My 2 1/2 year old female White German Shepherd attacked my female Cocker Spaniel last night. She was given to me a year ago by some people that bought her from a breeder as a gift. She ended up unwanted, so I took her. This is the second time it has happened. She collects things like wood and other objects and guards them. She had a log laying on the lawn that she had found. My Cocker Spaniel was laying on the grass near the log. Without warning, she growled ferociously and pinned her with her teeth! I sprayed her with water to get her off Scarlett. The other time she attacked her, it was over a pillow that she had stolen from inside the house and put on the lawn. I got the pillow and was taking it back in the house. Scarlett was sitting on the patio. When I walked past Scarlett with the pillow, Sabra (the WGS) turned and attacked Scarlett. She didn't want the pillow near Scarlett. She also growled and pinned a little female Chiweenie about a week ago. The Chiweenie is displaced by the tornado and staying with me right now. Sabra loves my male Cocker Spaniel. She also gets along great with the 2 male Chiweenies staying with me. I think she has an issue with females. I had someone that works for a rescue tell me that it is common that female GS dogs do not like other female dogs. I was hoping there is someone knowledgable about dogs that could give me some advice? Have any of you ever had this happen? I don't know what to do. I don't want her to hurt other dogs.