours were associated with a less aggressive response3.
Yawning was too uncommon in this experiment for meaningful statistical analysis. That detail matters: findings about nose licking or blinking cannot automatically be relabelled as findings about yawns. A category that feels convenient in everyday conversation can contain behaviours that need separate investigation3.
The people also followed prescribed approaches. This design examined how dogs responded to people behaving in particular ways; it did not demonstrate that a dog's lip lick persuaded a person to abandon an angry approach3.
Lip licking needs more context
Research published in 2026 adds another complication. In an analysis of 64 dogs, researchers coded behaviour during a structured series of separations from, and reunions with, owners and a stranger. They also collected physiological measurements, including salivary cortisol and oxytocin4.
Lip licking varied between episodes, but did not follow a simple pattern of increasing whenever expected stress increased. Its relationships with hormone changes differed between attachment groups. These were exploratory correlations, involving small groups and without correction for multiple comparisons4.
That gives a reason to resist reading each tongue flick as one extra unit of stress. It also leaves the mechanisms open: a correlation between a behaviour and a hormone cannot establish which causes which. Yawning was again too rare for the study's inferential analyses4.
The researchers used a particular laboratory procedure and behavioural classifications. Their results do not give owners a way to diagnose an attachment style from a dog licking its lips at home4.
Catching your yawn is no test of affection
One earlier study of 25 dogs found more yawning after a person yawned than after control mouth movements. Yawn frequency was greater with the owner than a stranger. Usable heart-rate recordings from 21 dogs showed no significant differences between conditions5.
The authors favoured an empathy-related explanation over stress alone. However, the physiological finding is a result from this experiment, rather than a guarantee that every dog copying a yawn is unstressed. The study included dogs comfortable around strangers and used a controlled procedure in familiar rooms5.
A larger reanalysis subsequently combined data from six studies, covering 257 dogs. It supported contagious yawning, but found no evidence that familiarity with the person, or the dog's sex, explained the response as predicted by the empathy hypothesis6.
The same researchers tested 32 dogs after positive interactions with one person and less friendly interactions with another. Dogs did not yawn more for the person who had behaved positively. The results challenge yawning as an indicator of empathy, while leaving dogs' wider emotional capacities open6.
You do not need to stage a yawning contest to check your relationship. Whether your dog copies one particular movement is a very narrow event to ask to carry that much emotional weight.
Fireworks show why a checklist can mislead
A video study compared 36 dogs during real fireworks with the same dogs on quieter evenings. Owners had reported some welfare impact from fireworks; dogs with none reported were excluded. The researchers coded recordings rather than exposing dogs to an extra noise test7.
During fireworks, the dogs' ears were directed further backwards, and they spent more time moving and panting. Yet yawning and lip-licking rates did not differ significantly between the two conditions. Several other apparent differences also failed to remain significant after accounting for multiple comparisons7.
The result does not make lip licking irrelevant to every stressful situation. It shows that a behaviour can fail to rise during a particular fear-provoking event. Equally, missing yawns in a fireworks video cannot establish that a dog is coping comfortably7.
There were individual differences, and owners continued their usual ways of supporting their dogs. The comparison gives a useful warning about treating one short list of movements as a universal fear detector7.
Give your dog some room to answer
Dogs Trust recommends stopping an interaction and identifying the cause when a dog shows anxiety. Move away from what worries them and ask others to give space. This is a practical response to the whole picture, without needing a final verdict about a signal's function1.
A more useful observation
For example, you might tell a visitor, “Let's pause the greeting.” That gives you a chance to reconsider what is happening, without announcing that you have decoded your dog's private thoughts. Your account can stay modest: what you saw, the circumstances, and what happened after the pause.
Check physical comfort as well
PDSA notes that dogs may drool and lick their lips when they feel sick. Excessive drooling can also accompany dental problems or something stuck in the mouth, among other causes. A change in drooling deserves veterinary advice, rather than an assumption that it is social communication8.
A vet will consider the history, examine your dog and decide whether further investigation is needed. Behavioural and physical explanations need an appropriate assessment; a video of a tongue flick cannot choose the treatment8.
For the visitor's next hello, a pause gives you room to reconsider the whole picture1.
Sources and further reading8 sources
The small numbers in the article link to the source behind each fact. Sources open on their own websites.
- How to understand your dog's body language
- Analysis of the intraspecific visual communication in the domestic dog (Canis familiaris): A pilot study on the case of calming signals
- Appeasement function of displacement behaviours? Dogs’ behavioural displays exhibited towards threatening and neutral humans
- Rethinking dog stress behaviours: contextual and physiological insights from the attachment framework
- Familiarity Bias and Physiological Responses in Contagious Yawning by Dogs Support Link to Empathy
- Contagious yawning is not a signal of empathy: no evidence of familiarity, gender or prosociality biases in dogs
- Fear expressions of dogs during New Year fireworks: a video analysis
- Drooling in dogs