My 4 year old Rottweiler, Guiness, growls and bares her teeth when she's happy. The happier she is, the louder she gets. When we pet her, she growls, and if we stop, she nudges our hands. Same when we play with her. She has never bitten anyone, and if my brother, father, and/or I rough house with each other, she snaps at our legs because she thinks one of us is hurting the other and doesn't like it, but will turn her head away if we get too close to her. She doesn't do this with little kids, stays quiet and gentle with them, no matter what they do to her. She barks at people she doesn't know, and that's it. Plays fine with big dogs and tries to protect dogs smaller than her (she has a bad tendancy to lick their muzzles, ears,and eyes- total maternal instincts). I've had conflicting reports from two breeders and a trainer. One breeder never heard of it, the other had, and the trainer said we should hit her with a broom when she did it. Reported him to Animal Cruelty. It doesn't bother us, since we've gotten used to it, and haven't had any problems with her. I would just like to know if it's normal for Rottie's to do this.