How Can You Tell When Dogs Are Playing Nicely?

Doesn’t this photo look scary?  Are these dogs fighting?  Do they need to be separated?  Are they going to hurt each other?

It’s very hard to tell from a photo, but these two dogs are actually playing nicely with each other.  How can we tell?
  • The dogs are not making any loud noises.  Little tiny noises (grunts of effort, small growls) are nothing to worry about.  Loud noises (barking, loud, low growling or constant growling) mean the dogs are starting to get more excited and the interaction should be called off.
  • The dogs’ faces are “soft”.  In the dramatic opening photo, their lips are drawn back, but their cheeks are relaxed and the muscles under their eyes are relaxed.  In other photos in the series, you can see that their lips are relaxed.  (Dogs displaying serious — non-playful — aggression draw the corners of their mouths forward; dogs displaying serious fear draw the corners of their mouths way up and back.)  While they are looking at each other in the header photo, in other photos you can see that they are looking away sometimes, too, and the eye contact is not a hard, maintained stare.  Also, neither dog looks “worried” — eyebrows drawn together, white of eye exposed (“whale eye”), mouth tightly shut, or giving lick intentions.
  • Their ears are back and relaxed.  Ears raised and pointed forward are signs of aggressive arousal; ears pressed flat against the head (almost disappearing into the neck) are a sign of fear.  (Ears drawn back behind the head, hanging down almost like a “ponytail”, are a sign of uncertainty.)
  • Their tails are relaxed, swinging around behind them (the black dog has a relaxed tail — the tailless Corgi is a different story) rather than raised stiffly upright (aggression/arousal) or tucked between the hind legs (fear).
  • Neither dog has “hackles” — raised fur on the back of the neck, the back, and the tail.  Hackles are like human goosebumps — they’re an autonomic reaction the dog cannot consciously control, and they’re a great indicator of how high the dog’s excitement level is.  They don’t necessarily mean aggression, but they do mean the dog is very aroused about something.
  • Biting is inhibited. The dogs are not biting down with their full strength, and are essentially just putting their mouths on each other, not really biting down.
  • The dogs are taking breaks.  Every 20-40 seconds, the dogs will stop engaging with each other, and pause to sniff the ground, scratch, stare off into the distance, just stop and breathe, etc.  This is actually the dogs practicing self-control, and making sure, on their own, that their mock argument doesn’t become a real one.
  • They are evenly matched, and one dog is not playing harder than the other.  Neither dog is firmly “on top”; first one dog chases the other, and then the second dog chases the first.  In an uneven play match, one dog does all the chasing and the other does all the running (and is probably not enjoying the experience).

So that you can see it all in action, here’s a video of the two dogs playing:

Every dog is different, and so play may look a little different depending on the dogs, the time of day, other things present in the environment, etc., but in general the above signs are a good indication that the dogs are just having a great time.
Do your dogs play well together?  What signs tell you your dog is having a good time?