Corners of the Mouth in Dogs: Reading body language correctly
Corners of the mouth in dogs: reading body language correctly
What is the corner of the mouth in dogs?
The corner of the mouth (commissura labiorum) is the point where the dog’s upper and lower lips meet. As part of the facial musculature of the dog’s face, the corner of the mouth changes its position depending on the animal’s emotional state — directed forward, neutral, or pulled back and downward.
The position of the corners of the mouth is a reliable signal within the overall picture of canine communication. Viewed in isolation, it is difficult to interpret — in the context of other body language signals (ears, eyes, posture, tail position), it provides valuable indications of tension, relaxation, or appeasement.
Background + scientific classification
Rugaas (2006, On Talking Terms with Dogs: Calming Signals) describes changes in the corners of the mouth as part of the calming repertoire: corners of the mouth pulled back and downward — often accompanied by a lowered head, lowered gaze, and ears held back — signal appeasement or submission toward another individual. This signal appears in stressful situations or when a threat is perceived. Rugaas distinguishes between genuine calming signals (directed at another individual) and general stress signs — retraction of the corners of the mouth can represent both. Contextualization is essential: a dog that is jumping happily while showing the corners of the mouth is communicating differently from a dog frozen rigidly with identical facial expression.
Beaver (2009, Canine Behavior: Insights and Answers) systematically describes how canine facial expressions work: the submissive grin is a specific configuration of the corners of the mouth — corners of the mouth pulled back with the mouth slightly open, often accompanied by blinking. It is not a threat of aggression, but a pronounced calming signal. Beaver explains that owners often mistakenly interpret this grin as growling or a threat to bite — which leads to inappropriate responses. Neutral corners of the mouth with a relaxed, half-open mouth (light panting) signal relaxation.
Waller et al. (2013, PLOS ONE, https://pubmed.ncbi.nlm.nih.gov/24358183/) examined paedomorphic facial expressions in domestic dogs compared with wolves: compared with wolves, dogs have a more pronounced levator anguli oculi medialis (LAOM) — a muscle that raises the inner eyebrow and creates the “puppy-dog eyes” expression. In dogs, this muscle has become strongly developed through the domestication process. The authors suggest that facial expressions (including combined mouth-corner and eye configurations) have evolutionarily supported the human-dog bond. In dogs, facial musculature is therefore not incidental, but selectively shaped.
Vitomalia position
Mouth corners are a single signal within a complex communication system. In isolation, they should not be overinterpreted — the overall context is decisive. A pulled-back mouth corner in a stressful situation is a warning sign that should be taken seriously. The submissive grin is often misread — if it is misunderstood as a threat, the response to a dog seeking de-escalation will be inappropriate.
When do the corners of the mouth become relevant?
- Stressful situations: pulled-back mouth corners as one of several signs of stress
- Encounters with people or dogs: recognize calming signals early
- Submissive grin: interpret correctly as appeasement, not as aggression
- Pain: tense mouth muscles as an indicator of pain
- Behavior training: essential knowledge for recognizing emotional states
Practical application
Mouth corner positions at a glance:
| Position | Appearance | Possible meaning |
|---|---|---|
| Neutral/relaxed | Mouth slightly open, corners relaxed | Relaxation, curiosity |
| Back and downward | Mouth corners pulled back, mouth closed/slightly open | Stress, appeasement, submission |
| Submissive grin | Pulled far back, mouth open, teeth visible | High-level appeasement (not an attack) |
| Tense, forward | Lips tight, mouth corners forward | Warning, threat (part of aggressive facial expression) |
Important accompanying signs: - Mouth corners + ears pinned back + lowered tail: clear signs of stress - Mouth corners + narrowed eyes + body tension: discomfort - Mouth corners + loosely hanging tail + relaxed body: relaxed communication - Mouth corners alone: always assess them in the overall context
Common mistakes & myths
- “Showing teeth is always a threat.” The submissive grin shows teeth — but it is the opposite of a threat. Key features: mouth pulled far back, relaxed body posture, no growling, avoidance of eye contact or soft eyes.
- “The corners of the mouth can be read clearly.” A dog’s facial expression is always context-dependent. The same mouth corner position can indicate appeasement, stress, or joy in play — depending on the overall situation.
- “My dog is grinning because he is angry.” Many dogs show the submissive grin as a greeting ritual toward close attachment figures. It is a positive bonding signal and not a sign of aggression.
Scientific status 2026
Research into facial communication in dogs has developed considerably since the 2000s. The work by Waller et al. (2013) on muscle development through domestication makes clear: canine facial expressions are not random, but evolutionarily shaped. Current research examines the coding of facial expressions (Facial Action Coding System adapted for dogs — DogFACS) and how people perceive these signals. Training in body language — for dog owners, trainers, and veterinarians — is a growing field of application.
Frequently asked questions
What does it mean when a dog pulls back the corners of its mouth?
Retracted corners of the mouth often indicate stress, appeasement, or submission. The full picture emerges from the overall context (body posture, ears, tail). This signal should not be overinterpreted in isolation.
What is the submissive grin in dogs?
The submissive grin is a strongly retracted corner-of-the-mouth position in which the teeth become visible — but without growling and with a relaxed body posture. It is a very clear calming signal and not a sign of aggression.
Can I tell from the corners of the mouth whether my dog is in pain?
Pain often causes tension in the mouth muscles — stiff-looking lips, a tense jaw. In context with other signs of pain (protective posture, changed behavior), the face can be an indicator, but not a sole diagnostic criterion.
Related terms
- body language in dogs
- calming signals in dogs
- stress signals in dogs
- Facial expressions in dogs
- Communication in dogs
Sources & further reading
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Rugaas, T. (2006). On Talking Terms with Dogs: calming signals (2nd ed.). Dogwise Publishing. ISBN 9781929242368.
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Beaver, B. V. (2009). Canine Behavior: Insights and Answers (2nd ed.). Saunders. ISBN 9781416066477.
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Waller, B. M., Peirce, K., Caeiro, C. C., Scheider, L., Burrows, A. M., McCune, S., & Kaminski, J. (2013). Paedomorphic facial expressions give dogs a selective advantage. PLOS ONE, 8(12), e82686. https://pubmed.ncbi.nlm.nih.gov/24358183/