Dog Interdog Aggression: Assessment and Safe Management

Aggression between dogs — whether in the same household or in public — is a complex welfare and safety concern requiring careful assessment.

Key Facts

Interdog aggression is the second most common aggression type presented in behaviour consultations
It often has multiple motivations including fear, resource competition, redirected frustration, and play escalation
Dogs living together can develop inter-household aggression that may emerge suddenly after months of peaceful coexistence
Triggers including food, toys, owner attention, and tight spaces commonly precipitate aggression between dogs
Management includes resource separation, structured interactions, and behaviour modification
Permanent separation may be the most welfare-positive outcome for truly incompatible household dogs

Welfare Considerations

Interdog aggression in shared households causes chronic stress for all dogs involved — not just those directly fighting. Dogs that must constantly navigate tension or avoid triggers cannot rest, eat, or interact normally. Welfare assessment must consider every dog in the household, not just the apparent aggressor. Behaviour modification can reduce reactivity but cannot guarantee safety in incompatible pairs. Welfare-centred management may conclude that permanent separation — either within the household or through rehoming — is kinder than forcing coexistence that maintains chronic stress and ongoing injury risk for both animals.

What You Can Do

Seek a qualified behaviourist assessment early — interdog aggression rarely resolves without professional guidance
Manage the environment to prevent access to known triggers during the assessment and modification period
Consider permanent separation of dogs that cannot be safely managed together despite intervention
Never punish dogs for aggression — it increases fear and worsens the underlying problem
Ensure all dogs in a multi-dog household have individual space where they cannot be approached by others