Dogs can growl, chase and wrestle during play, but a single sound or posture does not reliably tell you whether an interaction is safe. Watch both dogs, the setting and changes over time.
Look for choice and comfort
Loose movement, pauses and voluntary re-engagement can be useful observations. Repeated attempts to escape, freezing, marked tension, persistent pursuit or escalation are reasons to interrupt safely and create distance. Raised hackles can reflect arousal and are not by themselves a diagnosis of aggression.
Give dogs space and an easy way to disengage. Keep unfamiliar dogs apart until an appropriate introduction can be arranged. A busy parking lot or off-duty service dog is not an invitation to stage a test.
When to stop
If either dog appears distressed, stop the interaction. Do not continue handling or play out of concern that stopping will reward fear. Do not punish a growl or force dogs to work it out.
Supervise children and dogs actively. Separate them when supervision is unavailable. Avoid reaching between fighting dogs; seek an individual prevention and emergency plan from a qualified professional.
Get help early
Resource guarding, repeated conflict, bites or a sudden behavior change warrants veterinary and qualified behavior support. Pain or illness may contribute, and a written article cannot diagnose the cause. Use humane, reward-based methods and manage access to risky situations while getting help.
This revision retains the original article’s topic and contributor attribution to Karen Backhouse/Tromplo while updating its behavior guidance.