:confused: I have two 10 week old puppies, brother and sister doxies. The past few days the little girl has been showing a lot of aggression towards her brother in their play. They love to rough house, which I know is normal, but just how much aggression is normal. Should I be letting them play at there will, or should I try and stop the real intense aggression. She seem to be biting him unusally hard, and I'm worried.

It is quite normal for puppies to look like they are trying to kill each other. Sometimes is is hard to be sure when to step in and calm things down. As long as no skin is broken, and neither seems to be making serious attempts to get away, and continue to come back for more, it is OK. Often the females are more aggressive.

Before long, they will be starting to lose teeth. If you see blood, before you panic, look at the other one's mouth and see if there is a bloody tooth socket.