Our 7 year old Springer Spaniel has always been a very fisty and spirited girl, but over the last few months, she has become very aggressive. In the past she would not hesitate to snap at us if we were doing something, that was obviously uncomortable...such as cleaning her ears out. In fact both the groomer and vet have a "may bite" warning on her file, thought that was due to our warnings to them. Over the last few months however, she has been extremely aggressive, on more than one occasion to me, my mother, and Dog 2. I can kind of understand her resentment towards the other dog, because she had been an only child until last year, when we found him. Sunday night I was preparing her dinner, and as I was setting it down on the floor, she grabbed my wrist in her mouth hard enough to draw a signifcant amount of blood......Hubby wanted to take me to the ER but it was fine. I took her to the vet today to rule out any infections or injuries that might cause pain and irritability and she checked out fine. I am wondering if anyone else has ever a sudden increase in aggresive behavior with their dogs and what they did about it.