07/01/2026
Any time you see a shift in behavior, it's worth a call to your vet to determine if there is an underlying medical condition. A large percentage of "aggression" is related to undiagnosed pain.
One of the most common things dog professionals hear is, âThere are no signs of pain.â
Yet the dogâs behaviour has changed, escalated, or become unsafe.
Here is the key point. Behaviour is how dogs communicate discomfort. Dogs do not use words. They use actions. If behaviour changes, that change is a sign.
Dogs are biologically wired to hide pain. In the wild, showing weakness reduces survival. Research shows dogs often compensate for discomfort by shifting weight, altering posture, avoiding movement, or becoming more sensitive long before obvious limping appears. By the time pain looks âclear,â it is often advanced.
Pain and behaviour are not separate. Pain alters the nervous system, lowering tolerance and increasing irritability and fear. Studies consistently link pain with aggression, reactivity, anxiety, night-time restlessness, avoidance of handling, and sudden snapping (Mills et al, 2020). Treating pain often reduces these behaviours, not because the dog is ânicer,â but because the dog is more comfortable.
A dog can still run, play, and appear happy while in pain. Adrenaline and excitement mask discomfort. Many painful dogs show subtle signs instead, such as pulling on the lead to offload weight, reluctance to sit or lie down, stiffness after activity, sensitivity to touch, lip licking, or increased reactivity in the evenings.
âMildâ findings on scans do not mean mild pain. Research shows pain severity does not always match imaging results. Behaviour reflects the dogâs lived experience, not the appearance of an X-ray.
When pain persists, behaviour often worsens. Chronic discomfort sensitises the nervous system, making dogs defensive and reactive. Training alone cannot fix pain. Addressing discomfort alongside behaviour support leads to better learning, regulation, and welfare.
Behaviour is not separate from pain.
Behaviour is often the symptom.