Hi, about a month ago my family adopted a half boston terrier half cocker spaniel from the shelter. Today, when I woke him up by petting his head he growled and snapped at me, and stared into my eyes while showing teeth, growling and snarling. This has happened before when I was watching tv and I accidentally dropped my blanket on him. I was really scared but I know I'm not supposed to let him show dominance over me. After, I made him go in the back room we pen him up in at night and lay in his bed. Also, we have had constant issues with marking and we are buying him a belly band to aid that. I am hoping there is a way to discontinue these behaviors, especially what happened this morning. He is also very aggressive with other animals but usually extremely sweet with humans.