My dog ​​attacked out of the blue

A dog that doesn't "warn" is a dog that no longer expresses any body language and/or vocal expression before attacking.

A dog's seemingly calm behavior sometimes actually veils a high emotional state. Not confusing your dog when he's inactive, when he's calm, and when he's inhibited will help you avoid or understand some hostile behaviors.

Let's start with some definitions (from Larousse.fr)

• Inactive

An inactive dog is a dog that is not doing an activity.

For example: your dog watches you (= he exhibits a behavior) working on your computer, while lying down (= he isn't doing any activity).

• Calm

A calm dog doesn't get agitated or fidgeting. 

For example: you are walking your dog and he sniffs the scents (= he is engaged in an activity) with a regular rhythm, smooth movements, a tail that wags slightly to the right (= he is showing positive emotion without showing agitation).

• Inhibited

An inhibited dog is in a state of inhibition, meaning he does not exhibit, or exhibits less of, a behavior that, in another similar situation, would have been present or showed at a higher arousal state.

For example: your dog cannot stand strangers touching him and usually barks at them, but is silent at the vet, his limbs tensed, his ears back.

A dog that is inhibited opts for a particular strategy in a situation that makes him uncomfortable, or even frightens him. He is then highly likely to release what he has accumulated during this experience. To do this, depending on his personality, his learning, and the parameters of his immediate environment, he may: hump, shake off, bite, bark intermittently, or pull on the leash.

An inhibited dog is one that hold it back when the same situation, in a different environment, would otherwise cause him to show hostile or avoidant behaviors.

By recognizing when your dog is showing inhibition, you can provide support, help him relax, offer him a decompression chamber, and teach him to redirect his negative emotions without risk to other individuals.