My housemate has a 7-month-old Jack Russel female and I have a 3-month-old Lab female. The two are fantastic friends, almost attached at the hip. Both do well on walks and when greeting other dogs on walks. Occassionaly, however, the Jack Russel just snaps. While playing and sometimes when relaxing, the JR will start snarling and acting more than playful. She gets so boisterous and threatening that I have started to pull the two dogs apart apart. The JR while on the couch with a bone will dive at the Lab who is sometimes more than five feet away minding her own business. Today, the JR lost it and attacked the Lab when I sat down on the couch with a salad. It made me angry that the JR seemed to be imposing her dominance over me and my food. What should I do? How do I handle this situation? Should I seperate them? Should I dicipline either in some way? I usually just seperate the two, but I am not sure if that is the correct approach. Thanks for the help!