I have a one-year-old female golden/lab mix (Scout) and a 10-month-old female chocolate lab. We have done well together up until just recently when they had a change in environment for a few weeks. They have always wrestled and played rough, using their mouths a lot. But during this time, Scout bit Java's ear so that she needed stitches. Then a week later, I found the bandage off with another wound to her ear. I witnessed the first "scuffle" and could tell exactly when it went from "play" to "fight". This has happened only a few times during the past year. Now it seems like they are on the verge of this aggression toward each other more often. They do NOT listen to me when I verbally attempt to separate them. I am very worried they may hurt each other again. I don't know if this is normal at this time in their development (both being around 1 year old females) perhaps trying to establish their dominance. Just supervising their time together doesn't help because the incidents happened in a split second. I love them both dearly. Please let me know how concerned I should be....thank you