Aggression in dogs is often seen as a purely behavioral problem. A dog that lunges, growls, or bites is quickly labeled "dominant," "untrustworthy," or a "problem dog." Yet, experience shows time and again that aggression rarely occurs in isolation. In many cases, it's a manifestation of underlying physical complaints, pain, or internal imbalances .

When a dog consistently feels unwell, experiencing constant discomfort or pain, its nervous system becomes strained. Its tolerance to stimuli decreases, stress builds, and the dog quickly pushes itself beyond its limits. Behavior is then not a cause, but a signal .

The story of Tjekko is a striking example of this.