I think the title pretty much sums it uo, but here is some back story. I have 2 9/10 year old boxers. One male, one female. Female is fixed. We recently decided to add to the family as we figured the older 2 could teach the young one the ropes. The intro went surprisingly well and everything has been great for a month. As expected the elders snap at her to put her in her place when she's being annoying and we let normaly just watch to make sure it's appropriate. However, Friday morning my adult female jumped on the puppy and I had to physically snatch her off. if she would have stopped once the puppy submitted I wouldn't have been concerned. She gave the pup a small puncher but nothing huge and all seemed fine after. I discussed with my husband and he agreed that it must have been a fluke thing, then Sunday after my nephew had roweled up the puppy it happened again and my husband grabbed her and it just looked like a put in place thing. no markings, no blood. Today she jumped her twice and got her pretty good and for no reason. The puppy is only 14 weeks and my adult female is fixed. We now have them seperate at all times but I don't understand why she is being so aggressive. My 2 older dogs never fight in another. Some growling or a snap but never have I seen them fight in this way. Only once before have I seen my female react aggressively and it was when she was going into heat, 8 or 9 years ago before she was fixed. Anyone have any ideas in what we can do it what may be the cause. The big dogs are not deprived of attention in any way. It anything they get additional attention because we wanted to make sure they didn't feel left out with all the gushy people over the puppy.