My two dogs (Bagel, female welsh corgi mix and Rocket, a shepard mix) have this habit of growling at each other for a long time and wrestling. They show their teeth and bite each other, but not any deep bites or anything (more like nipping). I don't know whether they are play wrestling or are fighting. I do seperate them for a little bit for the day (take one dog out for a walk, then take the other a little later), but it doesn't seem to help too much... which leads me to believe they are just playing. But it does seem a bit rough, so I'm really confused. Any thoughts?